RC Lecture 4 - TOPIC 5 PAD FOUNDATIONS LECTURE NOTES...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
CIVL2007 Theory and Design of Structures II RC Component (10 April 2007) page 77 TOPIC 5: PAD FOUNDATIONS - LECTURE NOTES - General A building is generally composed of a superstructure above the ground and a substructure which forms the foundations below ground. The foundations transfer and spread the loads from a structure’s columns and walls into the ground. The safe bearing capacity of the soil must not be exceeded, otherwise excessive settlement may occur, resulting in damage to the building and its service facilities (e.g. water or gas mains). It is important to ensure that settlement, either immediately after construction or during the intended life of the structure, will be uniform and acceptably small. Foundation failure can affect the overall stability of a structure causing it to slide, lift vertically or even overturn. The type of foundation selected depends on a number of factors, namely: circle6 the depth of soil to a suitable bearing stratum, circle6 the bearing capacity of the stratum, circle6 the type of soil, circle6 the proximity of existing structures and their foundations, and circle6 an assessment of relative costs. Some typical foundations are shown in the following figures. In general the design of foundations requires an understanding of the principles of soil mechanics. In this course, we will deal only with the design of simple pad foundations (also known as spread footings or isolated footings ) for an individual column. Pile foundations will not be covered. Reference will be made to the Hong Kong Code of Practice for Foundations (2005) throughout this lecture. The Code is available for viewing at: http://www.bd.gov.hk/english/documents/index_crlist.html
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CIVL2007 Theory and Design of Structures II RC Component (10 April 2007) page 78 Figure 1. Types of Foundations
Image of page 2
CIVL2007 Theory and Design of Structures II RC Component (10 April 2007) page 79 Figure 2. Types of Foundations (Warner et al. 1998)
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CIVL2007 Theory and Design of Structures II RC Component (10 April 2007) page 80 Figure 3. Types of Foundations (Wang and Salmon 1998)
Image of page 4
CIVL2007 Theory and Design of Structures II RC Component (10 April 2007) page 81 A spread footing is a generally a shallow footing usually made of reinforced concrete. It transfers load from column(s) or wall(s) to the underlying soil or bedrock. The load is spread over a larger area of ground than simply bearing the columns and walls directly on ground. Their design is dictated by several factors but most importantly the bearing capacity of the soil. Such foundations consist of strips or pads or concrete (or other suitable materials) and are common in residential and commercial structures. Bearing pressure The actual distribution of soil pressure on the underside of a spread footing will vary depending on its flexibility, position of load application, and the type of soil. To simplify footing design in practice, it may be assumed that the pressure is uniformly distributed or linearly varying (depending on the applied load) throughout the area of the base. This assumption normally gives a more conservative design. Negative soil pressures (tension) cannot
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern