OF REVIEW CURRENT ESTIMATING CAPABILITIES OF THE 3D BUILDING INFORMATION MODEL SOFTWARE TO SUPPORT DESIGN FOR PRODUCTION/CONSTRUCTION
By Toni Farah A thesis submitted to the faculty of the Worcester Polytechnic Institute in partial fulfillment of the requirements for the degree of
Master of Science
July 2005
Approved by: ________________________________________________________ Professor Guillermo F. Salazar, Thesis Advisor
________________________________________________________ Professor Roberto Pietroforte, Thesis Committee Member
________________________________________________________ Professor Frederick Hart, Department Head
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ABSTRACT
The fragmented environment in the construction industry has a big influence on production. The multi-disciplinary nature of the project development process imposes the need for clear communications and team effort coordination. Information Technology (IT) has been playing a tremendous role in facilitating this process. The most recent contribution of IT in this regard is the Building Information Model (BIM). It is clear that BIM technology improves the design drawings productivity; drawings are automatically coordinated in all views from plans, to sections, to elevations, to details and to perspectives. It also provides an innovative way of scheduling through by allowing a 3D visualization of the construction progress. But, there are still many technical issues that still need to be addressed before this technology is fully adopted by the industry. For example, what are the files formats that BIM supports? What is the needed knowledge for best use of BIM? How does BIM integrate with the estimating discipline? Where does BIM store the building data? What are the codes that are shown in the automatically generated quantity take-offs schedules? This research attempts to provide answers to these questions and explores possible ways to link different coding systems within the BIM platform itself. After reviewing the basic design concepts from the conceptual to the construction stages and how it is related to the different project delivery ways, this work illustrates the role of different work breakdown structures (WBS) in the life cycle of estimating discipline from the preliminary to the detailed stage. The research reviewed the different database designs and structures, the database management systems (DBMS), as well as the database organization systems. This review draws a picture on how information
system (IS) and its tools support the different needs of the multiple players involved in a construction project. The focus was on the object oriented database and building information model (BIM) software, and how it integrates with other estimating and project planning software. The findings seem promising, but before BIM technology can reshape the construction industry, it is still necessary to conduct additional experimental work as the software continues to evolve and becomes mature.
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ACKNOWLEDGMENTS
The author wishes to thank God, his mentor and all family, friends and colleagues whose continuous supports have made his goal come true.
This research would not have been possible save for the encouragement, guidance and brilliance of Professor Guillermo F. Salazar and for the support of Mr. Ken Stowe (AutoDesk Revit). It would not have been written had Professor Roberto
Pietroforte not awakened the authors interest in a better contribution from the architect side in the construction management practice, and had Mr. Frederick Mulligan and Mr. David Dutton (Cutler Associates) not tremendously enriched his knowledge in the estimating discipline.
Every attempt has been made to give credit to quoted sources. While many contributed in ways large and small to the development of this report, the errors in content are the authors responsibility. In spite of everyones best efforts, he is sure that he has left many opportunities for improvements.
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Finally, the author would like to dedicate this work to his parents, whom love, devotion and prayers have been inspiring him for a continuous strive in life and for intellectual achievements.
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TABLE OF CONTENTS
Abstract ........................................................................................................................... 1 Acknowledgments........................................................................................................... 3 Table of Contents............................................................................................................ 5 List of figures.................................................................................................................. 7 Chapter 1. Introduction.................................................................. 8 1.1 Big Picture ...................................................................................................... 9 1.2 Building Information Model (BIM) Tools.................................................... 11 1.3 Specific Objectives and Scope...................................................................... 12 1.4 Methodology ................................................................................................. 12 1.5 Results........................................................................................................... 13 Chapter 2. Architectural design process ......................................14 2.1 Construction Delivery Systems..................................................................... 14 2.2 Design Stages, BIM Technology and Cost Estimate .................................... 16 Chapter 3. Overview of the cost estimating process ....................19 3.1 Estimating Techniques.................................................................................. 19 3.2 Role of Software to Support Cost Estimates Generated by the Architect .... 22 3.3 BIM, Estimating Categories and Project Management................................. 24 3.3.1 Order of magnitude (O/M) estimate ......................................................... 24 3.3.2 Conceptual estimates or systems estimates............................................... 25 3.3.3 Detailed estimate....................................................................................... 26 3.3.4 Appraisals ................................................................................................. 27 Chapter 4. Database types and management ...............................28 4.1 Database Designs .......................................................................................... 29 4.2 Database Management System (DBMS) ...................................................... 30 4.3 Object Oriented DBMS and Architectural Practice...................................... 31 4.4 Current Estimating Practice .......................................................................... 32 4.4.1 Spreadsheets vs. Commercial Software Packages .................................... 33 4.5 BIM and Database Management & Costs Updates....................................... 34 4.6 BIMs Interface with Estimating Software ................................................... 35 4.7 BIMs Interface with Scheduling Software .................................................. 35 Chapter 5. Database Organization, Formats .................................37 5.1 Database Organization and Coding Systems ................................................ 38 5.1.1 Database and Construction Systems ......................................................... 38 5.1.2 Database Formats and Published Cost Data ............................................. 41 5.2 Quick comparison between database formats............................................... 42 5.2.1 CSI Master Format and RS Means Building Construction Cost Data... 44 5.2.2 Uniformat 1 & 2 and RS Means Square Foot Cost Data .......................... 45 5.2.3 Uniformat 2 and RS Means Assemblies Cost Data .................................. 46 Chapter 6. Overview of some available tools................................48 6.1 Information Systems (IS).............................................................................. 49 5
6.1.1 Management System in the Construction Industry................................... 50 6.1.2 Information System in the Construction Industry..................................... 51 6.1.3 Project Control System in the Construction Industry ............................... 52 6.2 Some available tools ..................................................................................... 52 6.2.1 Timberline Office Estimating (http://timberline.com/software/default.aspx)........................................................... 54 6.2.2 AutoDesk Revit (http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=331041) ............. 60 6.2.3 Graphisoft ArchiCAD (http://www.graphisoft.com//products/archicad/) 65 Chapter 7. Case Study ..................................................................72 7.1 Methodology ................................................................................................. 72 7.1.1 First Scenario: AutoDesk Revit ................................................................ 74 7.1.2 Second Scenario: Graphisoft ArchiCAD .................................................. 80 Chapter 8. Results (Accomplishments, ........................................86 8.1 Accomplishments.......................................................................................... 86 8.1.1 First Scenario: AutoDesk Revit 6.0 and estimating.................................. 86 8.1.2 Second Scenario: Graphisoft ArchiCAD 8.1 and estimating.................... 87 8.2 Testing and Limitations ................................................................................ 89 8.2.1 First Scenario: AutoDesk Revit 6.0 .......................................................... 89 8.2.2 Second Scenario: Graphisoft ArchiCAD 8.1 ............................................ 91 8.3 Conclusion .................................................................................................... 92 Chapter 9. Recommendations ......................................................93 9.1 Recommendations......................................................................................... 94 Appendix A Master Format (CSI-16 divisions) .............................96 Appendix B Master Format (CSI-50 divisions) ........................... 100 Appendix C Uniformat 1 (12 divisions) ...................................... 101 Appendix D Uniformat 2 (8 divisions) ........................................ 109 Appendix E Sample page- BCCD (RSMeans) ............................ 111 Appendix F Sample pages- SFC (RSMeans) ............................. 112 Appendix G Sample pages- SF&AEM (RSMeans) ...................... 114 Appendix H Sample pages- Uniformat 2 links ........................... 115 Appendix I AutoDesk Revit 6 Features and Benefits.................... 116 Bibliography ............................................................................................................... 128
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LIST OF FIGURES
Number
Page
Figure1. Triangular relationship ......................................................................................... 8 Figure2. Traditional Contractual approaches.................................................................... 15 Figure3. Turnkey contractual approaches......................................................................... 16 Figure4. Alternate contractual approaches ....................................................................... 16 Figure5. Role of estimates in the Project Management Environment .............................. 20 Figure6. Library-Database in Revit (upper) and in ArchiCAD (lower) ........................... 24 Figure7. AutoDesk Revit feature of generating O/M estimate ......................................... 25 Figure8. The Database ...................................................................................................... 28 Figure9. Contractors Database Life Cycle ...................................................................... 32 Figure10. Code-Glue used by different management systems ......................................... 39 Figure11. Project cost code structure based on functional organization .......................... 41 Figure12. Level 1 numbering systems of Databases components................................... 44 Figure13. Levels 1 to 5 numbering systems for unit price line item ................................ 45 Figure14. Levels 1 to 5 numbering systems for assembly price line item........................ 47 Figure15. Relationship Between Systems ........................................................................ 49 Figure16. Project Control System..................................................................................... 52 Figure17. Timberline - CAD integrator with IFC file ...................................................... 55 Figure18. Timberline Uniformat I/Master Format phasing feature ............................... 56 Figure19. Timberline/TRA-SER Pro interface ................................................................. 57 Figure20. Timberline/Sure Track interface....................................................................... 58 Figure21. Revit Design Bar and Project Browser.......................................................... 63 Figure22. ArchiCAD Design and Animation Tools ...................................................... 67 Figure23. ArchiCAD Central Objects Database............................................................ 69 Figure24. ArchiCAD GDL Object Library.................................................................... 69 Figure25. ArchiCAD Databases in Active Libraries ..................................................... 70 Figure26. ArchiCAD Link Central Objects to Active Database By Criteria................. 71 Figure27. Revit Settings Pull Down List ....................................................................... 74 Figure28. Revit Element Properties............................................................................... 76 Figure29. Revit Project Parameters ............................................................................... 76 Figure30. Revit Template Report exported into MS Excel ........................................... 77 Figure31. Revit - Multi category Schedule into MS Excel............................................... 78 Figure32. Primavera Planner generated work schedule.................................................... 79 Figure33. ArchiCad Layers Settings and Combinations................................................ 81 Figure34. ArchiCad Objects parameters and layers ..................................................... 82 Figure35. ArchiCad Federated databases in active libraries.......................................... 82 Figure36. ArchiCad Full Door Schedule (upper) and Basic Element Schedule (lower)84 Figure37. ArchiCad Project Publisher ........................................................................... 84
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Chapter 1.
Introduction
In popular terms it has been commonly known for long time that Time is Money. In the industrial world and construction industry in particular, Time, Money and Quality form a triangular relationship (See Figure1). In the majority of decision making occasions, management has to compromise in one area in order to get the best result in the other two. Mainly, Money and Quality are always fighting for Time.
TIME
MONEY
QUALITY
Figure1. Triangular relationship
Id like to see the architect become the master builder again - said well known and controversial architect Frank O. Gehry (ENR 02/28/00 p. 76-83). He had directed CAD-enabled construction and had relied on computer integrated technology to transform Frank O. Gehry & Associates (FOGA) design of Experience Music Project into a reality. Architect Frank Gehry knew that the construction industry is very fragmented, and in order to successfully build an exceptional geometry, he had to build a construction team that is appropriate for his project. He had to provide the steel fabricator, the general 8
contractor and the structural engineer with electronic design that could be used by their systems and could be implemented in their firms, in order to execute the project on time. CATIA software was used by FOGA to generate the drawings, other corresponding robotics software were used in the manufacturing process of the structural shell, and Pro Engineer structural software was totally integrated with CATIA and had automatically both calculated and described the metallic sheets and frames of the buildings exterior shell.
