11 - Chapter-11 - Geometric Design Manual-2002 Chapter 11...

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Chapter 11 Geometric Design Manual-2002 Mass Haul Diagram Ethiopian Roads Authority Page 11-1 11 E ARTHWORK Q UANTITIES AND M ASS H AUL D IAGRAM 11.1 Introduction The topic of geometric design would be incomplete without a chapter devoted to the issue of earthwork quantities and a mass haul diagram. The careful attentions to limiting earthwork quantities through the preparation of a mass haul diagram are essential elements in providing the best-combined horizontal, vertical, and cross-sectional design. This is especially true when the design includes consideration of the least cost in relation to earthworks. Key terms associated with this process, as listed in Definitions, include: ¾ Borrow- material not obtained from roadway excavation but secured by widening cuts, flattening back slopes, excavating from sources adjacent to the road within the right-of-way, or from selected borrow pits as may be noted on the plans ¾ Waste- material excavated from roadway cuts but not required for making the embankment ¾ Free Haul- the maximum distance through which excavated material may be transported without the added cost above the unit bid price ¾ Overhaul- excavated material transported to a distance beyond the free haul distance ¾ Economic Limit of Haul- distance through which it is more economical to haul excavated material than to waste and borrow The steps involved in the computation of earthwork quantities and the development of the optimal mass haul diagram are: ¾ End area calculations ¾ Earthwork calculations ¾ Preparation of mass haul diagram ¾ Balancing earthworks using the mass haul diagram These steps are presented in the following text. Of note is the fact that most current highway design computer programs, including MX (MOSS), will produce the mass haul diagram as part of the output when typical sections and horizontal and vertical alignments are inputs. A final stage of geometric design is then usually to make adjustments to the alignments in the interests of balancing or minimizing the earthwork quantities. 11.2 End Area Calculations End area calculations are usually made by one of the following methods: 1. Planimeter Method - The original ground line and template section (cross section) must be plotted on grid paper. Centerline profile grade must first be calculated for each cross section station to determine the centerline reference of each template plot. Areas of cut and fill quantities are calculated using a planimeter, converted to square meters, and tabulated for each section.
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Chapter 11 Mass Haul Diagrams Geometric Design Manual-2002 Page 11-2 Ethiopian Roads Authority 2. Electronic Computer Method - This method is widely used due to its versatility and speed of calculations. The end area calculation on modern computer programs is an integral part of the alignment design program and shown on output listings along with the geometric of each section. 11.3 Calculating Earthwork
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11 - Chapter-11 - Geometric Design Manual-2002 Chapter 11...

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