Calculation and design methods for shallow foundations due to TS 500

Turkish Standard that requirements for design and construction of reinforced concrete structures as TS 500 (2000) record that, the calculations and designs of foundations should be done as foundation elements on elastic foundations. In our country, lots of computer programs are used in engineering offices for calculations of foundation elements on elastic foundations. These programs generally use Winkler model for calculations of foundation elements on elastic foundations. In Winkler model assumed that, the soil originate with independent infinite elastic springs and settlement of subgrade at some point of its surface as proportional to the stress between the foundation and the subgrade at the same point. This method, is known that the common name which is used in our country as subgrade reaction approach. In analyses are done with subgrade reaction approach, computer programs want that modulus of subgrede reaction values an input from users. In Turkey, the values of modulus of subgrade reaction (bedding module) generally are taken from tables as soil physical quantity, which were published in native or foreign sources. But, for determining modulus of subgrade reaction, the stresses and the settlements which occur at the base of foundation must be calculated. For calculation of stresses and settlements which occur at the base of foundation, there are lots of factors are active, which are related with soil, foundation and superstructure. Because of this, the modulus of subgrade reaction is not a soil physical quantity. In this study, a method is proposed that involve factors acts for calculation of stresses and settlements for calculation of modulus of subgrade reaction due to rigid foundations which are supported by multi layered soil system. The calculations are done with proposed method, the settlements that occurs at base of foundation which are supported by multi layered soil system are calculated as converting single layered soil system. The converted single layered soil system involves equivalent layer thickness and equivalent constraint modulus. Besides in this study, a computer program is developed which can calculate the modulus of subgrade reaction for design and the settlements of rigid foundations which are supported by multi layered soil system.