1.1
Big Picture
In the present time, the Architect/Master Builder concept has been rarely
employed in the construction industry. The construction project has a life cycle that starts when an owner identifies an opportunity and that ends when an organization operates and maintains the building. In commercial buildings, productivity and timely construction rely on the team members: owner-architect-engineer-contractor-builder and on their inter-relationships. Since every player has different interest in the project, the concept of partnership among all involved parties becomes critical, in order to improve the production of a building (from a time and cost point of view).Their reliance on computer software to improve the efficiency of planning, building and managing a project have been tremendously growing in the last few years.
Its in the earliest stages of a project, particularly during the programming, schematic and preliminary stages that crucial design decisions are made that largely dictate the economics of the project. The industry has been adopting Information Technology tools like Building Information Model that provide both the owner and the 9
management organization with detailed specific information about the building, (http://www.enr.com/news/informationtech/archives/050121.asp). The object oriented database of BIM stores the detailed parameters and descriptions of the building components that could be used for construction as well as for maintenance purposes. If this database were well developed and were filled with cost data, BIM tools would enable the architect to forecast the total building cost at the earliest stages of its design where the cost saving potential is the greatest. BIM tools drive the cost of pre-construction services down and reduce the time needed for quantity take-offs, estimating, breakdown coding and scheduling only if compatible software were used by all players. BIM tools enhance the collaboration between the architect, builder and subcontractor and also change the deliverys way of design from manual (x, y, z, 1, 2, 3) alpha-numerical data (used in tables, take-off schedules and spreadsheets) and from (2D, 3D drawings) graphical data, to a 4D module in which the library (the components of projects module) provides breakdown coding (items and assemblies) and automatic quantity take-offs.
Using the same BIM by all involved parties of a project drives the intercommunication problems to be automatically reduced, if not completely solved. The design modifications resulting in change orders problems are instantaneously measured in terms of cost, tender, and planning schedules. All this would result in an ease to control the project, only if appropriate and well developed databases were have been used by the architect.
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1.2
Building Information Model (BIM) Tools
Currently, there are three major software providers of BIM in the construction
industry; AutoDesk, Bentley Systems and Graphisoft. However, the BIM answers the nature of planning and control functions that are made more challenging by the simultaneous nature of the design and construction, the current BIM software arent totally compatible with the needs of traditional estimating practice like cost/item, labor and production rates. BIM software like ArchiCAD and Revit, allocate the cost by coded construction elements and assemblies (i.e. wall, column, beam, floor, roof, window, door, etc.), and not by coded individual materials that form the assembled components. This limitation affects the role that the architect could play in managing the construction process, and opposes to the Architect/Master Builder concept; the two previous BIM software do not integrate with any structural analysis software which conclude in reducing the role of the structural elements in the model to strictly illustrative. This inadequacy limits also the efficiency in calculating the quantity take-offs of wall, floor and roof components such as wood/steel studs, CMU/brick blocks, blue boards, tiles, paintings, carpeting, hardwood, shingles, etc. The new Uniformat II (ASTM Standard E1557) and Means Assembly Cost Data Manual provide Work Breakdown Structure (WBS) that is suitable for both schematic design and elemental estimate. Further explanation and comparison between the different coding systems and their uses can be found in Chapter 5: Database Organization, Formats and Coding Systems.
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1.3
Specific Objectives and Scope
This works main purpose is to identify both the advantages and limitations that
BIM technology brings to the Architect/Master Builder concept. The main focus is the support of BIM technology to the estimating practices and techniques. A secondary focus is the revolutionary approach that BIM introduces in terms of project planning and construction scheduling. It evaluates two BIM software in terms of ease of use, cost per element and different parameters within the central object database, different database organizations, rendering features and element ID record within the project-model, takeoffs reports and schedules, interface with other CAD software (Import, Export), integration with estimating software (like Timberline through ODBC) and project planning (like Primavera P3 and Microsoft Project). It didnt explore any integration with Structural Analysis Engineering software nor with Cost Control and Document Management software.
1.4
Methodology
Currently, there are many computer aided design software that use 2D&3D
platform. The most dominant software in the construction industry is AutoDesks product-the famous AutoCAD. At different design stages, the contractor uses different corresponding techniques and tools, as well as suitable software in which the cost data resides. In other words, the design documents are reviewed separately from the design platform. The efficiency of this process depends immensely on the intercommunication among the involved parties. Some technology limitations affect the interoperability such as electronic file exchange, scope definition and different database organization 12
(Uniformat vs. Master Format). The new BIM technology presents more advantages in that regards than the traditional CAD software. This thesis experimental research part consists of: Building a warehouse project using two BIM tools; AutoDesk Revit and Graphisoft ArchiCAD. Comparison between the two BIM; their features, ease of use and databases structures. Working with CSI-Master Format and Uniformat II coding systems using the two BIM tools. Exploring the two BIM tools' possibilities of integration and interface with other software used by estimating discipline.
1.5
Results
BIM is promising to reshape the way construction industry is functioning today.
The use of BIM Technology by the architect is going to result in fewer design documents, and in better communication environment. However, a new education for the architect is required, and investments of time and money are essentials. The implementation of advanced technology in the designing firms will provide an improved end product in the programming stage of a project, with no loss of design professional as an independent advisor and agent, and with no reduction in design quality and creativity. BIM generated documents are the end products of an attempt to provide other players involved in the project with a Design for Production. The contribution of BIM technology to the design is discussed in Chapter 2: Architectural design process.
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Chapter 2.
Architectural design process
Architecture by definition is the art or science of building; especially, the art of building houses, churches, bridges, and other structures for the purposes of civil life (Websters 1913 Dictionary). It is the discipline dealing with principles of design and construction and ornamentation of fine buildings; architecture and eloquence are mixed arts whose end is sometimes beauty and sometimes use (WordNet Dictionary). In other words, architecture deals with all aspects of life and intersects almost all fields of human endeavor. The size of projects and construction organizations has increased as well as the technological complexity level. This increase has resulted in more complex interdependencies and variations in the relationships among its organizations and institutions, and proliferating regulations and demands from government.
2.1
Construction Delivery Systems
Construction by definition is in a more general sense, frame or structure,
workmanship (Websters 1913 Dictionary). Construction approach and project nature have a strong effect on the design process and it delivery way during the project life cycle. There are four major construction approaches: Traditional (Design-Bid-Build), Turnkey (Design-Build, Design-Manage), Owner-Builder (Develop; Design-BuildManage), and Professional Construction Management (GC, CM). The three following figures (Figures2, 3, 4) are borrowed from the book Professional Construction Management by Donald S. Barrie and Boyd C. Paulson (page 27). The 14
Architect/Master Builder concept is in between two approaches; Owner-Builder and Turnkey.
Traditional
Owner-Builder
Owner
Owner
Designer
General Contractor
Design Department
Construction Department
Subcontractors
Own Forces Work
Contractors and Subcontractors
Optional Own Forces Work
Separate designer Single general contractor Numerous subcontractors Fixed price, unit price, guaranteed maximum, or cost plus a fixed fee construction contract Negotiated professional fee for design services.
Owner responsible for design and construction Optional own forces work contractors and subcontractors Fixed price, unit price, or negotiated construction contracts
Figure2. Traditional Contractual approaches
Turnkey
Design-Build Owner Engineer Contractor Design General Contractor Design-Manage
Owner Engineer Construction Manager Design Construction Manager
Subcontractors
Own Forces Work
Independent Contractors Single firm responsible for both design and construction Fixed price, or negotiated individual construction contracts Fixed price, guaranteed maximum, or cost plus a fee design-construction contract
Single firm responsible for both design and construction Specialty subcontractors Fixed price, guaranteed maximum, or cost plus a fee design-construction contract.
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Figure3. Turnkey contractual approaches
Professional Construction Manager
General Contractor Owner Design Design General Contractor Acting as Construction Manager Construction Manager Owner Construction Manager
A Number of Independent Contractors Subcontractors Three-party team of owner, separate designer, and general contractor acting as a construction manager Fixed price, or negotiated independent subcontractors Construction manager usually acting as agent for owner Negotiated professional fee for construction management services with cost reimbursement for subcontractors Negotiated professional fee for design services. Three-party team of owner, designer and construction manager Fixed price, or negotiated individual construction contracts directly with owner Construction manager may act as owners agent to extent delegated Negotiated professional fee for construction management services Negotiated professional fee for design services.
Figure4. Alternate contractual approaches
2.2
Design Stages, BIM Technology and Cost Estimate
In general, the design process has five stages; conceptual, preliminary design,
final design, tender preparation, and construction administration.
The Concept stage defines the scope of the project. It consists of all initial work on a project, from the identification of requirements to satisfy some perceived need, to selection of the most feasible alternative solution that meets those requirements, and to the decision to commit engineering and technical resources to the project design. BIM technology provides a quick visualization for alternatives. BIM has easy and simple features that 16
support building materials changes and different structural choices that range from wooden to concrete and steel.
The Preliminary Design phase involves preparation of outline drawings, choosing the desired construction materials, and performing other preliminary operations required to freeze the design. BIM technology makes design faster through the concept of automatic correlation; any change or design in one view is automatically updated in all sections, elevations, perspectives and even in the animated presentations of the project. BIM also facilitates design/build budgetary decisions based on preliminary or conceptual information.
At the end of the Final design stage, working drawings, technical specifications, and contract drawings are complete, and the project is ready to go to tender. BIM technology enhances the productivity of final design drawings and documentations because of the various objects parameters recorded in the model database. Actually, the design generated by BIM becomes the documents which quality differs from software to another. Documents quality depends on the amount of details and specific descriptions associated with the elements that form the parametric model generated by BIM tools.
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At the Tender Preparation stage, the project is in the hands of the contractors and the detailed, comprehensive pricing of the project is under way. BIM technology supports System Estimate, which is very helpful to develop accurate SF cost estimates and to verify Unit Price Estimates. A discussion about estimate practice is presented in Chapter3: Overview of cost estimating process.
During Construction, the contractors estimate is used as the standard to measure progress payments due; it can also be instrumental in the pricing of changes to the work. The designer is still present to respond to all Requests for Information coming from the job site as well as to make sure that the contractor is building what has been designed.
Although the degree of responsibilities of all the people involved in the project differs between the four approaches of construction, each method has its advantages and disadvantages for a particular application, and it has developed certain degrees of flexibility so that many of the alternatives overlap one another. However, a very good interrelationship between all members and excellent communications, leadership & human relations skills remain critical in order to meet quality, cost, and time objectives.
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Chapter 3.Overview of the cost estimating process
Estimate by definition is an approximate calculation of quantity or degree or worth; i.e. an estimate of what it would cost, a rough idea how long it would take Synonym: appraisal, approximation, forecast, gauge, and guess (WordNet Dictionary). It is to form an opinion of, as to amount, number, etc., from imperfect data, comparison, or experience; to make an estimate of; to calculate roughly; to rate; as to estimate the cost of a trip, the number of feet in a piece of land (Websters 1913 Dictionary). Project cost estimates have a tremendous role and a crucial effect during the life cycle of a project from conceptual to operational stage; it deals with costs in function of time, productivity, available resources and many other factors. Project management depends on the estimating techniques for best project control measures at each project phase till it is being constructed and it has been commissioned. Relative estimating techniques are used for feasibility analysis, financial requirements and approvals, budgeting, bidding and awards, warranty, maintenance and operation costs.
3.1
Estimating Techniques
Project phases, estimating techniques, and control measures taken by project
management are all linked in order to achieve the cost objectives. As mentioned in Chapter 2, five stages are considered: conceptual design, preliminary design, detailed design, tender preparation, project implementation and commissioning. Estimating techniques are categorized as: preliminary, unit price, elemental cost analysis, detailed 19
estimating, and updates (ref: Estimating: from concept to completion). A definite pattern of relationship exists between the project phases and estimating techniques. Figure5 illustrates the role of estimates in the project management environment (ref: Estimating: from concept to completion, p.4). In addition, project control measures such as project approval, budgeting and cash-flow forecasting, and cost control and corrective action have a distinct relationship with different estimating techniques.
