Comparison of Bearing Capacities for Strip, Square and Circular Shallow Foundations on Soils with Terzaghi Method by Calculating in Excel Program

Abstract

It is important to calculate the bearing capacity on soils for foundations since the majority of building foundations build up on soils. The failed application is usually due to the miscalculation and acceptance of the bearing capacity of the soils. Using many equations and parameters to calculate bearing capacities on soils for foundations causes errors, and difficulties in calculations, thus was more useful to calculate by Excel program.  In this study, it was aimed to compare the bearing capacity on soils for stripe, square circular shallow foundations by the Terzaghi method calculating the Excel program. For this, the parameters of width, length and depth of foundation, the cohesion, internal friction angle, and unit volume weight of soil, load slope angle and safety factor were used. The bearing capacity component values for the strip foundation from largest to smallest decreases as first, second and third component in bearing capacity equation. The component values in the bearing capacity equation for the square and the circular foundation decreases same as those for the strip foundation again although the amount varies.  The first values in the bearing capacity equation for square and circular foundations are the same and but in strip foundations it is smaller than those in square and circular foundations. The second component in the bearing capacity equation is equal in all types of foundation. The third component value in the bearing capacity equation decreases as those in strip, square and circular foundations, respectively. Their ultimate and allowable bearing capacities increase as those in strip, circular and square foundations respectively, although the amount varies. It is more appropriate to calculate the bearing capacity on soils for shallow foundations with the Terzaghi method at the beginning as it provides the first prediction. In conclusion, except for calculation with the Terzaghi bearing capacity method, individual other methods or the average of the entire methods of bearing capacity can also use according to the aimed structure.

Keywords: Terzaghi method, strip foundation, square foundation, circular foundation, ultimate bearing capacity, allowable bearing capacity, soil.

DOI: 10.7176/JEES/15-2-03

Publication date: March 30th 2025