The paper “ Design Requirement for Deep Footing” is a spectacular version of a lab report on engineering and construction. Deep Foundation is suitable when the soil top layer is soft and has good bearing soil strata. This means that it can withstand super-embossed stress. If the two mention conditions are made, then a deep foundation is used. In designing a footing for the story building various requirements need to be determined in order for the strong structural building. Among the requirements include a structure and loading capacity. Loading capacity is very important as it will allow the footing to withstand the maximum weight.
The soil shown from the well is soft at the top and has good bearing soil strata; it can as well withstand super-embossed stress. This soil provided requires soil is of high compressibility this calls for Punching shear failures and the initial will be as follows If the column is too tall it will be crushed under its own weight, therefore, the maximum height of the column is limited because of compressional pressure at the bottom cannot exceed the compressional strength of the material.
However, the maximum height at which a footing buckle is less than the height it will be crushed. In designing the footing, the sizing of the footing should be as shown below. Sizing the footing If the tensile or compressive stress exceeds the proportional limit of soil, the strain is no longer proportional to the stress. The footing will tilt when the strength as shown. If the stress exceeds the elastic limit, the material is permanently deformed. For still larger stresses, the solid fractures when the stress reaches the breaking point.
The maximum stress that can be withstood without breaking is called the ultimate strength. The ultimate strength can be different for compression and tension; then we refer to the compressive strength or the tensile strength of the material. A ductile material continues to stretch beyond the ultimate strength without breaking it; the stress decreases from the ultimate strength. Examples of ductile solids are relatively soft materials such as gold, silver, copper, and lead. These metals can be pulled like taffy, becoming thinner until finally reaching the breaking point. CalculationIn calculating the loading capacity, the footing a number of factors are taken into account.
These include; ultimate strength, the durability of the footing, serviceability, stability, and fatigue. Ultimate strength involves the determination of compressional capacity, tensional capacity, and lateral of piles. Compressional capacity involves the determination of geotechnical strength which is calculated by multiplying ultimate geotechnical with geotechnical strength reduction factor. The following table provides ultimate strength parameters for base bearing and skin friction. The table shows base bearing and skin bearing for the foundation of different soils. Material Base bearing kpa) Skin friction (kpa) XW rock 1500 60 DW rock 4500 200 DW/SW rock 7500 235 SW rock 1200 300 Active lateral pressure on piles is earth pressure on footing cause slight movement from the backfill.
In this case, the foot rotates about the bottom to take a new position which is tilted to the point of plastic equilibrium. It is recommended that the deep foundation used on the project designed in accordance with standard Pilling- Design, and installation. This code uses the limit state design method the following must be taken into account: -
Coduto, Donald, Man-chu Ronald Yeung, and William Kitch. Geotechnical Engineering: Principles & Practices. Boston: Prentice-Hall, 2010. Print
Lommel, John. Geotechnical Problem Solving. NEW York: John Wiley & Sons, 2012. Print.
Sivakumar, Nagaratnam & Braja Das.Geotechnical Engineering: A Practical Problem Solving Approach. New York: J. Ross Publishing, 2009. Print
Wyllie, D., 1999. Foundations on Rock: Engineering Practice. CRC Press, 1999.