Project Management
Project Control
Project Approval
Budgeting and Cash flow Forecasting
Cost Control and Corrective Action
Estimating cycle
Preliminary
Unit Price
Elemental Cost Analysis or Proposal Estimate
Detailed Estimate
Estimate Update
Project Phases
Concept
Preliminary Design
Detailed Design
Tender Preparation & Bid Analysis
Project Implementation & Commissioning
Estimating Concepts
Data Required for Estimating & it Sources
Factors Causing Variation in Estimating
Computers in Estimating
Modern Trends
Figure5. Role of estimates in the Project Management Environment
Most cost estimating techniques are developed by different construction team member on different cost estimating concepts, such as capacity at the conceptual design stage, functional analysis at the preliminary design stage, quantity takeoff at the detailed design stage, and method study at the tender preparation and construction stage. There 20
are four major types of cost estimating that are used in the construction industry. Every technique has a different level of precision in forecasting the cost during the estimating cycle. Preliminary estimate has 25% accuracy, elemental analysis estimate has 15% accuracy, unit price estimate has 10% accuracy and detailed estimate has 5% accuracy. The precision of an estimate is directly related to four factors:
1. The available data. 2. The time spent preparing the estimate. 3. The estimating technique used. 4. The skill and experience of the estimator.
Most estimates are based on historical data and on the experience of the estimators. Ten factors have to be considered every time before the implementation of historical or published data into a new project. These factors are: time, location, size and shape, capacity, number, quality, soil conditions, weather, competition, and local regulations (ref: Estimating: from concept to completion). The scope of the estimate indicates the amount and source of data used as the basis, that is, estimating guide used, previous project data, firm quotation, actual production labor hours, and so on.
As each phase of a project requires a different type of estimate, so each estimate requires different types of information and data. The precision of the estimate varies with the degree and quality of design/construction information that is available for use during its preparation. As the design progresses through each phase, more detailed information becomes available, and the estimate is increasingly reliable. 21
3.2
Role of Software to Support Cost Estimates Generated by the
Architect
Architects first responsibility is to meet the clients expectations in design quality as well as in budget. Widely used by architectural firms, 2D - 3D CAD software like AutoCAD, doesnt support any cost data storage on their platform. In order to generate the estimate, Architect/Engineer has to rely on other software. It could vary from a MS Excel spreadsheet or Lotus notes to a powerful Timberline spreadsheet. BIM technology presents a revolutionary approach in that regards. Both Graphisoft ArchiCAD and AutoDesk Revit have the cost feature allocated with the building elements (Figure6). However, the database structure is not the same in both software. The real challenge is to develop that library-database that contains both materials and labor costs and productivity information. Another challenge is the choice between the different work breakdown structures (WBS) and their different coding systems. CSIs formats are trade based while Uniformat formats are building based which makes it more suitable for BIM concepts. Chapter 5 will explicitly discuss WBS and the various coding systems.
CATIA was totally integrated with Pro-Engineer for structure analysis and calculations in FOGAs design of Experience Music Project (ENR 02/28/00 p. 76-83). The author of this work didnt explore the feasibility of BIM integration with other software used by structure engineers, and he is not aware of such feature. If such integration existed and the load calculation is automatically determined, the creation of a detailed elements database based on Uniformat II would be considered a very good investment of time and resources. BIMs duplication feature of library elements will 22
make the mission easy and feasible (Figure6). Why Uniformat II and not CSI? Because of Assemblies Cost Data, the publication of RS Means that provides building assembly and component costs that is suitable by both BIMs concept and by architectural practice. Then, BIM technology would be used to generate accurate estimating square foot costs, to compare building systems and to verify unit price estimates.
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Figure6. Library-Database in Revit (upper) and in ArchiCAD (lower)
With Object Oriented database and BIM approach, automatic quantity take-offs are instantly generated at any design stage. What does that means in terms of estimating techniques? How does this affect the project managements environment in general, and the estimating cycle in particular? How does BIM interface with estimating categories?
3.3
BIM, Estimating Categories and Project Management
Estimates are divided into four categories based upon different given information,
different purpose of usage, and different motivation and level of expertise. The four categories are order of magnitude, system estimate, detailed estimate and appraisals.
3.3.1 Order of magnitude (O/M) estimate
a. Factor estimate b. Elemental estimate c. Parametric estimate O/M estimates are used by owners to know: measures of revenue and cost/unit of revenue. The concept of O/M is to compare similar projects in different locations and time. The base is a historical data which could be statistical (Square Foot Cost Data, RSMeans), scientific (time study), and prototypical function data (experience). Actually, AutoDesk Revit has a limited feature in producing O/M estimates (Figure7). However, in the case of prototypical projects, BIM technology will save lots of time and effort through copy, cut, and paste features. Modifications and adjustments to previous 24
similar projects could be relatively easier than designing from scratch. BIM advantage is the model itself at that early stage of the project. Even though, detailed quantity take-offs would be available at that time, they have no relevance importance in terms of project budgeting. Newer versions of Revit (6.1 and above) do not longer support SF cost estimates that are based on R.S.Means Preliminary Cost estimates.
Figure7. AutoDesk Revit feature of generating O/M estimate
3.3.2 Conceptual estimates or systems estimates
a. Elemental analysis (to learn which element drives the cost up) b. Parametric estimating (the parameters of the building are used to produce an estimate for the project) c. Based on CSI (master format = trades-based building) or on Uniformat (system-based building) 25
d. Range estimate: mean value of the total estimates is equal to the sum of mean values (1). The variance is equal to the square root of precisions (2). To be able to reduce the range, we have to go back to our deviations and try to improve the level of precisions. Range estimates (statistical) are like Monte Carlo simulation of probability; they are used to produce the level of uncertainty and to defeat the cost overrun.
Systems estimates are mainly produced for value engineering practice. They are also used to help budgetary decisions and to prepare the documents for bids and contracts in Turnkey construction deliverys way. BIM technology is promising to reshape the construction industry in that regards through the schedule and cost report features. This would become a reality only if an accurate detailed database were well developed in BIM platform. Chapter4 would address database types and management.
3.3.3 Detailed estimate
They are based on the working drawings to produce a GMP contract or a hard Bid in a very competitive environment. Three formats are used: CSI format, Uniformat and Specs format. The major difference between the formats is the coding systems, and in consequences the costs allocation. An example of this difference would be concrete. In a Unit Price estimate, all the concrete items on a job would be priced in the Concrete section of the estimate; CSI Division 3. In a system estimate, concrete is found in a number of locations. For instance, concrete is used in all of these systems: Division A10, Foundations; Division A20, Basement Construction; Division B10, Superstructure, and 26
Division B20, Exterior Closure. A detailed description and comparison between the different formats would be found in chapter5 Database Organization, Formats and Coding Systems. Is it possible to link different WBS formats using only BIM platform? In one hand, AutoDesk Revit does not support multi-database concept. On the other hand, ArchiCAD supports multi-database concept. However, in order to be able to successfully link the different WBS formats, database should contain lots of details in their system assemblies. To summarize, BIM technology is not yet mature enough to support detailed estimates needs in a hard bid environment.
3.3.4 Appraisals
There are three methods to produce an appraisal: comparables (especially for houses), NPV of cash flow (for commercial properties), and replacement cost. Appraisals are used by funding organizations to know the cash flow and the value of the existing assets. BIM technology and architectural practice have nothing to do with this type of estimate, unless the cost of project element is recorded in a relevant and detailed way material cost, labor and installation costs. The recorded costs could be used as a reference for future replacement in a facility management environment.
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Chapter 4.
Database types and management
The database by definition is a set of related files that is created and managed by a database management system (DBMS). Today, DBMSs can manage any form of data including text, images, sound and video. Database and file structures are always determined by the software. As far as the hardware is concerned, it is all bits and bytes (http://www.answers.com/database&r=67) . (Figure8) is an illustration of the database.
Figure8. The Database
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Database is an organized collection of data, often created or manipulated with the help of a DMS. These data may be organized in several ways, but data structures that use relational tables have become the most common method for organizing and manipulating attribute data. Selections or queries are among the most common methods used to frequently identify and extract data that supports analyses conducted on attribute data. Relational tables are often placed in normal forms to improve correctness and consistency, to remove redundancy, and to ease updates.
A database typically contains complex structures, primarily to provide data security, stability, and to allow multiple users or programs to access the same data simultaneously. Database users often demand shared access, that is, multiple users or programs may be allowed to open, view, or modify a data set simultaneously. However if each program or user has direct file access, then multiple copies of a database may be open for modification at the same time. The database management system may act as an intermediary between the files and the application programs or user. The database management system may prevent errors due to simultaneous access.
4.1
Database Designs
Two database designs are currently finding significant application. First, network
database where each entity may be a node in the network and is connected as appropriate to other entities in the network. Network designs may be powerful and flexible. However, designing and implementing the network structure can be quite complex and 29
network databases are often difficult to modify. A great deal of information is stored in the complex network relationships, and updates require modifications of these linkages. Significant amounts of time, money, and expertise are usually required.
Object oriented database models are a second area that has received significant commercial interest in recent times. Object orientation has the ability to define classes of objects with values that are both private (restricted access) and public, and defines procedures or functions with the same name and general outcome, but which differ for each class of objects. Sub-classes may be derived from super-classes, and inherit some or all of the properties of the super-class. Object oriented designs have been described as more flexible and more easily understood and maintained, although there are relatively few successful examples of object-oriented spatial database management systems.
4.2
Database Management System (DBMS)
The approach of database management system -that best suits the construction
industry- should be the one that allows interfacing and integration between adopted software with minimum required human manipulation. In the market today, there is a wide variety of software that deals separately with design, cost estimate and subs, scheduling and planning, cost control and management, documents control and storage, and properties management. But very few are well integrated, either through open database connectivity ODBC, or directly between each other with few manipulations. However, many software providers have developed application software that is called a 30
package to deal digitally with some aspects of the industrys needs. Some packages overlap some areas, but still have to face the challenge of how to interface with the computer aided design systems. Information technology has succeeded to certain extent to link the cost estimating with scheduling, cost and document control. For more detail about this topic, please review Chapter6 - Overview of some available tools (Timberline, Revit, and ArchiCAD).
4.3
Object Oriented DBMS and Architectural Practice
What does object oriented DBMS can do for an architect? Would it be possible to
use old vector files like CAD drawings in BIM? What are the options to export from BIM to CAD software? Does BIM support the level of details required for shop drawings production? You own the data but will you always be able to access it? is the title of an article published by CAD Digest about Intellectual Property Rights in May 2003 (http://www.caddigest.com/subjects/autocad/select/croser_dwg.htm) . This article addressed architectural firms rights from a legal point of view that BIM developers have to take into consideration. At the same time of that year, an online debate between Bentley and AutoDesk took place on MSM. It was called The building Information modeling Debate Do You Develop on What You Already have or Do You Start Over? (http://www.msmonline.com/commentary/default.cfm?objectid=8EA3DC8D-475A40F2-B...). This debate addressed the integration and interface issue from a technical point of view. For more detail about this topic, please review Chapter6. What is sure about BIM technology today is that it supports multi-users environment through the team or team work feature. It allows multiple users to coordinate their design 31
instantaneously. Through multiple security access settings, design confusions and coordination problems are eliminated.
4.4
Current Estimating Practice
What does BIM bring to the estimators plate? How does it interface with the
contractors database? Does BIM support the contractors database life cycle? Before to answer these questions, lets have an overview of what is going on in current estimating practice. (Figure9) illustrates the database life cycle as it is utilized for best practice in the industry at the tendering and construction stages.
