Beam Foundations after Kany and El Gendy

by Quick ELPLA

(Analysis and Design)

Part I: Numerical Models

Different calculation methods are known in the literature for the calculation of shallow foundations. The early one is that assumes a uniform contact pressure distribution under shallow foundations. This assumption is too far from the reality. Winkler (1867) and Zimmermann (1930) developed the modulus of subgrade method. In the method, the subsoil is simulated by isolated springs. The settlement of the spring is only dependent on the loading at the same point on the subsoil surface at the spring location. This also applies to possible refinements with springs of different stiffness.

However, Boussinesq (1885) had already recognized that when the subsoil is loaded at one point, the subsoil also settles outside the load point. Therefore, it does not behave like a spring. Because of this finding, Ohde (1942) developed a calculation method for the first time, with which shallow foundations can be analyzed, taking into account the soil structure interaction. This method, which is called modulus of compressibility method, was later further developed by different authors (Graßhoff (1966-1978), Kany (1974), Graßhoff/Kany (1992)). Quick ELPLA is based on the modulus of compressibility method after Kany (1974) and the modulus of subgrade reaction method after Kany/ El Gendy (1995). However, some refinements are included, some of which are new and have not yet been dealt with in detail in the literature. It is therefore necessary to explain the calculation methods in more detail than usual in order to be able to check the results and compare them with other results.