Building Technology
Question1
The type of foundation used to support a building is dependent on the type of in-situ soil, the bearing pressure of that soil and the loads imposed by the structure on the soil. The Building regulations state that the minimum depth to the underside of a strip found is 0.45 for frost protection and this should be extended to 0.75 in clay soils, largely due to the water retention in these materials ( Osbourn and Greeno 2007). This depth is also required to protect the foundation from seasonal variations of moisture content in a clayey soil.
Figure 1 Strip Foundation (Chudley and Greeno 2005, p.63, figure 2.2.1)
A strip foundation is a continuous, longitudinal strip of concrete, which is designed to spread the load of the building through the walls to the subsoil below. As shown in the figure above, the projection beyond the face of the wall should be at least the thickness of the foundation, to comply with the building regulations. The spread of the strip foundation is dependent on the bearing pressure and shear strength of the subsoil, as well as the loads imposed by the building. The depth of the strip foundation is dependent on the strength of the foundation materials (Emmitt and Gorse 2010). Generally a strip foundation is constructed using a relatively wide trench of 500mm to 750mm wide, with a layer of concrete poured into the trench in depth of 150mm. This provides a relatively level base from which to construct the walls of a building.
Figure 2 Trench Fill Foundation (Chudley and Greeno 2005, p.107) A trench fill foundation is essentially a deep strip foundation; a narrow trench is dug, with the width only slightly wider than the walls. The trench is filled with concrete to almost ground level. The advantage of a trench fill foundation is that because the trench is relatively narrow it reduces the level of earthworks and excavation time compared to strip foundations. This construction method is relatively safe, since the trench is
The type of foundation used to support a building is dependent on the type of in-situ soil, the bearing pressure of that soil and the loads imposed by the structure on the soil. The Building regulations state that the minimum depth to the underside of a strip found is 0.45 for frost protection and this should be extended to 0.75 in clay soils, largely due to the water retention in these materials ( Osbourn and Greeno 2007). This depth is also required to protect the foundation from seasonal variations of moisture content in a clayey soil.
Figure 1 Strip Foundation (Chudley and Greeno 2005, p.63, figure 2.2.1)
A strip foundation is a continuous, longitudinal strip of concrete, which is designed to spread the load of the building through the walls to the subsoil below. As shown in the figure above, the projection beyond the face of the wall should be at least the thickness of the foundation, to comply with the building regulations. The spread of the strip foundation is dependent on the bearing pressure and shear strength of the subsoil, as well as the loads imposed by the building. The depth of the strip foundation is dependent on the strength of the foundation materials (Emmitt and Gorse 2010). Generally a strip foundation is constructed using a relatively wide trench of 500mm to 750mm wide, with a layer of concrete poured into the trench in depth of 150mm. This provides a relatively level base from which to construct the walls of a building.
Figure 2 Trench Fill Foundation (Chudley and Greeno 2005, p.107) A trench fill foundation is essentially a deep strip foundation; a narrow trench is dug, with the width only slightly wider than the walls. The trench is filled with concrete to almost ground level. The advantage of a trench fill foundation is that because the trench is relatively narrow it reduces the level of earthworks and excavation time compared to strip foundations. This construction method is relatively safe, since the trench is
References: Acceptable Standards of Domestic Construction Committee NSW (2011). Acceptable Standards of Domestic Construction. [online]. Available at <http://acceptablestandards.squarespace.com/storage/asc9856-update-jan-13.pdf> [accessed 3rd June 2013]. Chew, M.Y.L. (2009). Construction Technology for Tall Buildings. Singapore: World Scientific. Chudley, R., and Greeno, R., (2005). Construction Technology. London: Pearson Education. Emmitt, S., and Gorse, C., (2010). Barry 's Advanced Construction of Buildings. Chichester West Sussex: John Wiley and Sons. Emmitt, S., and Gorse, C., (2013). Barry 's Introduction to Construction of Buildings. Chichester West Sussex: John Wiley and Sons. Fleming, I. (2009). Construction Technology: an illustrated handbook. Chichester West Sussex: John Wiley and Sons. National House Building Council (2012). Part 7 Roofs Chapter 7.2 Pitched Roofs. [online]. Available at <http://www.nhbc.co.uk/NHBCPublications/LiteratureLibrary/Technical/filedownload,45119,en.pdf?pending> [accessed 3rd June 2013]. Osbourn, D., and Greeno, R., (2007). Introduction to building. London; Pearson Education. Reid, E. (1984).Understanding Buildings; A multi-disciplinary approach. New York, NY: MIT Press. Smith, S., and Stronach, P. (1986). Builders ' Detail Sheets. Oxford: Taylor and Francis