Quantities A n a l y s i s
Database
Unit price
Estimate
Analysis History
Accounting
Construction
Figure9. Contractors Database Life Cycle
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Eric Lamb, executive vice president of DPR Construction Inc., Redwood City, Calif., estimates the industrys 40,000 construction cost estimators spend 25% of their time, for an estimated 20 million hours per year, doing quantity take-offs. He estimates 75% to 80% of that labor could be avoided altogether if construction documents were circulated as 3D models built with industry-standard objects, instead of as plans and 2D views. This is a quote from an article published by ENR about Estimating and titled: Finding the bottom line gets a gradual life from technology (ENR/August12, 2002 /p.26-30)
4.4.1 Spreadsheets vs. Commercial Software Packages
Some GC estimators use a generic spreadsheet -30% use Excel of Microsoft, others use specialized estimating software -25% use Precision Collection of Timberline(CFMAs 2002 Information Technology Survey for the Construction Industry, published by the Construction Financial Management Association, Princeton, NJ. The complete survey is available at www.cfma.org). In general, the more conceptual an estimate is and the more complex the job, the more likely it is that an estimator will turn to the flexibility of customized spreadsheet that support the limited scope definition available at that stage (Square Footage estimates based on O/M techniques). The closer a job estimate gets to the final hard bid and the more standardized the work, the more likely it is that an estimator may opt for a commercial software package that supports the hard bid environment and last minute quotes from Subs. Many estimators still insist that you cant beat the classic spreadsheet-primarily Excel and Lotus 1-2-3- for flexibility, updating databases, report creation and customizing estimates to meet individual client needs. Spreadsheets can deal with uncertainties in the very early design stages when the 33
estimator is working from vague drawings and has to figure out what the designer has left out of the drawing. On the other hand, commercial packages serve a purpose, but people should realize that they will have to spend three to six months with one to four people to customize the data in these software packages. Commercial packages dont use parallel databases, but you can do that with spreadsheets. (ENR/August12, 2002 /p.26-30)
Packaged estimating application software users think that the package they use makes them more efficient for quick bid, and it is perfectly tailored to their needs. The estimating product gives a standard for everyone, is extremely efficient and accurate, and it produces very good reports that are useful for estimating and for communication with the field. Another important feature is that multiple users could work on an estimate simultaneously. The estimators concerns about software products are that they want them to integrate with project management and scheduling, and they want the ability to change the assumptions, such as work crew breakdowns and productivity rates, that govern calculations. Does BIM support that?
4.5
BIM and Database Management & Costs Updates
Quantities take-off process could be automated by the available BIM technology,
and this technology could improve industry efficiency significantly. Each take-off element has attribute data that includes dimensions, location, CSI or Uniformat codes, total cost estimate and descriptions (Figure6). However, as stated earlier in Chapter3, BIM does not support all the needs of estimators such as automatic update of the main cost database, the breakdown of work into tasks and packages, and the assignment of packages to individuals and organizations. In another word, current BIM technology 34
does not support in it platform the database life cycle, especially in terms of cost maintenance. It is designed more for architectural practice. What about BIMs interface feature with other estimating software?
4.6
BIMs Interface with Estimating Software
The export feature from BIM to estimating software application is limited at this
time, and it varies between different tools. While Revit has the option to interface through ODBC (Chapter 6), and the ability to generate customized templates spreadsheets in excel and text formats, ArchiCAD take-offs reports are in text format and excel only. Therefore, ArchiCAD feature that supports multi-database concept seams to be fruitless in terms of integration with other software used by different disciplines in the complex management environment of construction industry. More on that could be found in Chapter6 Overview of some available tools. What does BIM technology bring to the scheduling discipline?
4.7
BIMs Interface with Scheduling Software
In terms of schedule, current BIM lacks the feature to interface directly with
scheduling software -such as Primavera Planner P3 and Microsoft Project- which deals with tasks, not elements. However, BIM has a phasing feature which can be used to graphically illustrate the schedule, and to show the owner the schedule as a progressive model that enables simulation of the construction process. BIM does not support Critical Path Method network as produced by most scheduling software. However, Kathleen Liston a 4D consultant who helped Walt Disney Imagineering develop InviznOne 35
software- says schedule data can also be imported from various platforms such as Primavera Project Planner and Microsoft Project, as well as generic text files. Each activity in the schedule can be linked with one or more corresponding objects in the 3D model, enabling the construction sequence to play out like a movie (ENR/February 25, 2002 /p.29-31). The article title is Building Digitally Provides Schedule, Cost Efficiencies. In this article, there are many stories about how efficient BIMs phasing feature is in terms of reducing the number of potentially costly change orders. Chapter5 Database Organization, Formats and Coding Systems will address the role of work breakdown in the projects life cycle, the different formats and the importance of codes as glue that ties together the different disciplines of the construction industry.
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Chapter 5.
Database Organization, Formats
and Coding Systems
A construction project may be any undertaking, large, medium, small, or mega sized. Too many difficulties are depicted during construction and the risk of cost overrun is always present due to many factors (Michael Putzer wrote a feature article titled So, the Budget Ran OverBecause? that was published by Cost Engineering Vol.37/No.7 July 1995). Project management discipline has introduced five systems as tools for solving problems and controlling work and cash flow during pre-construction and construction stages of a project. These systems are: Project Definition System (for scope & budget development), Work Breakdown System (for task & budget development), Organization Breakdown System (for package & cost development), Project Budget and Cost Control System (for scope and budget control), and Project Planning and Schedule Control System (for time control). Computer Systems and tools have a tremendous role to play in the project, but every system has it application. The key role for the project manager is to coordinate these systems in order to improve communication and to make them a tool to serve the production-construction.
The database organization has to well respond to the life cycle of the project. Therefore, coding or numbering systems are the invisible glue between data. There are three major formats used by the building construction industry that assign alpha- numeric codes to categories and numeric codes for items and quantity take-offs. These formats are: Construction Specifications Institute (CSI-Master Format, 16 divisions) -Appendix 37
A, Uniformat 1 (12 divisions) -Appendix C- and Uniformat 2 (8 divisions) -Appendix D. A new outline of Master Format 04 was furnished for information purpose only by CSI on March 25, 2004. It contains 50 divisions -Appendix B. This outline is not to be considered a final draft or official publication of the Construction Specifications Institute.
5.1
Database Organization and Coding Systems
An alpha- numeric coded list of organizations (information and person of contact)
is supported neither by AutoDesk Revit nor by Graphisoft ArchiCAD platforms. It is created in outside platform as a separate file, and has the ability to be tracked by some other compatible software. The same thing is for the resources costs and crews productivity data. A coded cost data could be created and divided under five categories:
1. labor cost/each (not supported by BIM) 2. labor cost/crew (not supported by BIM) 3. material cost/each (questionable support by BIM) 4. material cost/assembly (supported by BIM) 5. subcontractor cost/lump sum (not supported by BIM)
5.1.1 Database and Construction Systems
The project planning and scheduling system is not a stand-alone system. A scheduling activity derives from the other systems. An effective schedule is a combination of activities, events, milestones, and timeline targets. Each activity has a project definition code, a functional organization code, a cost number, and single time 38
duration. The activities are developed through the project WBS of typical project phases. The cost number assigned to each activity comes from the cost estimate -the discipline responsible for cost accuracy. Cost estimating and budgeting is driven by definitions of functions and elements, by the breakdown of work into tasks and packages, and by the assignment of packages to individuals and organizations. The process leads to more accurate cost pictures at each transition point. Project Cost and Expenditure Control System requires that the project scope be maintained throughout each stage and must be able to relate to all interested project participants. This is achieved through breakdowns and codes that capture cost at its source and deliver the information to the corporate financial manager as well as to the project manager responsible. (Figure10) illustrates the role of codes as glue between all data used in construction project systems from estimating, to scheduling, to construction management.
R e s o u r c e s
Estimating
O B S C o s t
Code
C o d e
Cost Control
PM
Construction Management
WBS
Code
Cost
Schedule
OBS
Resources
Scheduling
W B S
Figure10. Code-Glue used by different management systems 39
At the tender stage, detailed estimating files are created. Since the estimate could contain elements and assemblies of elements, their codes could fall under many formats (CSI and Uniformat). Than the interface takes place with scheduling. Since the schedule contains both hard tasks that have direct cost and soft tasks that have indirect cost, it becomes necessary to group different tasks into group tasks that have their own codes. Than the interface takes place with construction management and document control. Since the bid packages contain several group tasks, these packages have their own codes, too. The resources assignment are easily linked and identified from the organization breakdown structure (OBS) codes. All kind of reports to track the resources productivity, to control their project cost and to communicate between all participants in the project, could be easily generated with the usage of the appropriate software without the need for another database. The project functional organization alpha-numerical code is used as a cost code. (Figure11) illustrates the project code structure based on functional organization as a cost code (George Suhanic Computer-Aided Project Management, page 135).
Organization Code (Alpha-Numeric)
X / XXXX / XXXX / XXX
Contract or Organization Code (derives from the package code). Purchase Order #, or Internal Journal Entry Voucher #, or Work Order #. Contract or Organization #, and Subcontract #. Cost Source (type of contract, P.O., J.E.V., ETC)
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Figure11. Project cost code structure based on functional organization
5.1.2 Database Formats and Published Cost Data
As stated earlier in Chapter3, The major difference between database formats is the number of divisions, the components code or numbering systems, and in consequences the cost per component or per measurement unit. Actually, this difference is coming from different ways to interpret a building. In one hand, Construction Specifications Institute (CSI) has produced a Master Format that consists of 16 divisions for the work breakdown. It is trade based format that suits the construction process. It gains a big importance for the reason of it familiarity within the contractors and the manufacturing industry. A new Master format 04 has been developed and the CSI-16 divisions has been expanded to become 50 Divisions.
On the other hand, the General Services Administration (GSA) and the American Institute of Architects (AIA) had jointly developed the original Uniformat 1 that consists of 12 divisions in 1972. It is building based format that suits the building system. It is mainly used by the architects for estimating and design cost analysis. The new Uniformat 2, first issued by ASTM in 1993, is an enhanced version developed by a task group that included amongst others CSI, GSA, American Association of Cost Engineers (AACE), The Tri-Services, R.S. Means and Canadian Institute of Quantity Surveyors (CIQS). It is more comprehensive than the original, particularly with respect to the mechanical and site work (http://www.constructioneducation.com). It consists of 8 divisions and the group of associations who had worked on developing it believes that it 41
suits better the projects life cycle from early stages, and in which the elemental design estimates will be consistent from phase to phase.
5.2
Quick comparison between database formats
The coding or numbering systems range from numeric to alpha numeric and the
code structure grows as long as we move between the five data levels from divisions, to sub-divisions, to group elements, to sub-groups, to elements. For example, a subdivisions code under (CSI-16) will look like this: 14200 Elevators in which the first two digits indicate that it is in division 14 Conveying Systems. The new CSIs Master format code consists of six digits instead of five, and it will look like this: 142000 Elevators. This sub-division code will be different under Uniformat 1, and it will look like this: A7.1 Elevators in which the letter A stands for assemblies and the number 7 for conveying systems division. Under the new Uniformat 2s numbering system, it will look like this: D1010 Elevators and Lifts as a group elements, in which the letter D is designated for Services division and the combination D10 is designated for the Conveying sub-division. (Figure12) represents level 1 numbering systems in CSIMaster format, Uniformat 1 and 2. Appendixes A, B, C, and D at the end provide levels 1, 2 & 3 numbering systems of a full constructions database. In the published Cost Data books, cost is generally recorded at level 5 the element level but in Square Foot Cost Data where the cost is recorded at level 3 of Uniformat 1 & 2 only. During the projects stages, cost data is used in all formats in order to meet the needs of everyone involved in the project. The real challenge for BIM technology is either to provide the ability to link different formats numbering systems, or to stick to the new Uniformat 2s numbering systems as AutoDesk did with REVIT. Another challenge is whether or not, it is feasible 42
to provide the ability to record all cost categories - labor, materials, and equipments - in BIMs platform itself with object oriented database where import feature is very limited to CAD files.
Master Format (CSI-16 divisions) 00 Conditions and Requirements. 01 General Requirements. 02 Site Construction. 03 Concrete. 04 Masonry. 05 Metals. 06 Woods and Plastics. 07 Thermal and Moisture Protection. 08 Doors and Windows.
Uniformat 1 (12 divisions) - Project Description. A1.0 Foundations. A2.0 Slab on Grade. A3.0 Superstructure. A4.0 Exterior Closure. A5.0 Roofing. A6.0 Interior Construction. A7.0 Conveying. A8.0 Mechanical System. A9.0 Electrical.
Uniformat 2 (8 divisions) - Project Description. A Substructure. B Shell. C Interiors. D Services. E Equipments and Equipments. F Special Construction and Demolition. G Building Site Work. Z General.
09 Finishes. A10.0 General Conditions. 10 Specialties. 11 Equipment. 12 Furnishings. 13 Special Construction. 14 Conveying Systems. 15 Mechanical. 16 Electrical. 43 A11.0 Special Construction. A12.0 Site Work. A13.0 Miscellaneous
Figure12. Level 1 numbering systems of Databases components
5.2.1 CSI Master Format and RS Means Building Construction Cost Data
Many Cost Data publishers have used the Master format numbering system in their books. One is the book called Building Construction Cost Data (BCCD) published by RS Means. It is the most used, most quoted, most respected unit price guide available to the construction industry. It is the professional estimators first choice for reliable unit costs. (RS Means, BCCD 2003). It is widely used in construction cost information for general construction. Installation costs are broken down into labor and equipments costs and are recorded at level 5 element level - with 12 digits referential numbering system. It provides access to thousands of materials and labor prices. All costs records are based on a National Average Cost. BCCD supports crew-based, hourly and unit-cost methods of pricing. (Figure13) is an illustration of the combined CSIMaster format and Means numbering systems used in BCCD to provide unit price. Appendix E is a page from BCCD-RS Means (http://www.rsmeans.com)
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Figure13. Levels 1 to 5 numbering systems for unit price line item
5.2.2 Uniformat 1 & 2 and RS Means Square Foot Cost Data
Square Foot Costs (SFC) is the name of the book published by RS Means that used Uniformat 1 numbering system of 12 divisions. Besides the cost per SF, It includes nearly 6,000 assemblies driven by unit quantities, from concrete footings to mechanical and electrical systems. After the release of Uniformat 2, new updated versions of SFC books are published using the new numbering system. Appendix F illustrates a sample page of the new SFC release in which all BCCD items are included. A new book was born in RS Means family; Square Foot & Assemblies Estimating Methods (SF&AEM). It provides RS Means labor and equipment costs, and formulas at the item level that allow for automatic calculation of quantities. It supports three pricing methods: unit cost, hourly, and crew. It is an essential reference for anyone who creates conceptual, construction, or appraisal estimates. The updated edition explains how to develop accurate and verifiable estimates with a minimal investment of time. (http://www.rsmeans.com) 45
5.2.3 Uniformat 2 and RS Means Assemblies Cost Data
Assemblies Cost Data (ACD) book is another member of RS Means family. It is used by construction professionals for quickly and accurately estimating square foot costs and verifying unit price estimates. (RS Means, ACD 2004). It provides thousands of building assembly and component costs. It is used by A/E/C for a quick system estimate and for easy comparison between alternative solutions and prices. It is also used for a quick check of a unit price estimate or subcontractor proposal. ACD has accompanying drawings, explanations, component breakdowns based on Uniformat 2 numbering system, and reference tables that are illustrated in Appendix G. Tables of unit prices allow costing out virtually any combination of building components or assemblies in the logical sequence of how the building is built. (Figure14) is an illustration of the combined Uniformat 2 and Means numbering systems used in ACD to provide unit price. Appendix H is sample pages that illustrate how Uniformat 2 links schematic phase elemental preliminary project descriptions and design estimates, in an effort to prove that Uniformat 2 facilitates design/build budgetary and value engineering decisions based on preliminary or conceptual information (http://www.rsmeans.com).
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Figure14. Levels 1 to 5 numbering systems for assembly price line item
47
Chapter 6.
Overview of some available tools
(Timberline, Revit, and ArchiCAD)
Information Technology has been improving the construction industry for many years. Emails substitute fax, FedEx expedite delivery of documents, and laptops are used with remote connectivity. Day after day, the contractors are getting away from paper and going into electronic communication. Too many benefits and promises are resulting from the implementation of IT, such as having instant updated information instead of periodic updated information. By definition, Information Technology (IT) or Information and Communication Technology (ICT) are the technology required for information processing. In particular, the use of electronic computers and computer software to convert, store, protect, process, transmit, and retrieve information from anywhere, anytime(Wikipedia-web dictionary).
The process of selection the proper software isnt simple or easy, if the objective is to implement integrated information systems within the organization. Training sessions are essential and key for a successful implementation of new software. The ROI (return of investment) study is substituted by the principle of making the same margin of profit after adopting the new system. Not everyone is capable to be on the leading edge, because it requires lot of investments and researches. Therefore when mistakes occur, this organization may suffer financial problems and ends on the bleeding edge. Electronic documents and electronic data are vulnerable. Software liability is only limited to the cost of the license. Litigation issue is present when the software is wrong, 48
which results in loss of time and money at the court. The life span of software is five years. The average spending on IT is between $2500 and $ 3500 per employee.(David Duttons lecture @WPI on April 15, 2003 course CE584; Advanced Cost Estimating)
6.1
Information Systems (IS)
Since IT is the development, installation, and implementation of computer
systems and applications(http://www.answers.com), Information System (IS) is a business application of the computer. It is made up of the database, application programs, manual and machine procedures and encompasses the computer systems that do the processing (computer desktop encyclopedia). The department of defense (DOD) define IS as the entire infrastructure, organization, personnel, and components that collect, process, store, transmit, display, disseminate, and act on information. (Figure15) illustrates the relationship between the systems.
Figure15. Relationship Between Systems 49
6.1.1 Management System in the Construction Industry
To resolve the project delivery difficulties, the Construction Industry has developed five project management systems that suit the life cycle process by which projects are conceptualized and eventually started up. In his book - Computer-Aided Project Management - George Suhanic defines the systems as the following:
Project Definition Structure (PDS) is a systematic means to establish project scope and quality parameters of elements as deliverablesit is the basis for the project code system. The earliest cost estimates and budgets are tied to it.(page 9)
Project Work Breakdown Structure (WBS) identifies project activities or tasks that create the PDS deliverablesWBS activities take on code numbers based on the structure, and become the code of accounts for estimates and budgets. The WBS budget is compared to the PDS as the first measure of project cost control.(page 9)
Organizational Breakdown Structure (OBS) aims to define and code the organizations and their project human resourcesevery element of project work ultimately has three code numbers, one for each of PDS, WBS, and OBS.(page 10)
Project Budget and Cost Control. Project budgets are based on estimates. Estimates are derived from scope and quality information set by 50
progressive developments in the PDS, WBS, and OBS exercisesthrough the use of codes, the final cost for an element may be referred to the initial budget for the same element. Constant comparisons of cost to budget provide the means for cost control.(page11)
Project Schedule and Progress Control. Time is of the essence in project workcomputer programs were written to process the results of Critical Path Methods (CPM) networks and convert the information to schedulesprogress control is achieved by ensuring that activities are carried out within the timeline.(page11)
The five systems aim to integrate project information into a common database to facilitate project control. The systems identify who does what, when, and for how much without the imposition of a rigid, hierarchical organization structure.
6.1.2 Information System in the Construction Industry
Information System (IS) in the construction industry means a Computer-Aided Project Management. IS uses a database of accurate information to define a project in language the customer can understand and the project team can use to deliver the finished job. IS ties in and integrates the five project management systems for scope, quality, cost, and schedule control, throughout the corporate functions. IS uses the project cost coding as a means to track the project scope from the time the project is known only by a ballpark estimate to when it becomes a definitive estimate, which forms the basis for project cost control. 51
6.1.3 Project Control System in the Construction Industry
A project control system is dependent on a range of management, corporate, and engineering systems and subsystems. (Figure16) illustrates the statement that a project control system is not a stand alone system. Other corporate systems are shown tying into project control, and project control feeds other corporate information needs (George Suhanic, CAPM, p. 246).
Figure16. Project Control System
6.2
Some available tools
Information Industry has developed different tools for different applications in
order to meet the construction industry needs. The real challenge for people around the globe is the integrated IT approach that suits the life of a project. For example, the 3D52
CAD is heading in developing new software which supports the standardization and the interface with estimating and scheduling. IAI, the international alliance for interoperability, and similar organizations are supporting the International Foundation Classes (IFC) files and Extensible Markup Language (XML) files which can be read by the majority of the software used in the A/E/C industry. Also, assemblies, models, check lists and online take-offs are all available tools for estimating at this time. Some companies, like Plan Well Enterprise, utilize the internet in the construction. They build project websites, display the drawings on the web before to bid them, order print out of the drawings, and submit your bid electronically. Other companies are working very hard to invent security software and tools like ID and password, digital thumb finger print, and so on, in an attempt to defeat hackers and to avoid their troubles.
Since database structures are diversified, and sometimes are not compatible with each other, integration and interface features between different systems were never easy or simple. Some companies have developed what is known as electronic office in order to solve integration issues in certain area of concentration. For example, Timberline office provides a platform that is compatible with both estimating and project control practices, and it also interfaces with scheduling software through export feature, and it supports ODBC concept. Another example, AutoDesk office provides a platform that is compatible with BIM, 2D-3D drawings and rendering. It also provides secure electronic communication where the project participants can share and store their documents. Maybe the simplest way to explain office concept is by using MS Office example; copy/paste feature is applicable in all Microsoft family members.
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6.2.1 Timberline Office Estimating (http://timberline.com/software/default.aspx)
Timberline Office estimating is a package database type. It is powerful software for Cost estimating using preset databases. These databases contain standard cost items used for takeoff, including item productivity factors, formulas and prices. Thus there is no need to type the same information again and again, as any information entered into a can database be easily retrieved. New items could be created, as well as new databases considering the particular needs and requirements of an organization, the zone or the location factor, or a particular type of a project. The estimates are presented in the form of Spreadsheets. These can be modified to show varying amounts of detail for presenting the estimates at various levels such as Corporate, Owner, and Project Manager. It enables to save all kinds of time, curb risk, and maximize profits by automating estimating and bid management processes. The core estimating application gets extra muscle from a full range of thorough databases packed with thousands of standard industry items that can be customized and used right away - or be enhanced with unique items, formulas, and factors. It is fully integrated with RSMeans databases and pricing services. Assemblies and modules in Timberline are formed from existing elements in the database, and their costs derive from the detailed prices of the components that form the assembly or module. Therefore the cost of assemblies generated in Timberline is more precise and relevant than the published cost assemblies data.
In the last couple of years, a new feature has been developed to add CAD integrator which enables Timberline to do fast takeoffs directly from CAD drawing files. 54
With the Timberline Office CAD Integrator, there is no longer need for a custom interface to transfer information from CAD drawings into a Timberline estimate since Timberline draws on the common information format of Industry Foundation Classes (IFCs), used to standardize CAD objects such as doors, windows, walls or HVAC ductwork. Estimates are generated directly from any IFC - compliant CAD software in a matter of minutes. Eliminating manual and digitizer takeoff means increased speed and improved productivity.
The following image has been taken from Timberline website and it shows the process of CAD integrating with IFC file.
Figure17. Timberline - CAD integrator with IFC file 55
Also Timberline Implements the use of WBS and OBS. However a PDS can not be created using Timberline, due to the quality and poor level of information available at early stages of the project. The Master format (CSI-16 divisions) is used to create estimates. The tasks are thus assigned WBS codes. The items can also be assigned to different geographical locations in a project. WBS codes allow organizing the estimate in a variety of ways - by project phase, drawing detail, or location. Timberline allows attaching up to 12 WBS codes to each item, which makes the analysis and reporting possibilities endless. Although, Timberline database is based on Master format, it provides a way to bind Uniformat and Master format together in one estimate using the phasing tool. It is very general sorting feature that links the coded level 5 items of CSITimberline to the not coded level 1 groups of Uniformat I or II. The following image has been taken from Timberline website and it shows the report that link Uniformat I to Master format.
Figure18. Timberline Uniformat I/Master Format phasing feature 56
Timberline also allows the assigning of various organizations or people to various different tasks. These can be used as the OBS, to show the responsibility for the various tasks. Timberline can create a wide range of reports - Standard Estimates, Field reports, comparison reports, Variance reports, bill of materials, whos doing what reports, crew reports, and many other reports related with the cost and the resources for the project.
Timberline has also developed an interface tool with TRA-SER. This software automates item pricing, giving the ability to import and update Timberline database with item pricing from the i2 Technologies solution - pricing service software for electrical, plumbing and HVACR components. The following image has been taken from Timberline website and it shows the interface with TRA-SER Pro.
Figure19. Timberline/TRA-SER Pro interface 57
Timberline has the ability to interface with industry-standard scheduling software such as Primavera - Project Planner P3 or Sure Track Project Manager - Microsoft Project for Windows. Scheduling Integrator provides instant access to labor and equipment details, material items, productivity factors, and estimator notes. The items from the estimate when exported to Primavera are assigned the WBS codes from Timberline as their Activity IDs. The WBS codes from Timberline can not be used for a WBS in Primavera unless a compliant WBS dictionary is preset in Primavera. Otherwise, new WBS codes and descriptions have to be created. The cost data and the resources for a particular activity are correctly transferred to Primavera. The following image has been taken from Timberline website and it shows the interface with Sure Track.
Figure20. Timberline/Sure Track interface 58
Timberline has developed an Open Database Connectivity (ODBC) feature that serves as a translator between different database file structures and other application software. The ODBC driver allows certain front-end applications to collect data from back-end applications. Because of ODBC, Access databases, Word processors and Excel Spreadsheets are able to communicate with Timberline.
In order to achieve a successful use of ODBC, one must first set up a Data Source Name (DSN) for each Timberline database to serve as a link with other applications. However, some steps are required to go from Timberline to Word passing by Access and Excel.
Step 1: Create an estimate in Timberline. Step 2: Extract the file from Timberline into Access. Step 3: Manipulate the file in Access. Step 4: Export the file from Access to Excel. Step 5: Export the Excel spreadsheet to a text file.
The communication between Timberline and Access is very strong; any change occurs in one file, the same change occurs in the other file in the second software. The level of communication between Timberline and Excel is reduced to one way; the change in Timberline affects the Excel file, but the reverse isnt necessarily true.
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Timberlines ODBC driver is limited in terms of importing. It only allows importing of some Invoices from Access into Accounts Payable. Records that are rejected by Import Invoices are copied to a separate rejected records text file. The Import Invoices journal lists any warnings and errors that occur during the import process. This information is used to edit erroneous information in the rejected records file. The rejected records file can be edited using any text editor that does not convert the file from the comma-delimited text format to a different format. After reviewing the errors on the Import Invoices journal and correcting the rejected records file, the file can then be used as the source import file when reprocessing rejected records. Each invoice that gets imported must have an invoice line APIF and a distribution line APDF. Just like entering an invoice manually, one first enters the invoice and then enters the invoice distribution information. The Access database has to be set up in a way required by Timberline needs. Two separate tables-one for APIF, and for APDF- have to be created in Access. They have to be exported through ODBC into a text file that Timberline can read. These two fields will be assigned WBS code and OBS code in Timberline.
6.2.2 AutoDesk Revit (http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=331041)
The AutoDesk Revit platform for building information modeling is a complete architectural design - as well as - documentation system supporting almost all phases of design and all the architectural drawings and schedules required for a building project. It is an object oriented database application that has a very easy way to obtain different building sections and elevations. Its library is full of standards items used for windows, 60
doors, furniture and utilities. Once a symbol is being inserted in any view - for example a plan view, it automatically appears in all other views of the project such as sections, elevations and 3D views. From massing and conceptual studies through the most detailed construction drawings and schedules, Revit helps provide better coordination and quality, and can contribute to higher profitability for architects and the rest of the building team. AutoDesk Revit has an export feature to AutoDesk AutoCAD, for the purpose of generating detailed workshop drawings. The communication between Revit and AutoCAD isnt strong; any change occurs in one file after the export is done, the same change doesnt occur in the other file in the second software. The import feature in Revit is limited to read AutoCAD generated files as reference drawing files only. This issue raised a debate between AutoDesk and Bentley systems in early 2003. I quote the following paragraph from a white paper published by Bentley Systems titled: Does the Building Industry Really Need to Start Over?
We believe that starting over with a new, incompatible platform (as AutoDesk suggest with Revit) in order to achieve these goals is dangerous, wrong and wholly unnecessary. This path has never been an option for our users there is simply too much investment and value in todays tools, data and workflows to throw it all away. Users with large investments and lots to lose from technology discontinuities demand and deserve a predictable and evolutionary path. Bentley has been and remains committed to providing an evolutionary path to our users. (Paragraph #6, page 3, does the building industry really need to start over white paper, Bentley Systems, January 2003 http://www2.bentley.com/industry_groups/default.cfm?objectid=7DC81D9D-2CBD-43..) 61
In the Revit parametric building module, every drawing sheet, every 2D and 3D view, and every schedule is a direct presentation of information from the same underlying building database that uses Uniformat II coding system (8 divisions). However Revit original database supports only the first three divisions. Revit provides the room and the tools to create new elements and families within the local database. Also, a wide web library is available for Revit users. The Revit parametric change engine automatically coordinates changes made anywhere. AutoDesk Revit supports some phases of the building process, preserving all information from beginning to end. The same model that is rendered in design generates quantities exported to an estimating database after construction documents are prepared. Revit stores the project data in one single central database in an attempt to provide one single design tool and database.
IAI and similar organizations are addressing the standardization issues by supporting the IFC and XML files which can be read by the majority of the software used in the A/E/C industry. However, Revit does not seem willing to address issues concerning interoperability in order to support these types of files. AutoDesks major concern is to extend Revits market, to reach competitors level of development and to have mechanical packages included in their program. Maybe Revits team feels that this can be overcome because other software in the A/E/C industry, like Timberline and Primavera, support IFC. Through the ODBC and CAD Integrator features, they can benefit from Timberlines research and results. However, the effective usage of Revit requires not only the knowledge of form and materials of the building, but also the knowledge of construction process. 62
Revit 6.0 has a clean and easy interface to pick up. As with most of the Windows based programs you have the usual File, Edit and Help pull down menu, and a second menu toolbar for Cut, Copy, Zoom and 3D etc. The remainder of the interface is then divided into two areas (Figure21):
- Design Bar with rollout functions covering Modelling (for most of the typical AEC and project based functions), Massing (for those feasibility studies), Documentation (schedules, text and drawing set-up), Detailing, and Edit.
- The Project Browser is similar in essence to an explorer type tree structure, allowing you to display all of the current, views, schedules, sheets and families active in the current project.
Figure21. Revit Design Bar and Project Browser 63
Revit has many advantages over other CAD software and that includes rendering; once you apply the type of material used during the design process, colors and landscape can be easily modified. Revit is very promising in order to achieve the aim of implementation of Computer Integrated Building Design. Revit provides a graphical/alpha-numeric data understandable by the all participants in the project life cycle. Appendix I (AutoDesk Revit 6 Features and Benefits) at the end provides information about Revit as integrated project model, and describes Revits features in terms of building design and components, powerful intuitive editing tools, site and landscape design, drafting and documentation, multi-user work environment, presentation and visualization, and reporting and data sharing.
Collaborative design can be achieved in Revit through its Project Sharing feature. There is a significant amount of pre-work that must be done in order for this feature to work among multiple project participants. Initially, until the project reaches a reasonable point of design, only one person can be responsible for the design development using Revit. Once design is at a point determined to be reasonable by Revit, Worksets must be created in order for the various components of the building to be sectioned off for multiple users in order for independent, simultaneous contributions to the design advancement to occur. These worksets allow for the controlling of the various stages of a projects development. A project manager can control who is working on what by only releasing worksets at particular times.
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A major issue that needs to be addressed in the initial project planning stages, especially in a design-build environment or one in which involves multiple locations responsible for design, is the computer networking among the participants. In order for Revits Project sharing to work, the central file, which coordinates and propagates the multiple changes by all users, must be centrally located and accessible by all who will be involved in the project. This becomes an especially daunting task when you can have multiple offices or multiple designers designing the various systems of any one project.
In terms of schedule, Revit -as all available BIM tools- lacks the feature to interface directly with scheduling software - such as Primavera Planner P3 - which deals with tasks, not elements. However, Revit has the 4D model feature which can be used to graphically illustrate the schedule. The phasing feature is an innovative way to show the owner the schedule as a progressive model that enables simulation of the construction process, instead of bar charts and CPM network as produced by most scheduling software.
6.2.3 Graphisoft ArchiCAD (http://www.graphisoft.com//products/archicad/)
Graphisoft develops software solutions for the design, marketing and maintenance of buildings. At the foundation of all Graphisoft products is the Virtual Building TM, a 3D digital database that tracks all elements that make up a building. The virtual building model makes it possible to administer and manage a building throughout its entire life 65
cycle. Graphisoft products range from Architecture design tools to rendering and facility management tools. The virtual building environment of Graphisoft supports open communication, modifications and enhancements to the design. Because file format compatibility is crucial, ArchiCAD provides the functionality to ensure that no data or time is lost in the conversion process. The DXF/DWG translator of ArchiCAD supports up to AutoCAD 2004 and accurately maps layers, pen colors, fonts and blocks. ArchiCAD can write out DXF/DWG data. ArchiCAD intelligent handling of AutoCAD Xrefs, at input and output, not only preserves the link but allows Xref administration (including linking, unlinking and binding) within ArchiCAD. In addition, ArchiCAD imports and exports AutoCADs vectorial DWF file format and Micro Stations DGN file format. ArchiCAD supports all major data exchange formats in use in the CAD industry and it supports International object standard, IFC 1.5.1, 2.0 and 2x (Phase 1 Certification) format.
Since 1996, Graphisoft has been a member of the International Alliance for Interoperability (IAI) that developed Industry Foundation Classes (IFC). The IFC concept is based on the idea of objects (or elements in ArchiCAD terms) brought together in an integrated model (ArchiCAD Virtual Building). IFC offers a higher-level common language for the sharing of intelligent objects between disciplines across the building lifecycle. IFCs object description protocol preserves the full geometric description in 3D, knows its locations and relationships, as well as all the properties (or parameters) of each object, such as finish, serial number and material description. The Geometry Description
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Language (GDL) object browser technology of Graphisoft allows information to be saved and transmitted in IFC format.
ArchiCAD provides complete plans, sections and elevations, architectural and construction details, renderings, animations and virtual reality scenes. It is fully integrated and provides quick and easy sun studies, fly-through and movies (Figure22). ArchiCAD automatically handles the documentation. It generates files that describe the design like bills of material and window/door/finish schedules. It records surface area and volume, thermal properties, room descriptions, price, and specific product information.
Figure22. ArchiCAD Design and Animation Tools 67
ArchiCAD supports team work environment through it collaboration functionality. Team work feature provides seamless communication for all the design development team using one platform. Individual security access with password system is available under team work feature. Also, ArchiCAD strongly supports the interoperability concept because it can read other CAD files and not stick to one solution only. The project resources can choose the combination of techniques those best suits both the specific task in hand and the available skills. ArchiCAD Internet enabled work flow management functionality provides a mean for electronic communication and design coordination.
In ArchiCAD, the parametric Virtual Building change engine automatically coordinates changes made anywhere. ArchiCAD has a central intelligent objects database as well as GDL objects library, and it supports multiple federated database concepts. The central object database (Figure23) is the core of the digital model; every element of the database has associated geometry, position per project, layer, pen color and architectural schedule code of three digits. The GDL objects library (Figure24) has more associated parameters and descriptors to its elements such as cost and material type and serial manufacturing numbers. The library manager engine supports the creation of multiple federated databases. ArchiCAD originally comes with CSI-Master format database (Figure25); the database supports three levels of components coding system. It also supports level four element coding under the descriptors field. Even though it supports multiple measurements units per database, only one unit could be assigned to one component one to one relationship. The cost is considered as a measurement unit. 68
Figure23. ArchiCAD Central Objects Database
Figure24. ArchiCAD GDL Object Library 69
Figure25. ArchiCAD Databases in Active Libraries
New
Edit
Link
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Figure26. ArchiCAD Link Central Objects to Active Database By Criteria
The link feature between the central objects library and the federated libraries is located under calculate tool of ArchiCAD (Figure26); it links object properties of the first to the component criteria of the second one by one. The same model that is rendered in design generates quantities exported as text and/or excel document after construction documents are prepared.
In terms of schedule, ArchiCAD also lacks the feature to interface directly with scheduling software - such as Primavera Planner P3 - which deals with tasks, not elements. Like Revit, ArchiCAD has the 4D model feature which can be used to graphically illustrate the schedule and electronically simulate the construction process.
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Chapter 7.
Case Study
The Construction industry has been adopting Information Technology tools and has been regulating the use of Building Information Model in the public sector. BIM provides both the owner and the management organization with detailed specific information about the building, but how effective and useful is this information? Could BIM really reshape the construction industry? How valid is the claim of BIM developers about enabling the architect to forecast the total building cost at the earliest stages of its design? What are the contributions of BIM in estimating field? This case study aimed to find some answers using two different BIM tools - Revit and ArchiCAD, as well as to unfold the capabilities of interface and integration features among different software and systems.
7.1
Methodology
This case study is based on the use of two BIM tools - AutoDesk Revit and
Graphisoft ArchiCAD - and all the steps taken to manipulate the database within BIM platform. It also encounters the integration with estimating and scheduling software.
The following steps were taken in AutoDesk Revit, Timberline and Primavera Planner: Building a warehouse project using AutoDesk Revit for ease of use assessment and proficiency evaluation purposes.
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Working with object parameters and creating new fields for estimating purposes.
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Using a model built by AutoDesk and it customized spreadsheets for analysis purposes.
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Creating an ODBC file for integration purposes. Using ODBC feature in Timberline for estimating purposes. Interface between Timberline and Primavera for scheduling purposes. Using Critical Path information in Revit for construction simulation purposes.
The following steps were taken In Graphisoft ArchiCAD, MS Excel and MS Project: Building a warehouse project using Graphisoft ArchiCAD for ease of use assessment and proficiency evaluation purposes. Creating Uniformat I and II databases in ArchiCAD Libraries for estimating purposes. Linking elements parameters from the central objects database to the components of the federated databases for estimating purposes. Creating an Excel file format of the take-offs schedules. Interface between MS Excel and MS Project for scheduling purposes. Using Critical Path information in ArchiCAD for construction simulation purposes.
One thing to note is that this research didnt explore any cost control neither any structural engineering software. 73
7.1.1 First Scenario: AutoDesk Revit
Many and different steps took place within Revit platform. The major focus was to manipulate the parameters of the elements that form the warehouse project. The goal was to improve the detail level of cost per element. The research attempted to find a way that supports the interoperability concept needs. The following list describes the actions performed by the researcher and records some particular steps in detail. 1. While using Revit to build the warehouse project, the researcher customized the line style, line weight and line properties (Figure27) Setting Pull down List. This customization of color line and style played a tremendous role in terms of visually illustrating different objects in 2D and 3D views, and in terms of easing the selection process of different elements for phasing and construction simulation purposes (Figure27).
Figure27. Revit Settings Pull Down List 74
2. When the digital model was done, the focus had shifted on working with object parameters and creating new fields for estimating purposes. Revit database is structured on Uniformat II coding systems. The database provides a cost field per element as a type parameter (Figure28) Element Properties. New shared parameters were created and saved in separate files as a text documents. The new groups of parameters were given names like CSI master format Group. New parameters were created under every group (Figure29) Project Parameters.
Since Revit allows the user to add parameters to the database categories per project, two new groups of parameters were added to all categories. The parameters values were stored as type parameters and not as instance parameters (Figure29).
Uniformat II Assembly Codes were selected correspondingly from the pull down list (Figure28), and the Assembly descriptions were automatically assigned to the elements as type parameters.
The new field parameters from the shared parameters groups were filled manually. Since Revit elements are assemblies, and in order to dissect the assembly into its components, couple selected elements - wall and column were provided by two sets of new codes that included costs 1&2 fields. However, all the cost fields were not filled because they wont have relevant reflection to all the cost categories required by the estimating discipline. 75
Figure28. Revit Element Properties
Figure29. Revit Project Parameters 76
3. AutoDesk Revit team has developed template reports to serve estimating and value engineering practices. The team has exported these templates into MS Excel and manipulated the information in the spreadsheets. Mr. Ken Stowe from AutoDesk has passed the work to the researcher who did a thorough examination of the displayed info in the spreadsheet. The first finding was that there was no tag to identify each element of the project. Apparently the assembly code alone is not enough to serve identification purposes. The same assembly code was used as a reference to each element of the same category i.e. B2010156 = Exterior, Brick CMU - (Figure30).
Figure30. Revit Template Report exported into MS Excel
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4. After some of the parameters fields - type and instance - were filled, ODBC driver in Revit was used to create data readable by Timberline. Data Source Name (DSN) was assigned to the new data. The researcher didnt expand his work to include the use of ODBC driver in Timberline. However, he did present this feature previously while giving an overview of Timberline software (page 55 of this report).
5. Timberline could open DSN file, but the information was similar to the one in the template report; no tag to identify the elements of the project. It was kind of impossible to benefit from the volume and area calculations generated by Revit since only type parameters were transferred by ODBC (Figure31).
Figure31. Revit - Multi category Schedule into MS Excel 78
6. In a separate research path, an estimate was created in Timberline. An interface with Primavera Planner was run to generate a work schedule and to assign work packages to sub-contractors.
The Activity IDs in the schedule were a direct correlation to the Timberline estimate. The Activity IDs were based on the appropriate division and phase of the CSI 16 divisions of Timberline. A 5 day work week calendar with holidays loaded was created. A basic WBS breakdown was created to create 5 subsections of the warehouse. Common types of work were grouped within the same WBS section. Each subsection was then broken down further in order to visibly reflect the work flow of the project (Figure32). A section preceding the subsections was created to track the goals and milestones of the project.
Figure32. Primavera Planner generated work schedule 79
Cost accounts were then created in Primavera, based on the CSI -Master format codes, to provide a correlated tie-back and reference to the Timberline estimate. Resources were then assigned as determined by the estimate for labor, material and equipment.
7. The Critical Path of construction was determined by Primavera. This information was used as a base for the visual construction simulation in Revit. Creating the 4D model -time is the fourth dimension- was a straightforward task as repeating the same steps multiple times at each level of the project in Revit. The same plan has three phases: existing, work in progress (demolition) and new construction.
7.1.2 Second Scenario: Graphisoft ArchiCAD
Many and different steps took place within ArchiCAD platform, too. The second scenario had the same major focus and primary goal as the first scenario. The following list describes the actions performed by the researcher and records some particular steps in detail. 8. While using ArchiCAD to build the warehouse project, the researcher wants to record that his use of layers combinations of color, style, weight, and material in the different plans views (Figure33) was mainly for visual display purposes. However, the layer setting is kind of neat; it duplicates the plan drawings in a fraction of a second with the flexibility to hide or add elements from or to the project respectively. Every element has many parameters that range from geometry and positioning to labels and listings (Figure34). 80
Figure33. ArchiCad Layers Settings and Combinations
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Figure34. ArchiCad Objects parameters and layers 9. When the digital model was built and after the struggle with the positioning feature of ArchiCAD, the focus had shifted on creating two federated databases - Uniformat I and II - in ArchiCAD Library (Figure35). To create a database, click on the calculate tab and choose edit database. ArchiCAD has originally two databases; one is called default and the other one is called AC 8 US. They are both based on CSIs Master format coding system. The database has a tree structure that provides two levels -keys and componentsthat is combined with descriptors level for components.
Figure35. ArchiCad Federated databases in active libraries
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The researcher has assigned level 1 coding to the keys and level 3 coding to the components in the databases. Level 4 coding was assigned to the descriptors. Also, he has created a list of units (Figure35). In order to make the new databases active in the library, he used the library manager feature from the file pull down list. He selected them and imported them into the project (Figure35).
ArchiCAD provides the user with the power to customize the lists or schedules of elements, components and zones of the project through the setting tool. It has also default settings for all the lists. (Figure36) illustrates two text formatted ArchiCAD schedules which are relative to the selected database from the libraries of the project.
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Figure36. ArchiCad Full Door Schedule (upper) and Basic Element Schedule (lower) 10. After the completion of the digital model, the researcher has explored ArchiCAD feature Project Publisher (Figure37). The user could publish a part of or the entire project to a public folder within the companys network provided by the option of choosing the display format of the documents.
Figure37. ArchiCad Project Publisher
11. After linking elements parameters from the central objects database to the components of the federated databases (Figure26), couple schedules were successfully exported into MS Excel. 84
12. Since estimating software that could import Excel spreadsheets -like Questhas not been available for the researcher, no work in the estimating field has been done after this point under the second scenario. However, since all Microsoft products are compatible with each other, selected fields from the exported Excel spreadsheet were copied and pasted into MS Project in order to generate the project work schedule.
13. The Critical Path of construction was determined by MS Project. This information was used as a base for the visual construction simulation in ArchiCAD.
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Chapter 8.
Results (Accomplishments,
Testing and Limitations)
The case study has - to some extend - touched the role of BIM technology in all stages of the projects life cycle passing by collaborative design to scheduling and documents control. However, the area of concentration was the contribution of BIM to the estimating discipline and practice.
8.1
Accomplishments
In terms of design, there is no doubt that BIM auto correlation engine enhances
the productivity of construction documents. Still, the production of detailed drawings solutions vary between Revit and ArchiCAD.
In terms of estimating, the two BIM tools differ between each other. The following is a separate presentation of accomplishments in Revit 6.0 and ArchiCAD 8.1.
8.1.1 First Scenario: AutoDesk Revit 6.0 and estimating
Few accomplishments in estimating have been made using Revit 6.0; adding parameters to the project as type and instance was beneficial but not totally successful when transferred through ODBC engine; ODBC could transfer only the type parameters of the project.
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Since the particular object information like ID tags, surface and volume are stored under instance parameters in Revit 6.0; ODBC feature was kind of useless, and the promise to integrate with Timberline -estimating software- has faded.
New fields were created under instance parameters like ID tags and costs. The cost fields were filled manually based on RSMeans Assemblies Cost Data book and on lots of assumptions made by the researcher on construction materials. Since Revit 6.0 stores the rendering information in different place than instance parameters, these assumptions were not maintained every time a change in construction material has occurred during the rendering process, because the rendering feature in Revit 6.0 is not linked to the object instance parameters.
In addition, Revit 6.0 supports only the level 3 in Uniformat II coding system, while the cost of materials is recorded under level 5 in the cost data books in order to provide enough fields of different cost categories such as labor, material and installation costs.
Finally, the template reports generated by Revit 6.0 team could benefit the total cost of material for a given project, but they are not relevant to the specific needs of estimators when a change order occurs during the construction stage of that project.
8.1.2 Second Scenario: Graphisoft ArchiCAD 8.1 and estimating
Some accomplishments in estimating area have been made using ArchiCAD 8.1; creating 2 federated databases for Uniformat I and II was successful in ArchiCAD 8.1 87
platform. The Codes and Descriptions data were entered manually in the system as well as the list of units and were stored under its own database separately.
The newly created databases were successfully imported to the warehouse project of the case study. The warehouse projects elements parameters, which are stored in the central object database, were linked to the components -the second level of the federated databases tree structure.
During the process of building the warehouse model, detail construction materials were selected separately and were related to the specific element of the building model. This information was automatically assigned an ID and was the basis for the automated rendering.
When the elements schedules were generated, the rendering information like ID and finishing materials fields were generated side by side to the location, number, dimensions, quantity, and surface fields.
Two types of elements schedules were generated; full door schedule and basic element schedule. Also, three components schedules were generated; one based on CSIs master format, the other two based on Uniformat I and II respectively. No zones schedule was generated. P.S. Elements, Components and Zones schedules represent the terminology used in ArchiCAD 8.1.
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The schedules generated by ArchiCAD 8.1 are in rich text format. Their quality doesnt support the need of powerful estimating software like Timberline. However, they were successfully exported into MS Excel. Since other estimating software that could import Excel spreadsheets -like Quest estimator that is distributed by RS Means- has not been available for the researcher, no further work in the estimating field has been done by him.
8.2
Testing and Limitations
The project final cost in estimating discipline is the final outcome of a function
with multiple factors and some assumptions. The project size and shape have an effect on the bottom line as well as the location, time and quality of construction materials. Also, production and labor rates vary between crews as well as the equipments costs. In a competitive environment like bidding a job, cost is neither a simple elements parameter nor a single measurement unit. The following is a recording of some BIM limitations in that regards.
8.2.1 First Scenario: AutoDesk Revit 6.0
When the new cost fields were created manually in Revit 6.0, they were treated as elements parameters. Revit 6.0 doesnt support a tree structure in its fields which results in no support for multiple categories that contribute to that particular element cost such as labor, material and equipment costs.
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When Revits team created their templates reports as a way around the issue, the reports didnt connect to the actual model when a change in the design occurred. The templates were not secured and were acting independently like customized spreadsheets; the change in the reports didnt result in a change in the model. Also, in order to update the data in the reports after a change in the design, new schedules have to be generated and be manipulated again.
The fact that Revit 6.0 doesnt support a tree structure in its parameters database, but it only provides multiple one line as parameters, has a tremendous effect on the codes needed by estimating discipline beyond the automatic level three Uniformat II code that is automatically assigned to the models elements. As previously presented, all factors of elements cost are recorded at level 5.
Not only the cost factors are not supported by Revit 6.0, but also the detailed components of the walls, ceilings and structures are not either. Revit 6.0 doesnt generate the number of studs in the interior walls, nor the number of panels, or concrete masonry units (CMU blocks), or bricks. It deals with the finishing materials only as a rendering feature and as a presentation tool.
Moreover, Revit 6.0 doesnt carry the type of reinforcing steel for concrete structures. The researcher finds that if we can not extract that information in a way or another from the model, it means we can not use it for estimating purposes where reinforced concrete structures are used in a project. Furthermore, BIM technology becomes no much different from the first generation of CAD in regards to estimating. 90
8.2.2 Second Scenario: Graphisoft ArchiCAD 8.1
Graphisoft ArchiCAD 8.1 went a step further than AutoDesk Revit 6.0 by supporting level four in the coding system within their database platform. Nevertheless ArchiCAD 8.1 supports multiple measurement units per database; only one unit could be assigned to one component-one to one relationship. The cost is considered as a measurement unit in ArchiCAD 8.1. If the cost value was assigned to level four and not to level five in the database, this value is insufficient for cost estimate discipline.
If ArchiCAD 8.1 could support the very detailed level of design (like AutoCAD and SOFTPLAN) within its central database platform, than the matter of supporting level five in the federated database would not have been an item on the issues list.
Like Revit 6.0, ArchiCAD 8.1 doesnt support the cost factors or the very detailed level of construction components like the walls, ceilings and structures. ArchiCAD 8.1 doesnt generate the number of studs in the interior walls, nor the number of panels, or concrete masonry units (CMU blocks), or bricks.
Moreover, like Revit 6.0, ArchiCAD 8.1 doesnt carry the type of reinforcing steel for concrete structures. The researcher finds that if we can not extract that information in a way or another from the model, it means we can not use it for estimating purposes where reinforced concrete structures are used in a project.
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8.3
Conclusion
The researcher concludes that the current stage of the two BIM tools on which he
based his work benefits most architects, facility managers and to some extend the construction managers. Since the needs of estimators and structural engineers are not completely supported, BIM technology developers have been competing to move the construction practice forward and to reshape the industry in the future. The author of this work is looking forward to that day when the Design for Construction is supported by BIM, and when total team collaboration for Production becomes reality in the digital century and Information Technology age!
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Chapter 9.
Recommendations
The construction peoples reliance on computer software has been tremendously growing in order to improve the efficiency of planning, building and managing a project. In the wooden framed residential construction industry, interoperability issue seems to be less complicated than in commercial and institutional.
Some CAD software like SOFTPLAN-Architectural Design Software provide the architect-designer with automatic wooden structure and wall frames generated from the plan views, as well as the exterior and interior perspectives, exterior elevations, and sections. It also supports the generation of detailed drawings for completed construction documents - Reference (www.softplan.com). Even though SOFTPLAN is not considered as BIM technology since it doesnt store the building information in a separate database, SOFTPLAN generates schedules of material in form of spreadsheets that could be used in excel as well as in HomeTech ADVANTAGE software which supports unit cost estimating system (www.HomeTechOnline.com).
Since MS Project is compatible with Excel and HomeTech ADVANTAGE spreadsheets, it would represent a good IT option to use in order to generate the critical path of the project work schedule. Many document control software are compatible with MS Project during the project life cycle which resumes in maintaining the needs of database life cycle maintenance of the architectural/construction firms.
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9.1
Recommendations
The Architect/Master Builder concept could be successfully supported by the
current IT for wood framed residential industry. Nevertheless, commercial projects have different level of details and different construction materials such as concrete and steel structure and CMU blocks, construction IT major providers are still working hard to develop a solution that supports the commercial buildings life cycle needs. Graphisoft has announced the birth of new member in its family; the new software supports the critical path method in scheduling and integrates with ArchiCAD and ArchiFM. Bentley System has developed Bentley Structure (Micro Station Triforma) that complements Bentley Architecture. For future research in the BIM technology areas, the author of this work recommends exploring the following areas:
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Review Bentley systems products like Bentley architecture and Bentley structure.
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Explore the possibility of linking the rendering features -of Bentley and AutoDesk products- to the project database.
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Explore the possibility of either interface or integrate between Revit and ArchiCAD with any structural software.
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Explore Graphisoft newly released software for Critical Path Method Scheduling.
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Extend the work done in estimating using the schedules generated by Graphisoft ArchiCAD; i.e. Quest estimating software could import excel spreadsheets.
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Explore some Oracle database document control and management systems that reject the need for a coded functional organization structure.
Finally, some computer programming skills might be necessary to walk around and solve some obstacles that might encounter the future researcher/s in the way.
Good Luck!
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Appendix A
Master Format (CSI-16 divisions)
(http://www.bdcorr.ca.gov/cppd/construction%20grant/2001_construction_audit_guide/ht m_files/csi_divisions.htm) (http://tacoma.wpi.edu/masterbuilder/breakdown)
Breakdown Structure 0 - Conditions & Requirements 1 - General Requirements 2 - Site work 3 - Concrete 4 - Masonry 5 - Metals 6 - Wood and Plastics 7 - Thermal and Moisture Protection 8 - Doors and Windows 9 - Finishes 10 - Specialties 11 - Equipment 12 - Furnishings 13 - Special Construction 14 - Conveying Devices 15 - Mechanical 16 - Electrical
Categories
01010 - Summary of Work 01020 - Allowances 01025 - Measurement and Payment 01030 - Alternates / Alternatives 01035 - Modification Procedures 01040 - Coordination 01050 - Field Engineering 01060 - Regulatory Requirements 01080 - Identification Systems 01090 - References 01100 - Special Project Procedures 01200 - Project Meetings 01300 - Submittals 01400 - Quality Control 01500 - Construction Facilities and Temporary Controls 01600 - Material and Equipment 01650 - Facility Startup Commissioning 01700 - Contract Closeout 01800 - Maintenance
02010 - Subsurface Investigation 02050 - Demolition 02100 - Site Preparation 02140 - Dewatering 02150 - Shoring and Underpinning 02160 - Excavation Support Systems 02170 - Cofferdams 02200 - Earthwork 02300 - Tunneling 02350 - Piles and Caissons 02450 - Railroad Work 02480 - Marine Work 02500 - Paving and Surfacing 02600 - Utility Materials 02660 - Water Distribution 02680 - Fuel and Steam Distribution 02700 - Sewerage and Drainage 02760 - Restoration of Underground Pipe 02770 - Ponds and Reservoirs 02780 - Power and Communications 02800 - Site Improvements 02900 - Landscaping
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03050 - Concrete Materials 03100 - Concrete Formwork 03200 - Concrete Reinforcement 03250 - Concrete Accessories 03300 - Cast-in-Place Concrete 03370 - Concrete Curing 03400 - Pre-cast Concrete 03500 - Cementations Decks and Toppings 03600 - Grout 03700 - Concrete Restoration and Cleaning 03800 - Mass Concrete
04100 - Mortar and Masonry Grout 04150 - Masonry Accessories 04200 - Unit Masonry 04400 - Stone 04500 - Restoration and Cleaning 04550 - Refractory 04600 - Corrosion Resistant Masonry 04700 - Simulated Masonry
05010 - Metal Materials 05030 - Metal Coatings 05050 - Metal Fastenings 05100 - Structural Metal Framing 05200 - Metal Joists 05300 - Metal Decking 05400 - Cold Formed Metal Framing 05500 - Metal Fabrications 05580 - Sheet Metal Fabrications 05700 - Ornamental Metal 05800 - Expansion Control 05900 - Hydraulic Structures
06050 - Fasteners and Adhesives 06100 - Rough Carpentry 06130 - Heavy Timber Construction 06150 - Wood and Metal Systems 06170 - Prefabricated Structural Wood 06200 - Finish Carpentry 06300 - Wood Treatment 06400 - Architec...