Stability of a Multistoried Building on a Ground Base Described by a Bilinear Model

Abstract

The paper uses computer programs based on the finite element method to study the problems of loss of stability and collapse of multistoried buildings located on weak soils with elastic-plastic properties. Such properties, in particular, can be shown by clay rocks, which are often found on construction sites and in conditions of overload and excessive moisture behave as perfectly plastic materials. A characteristic feature of these soils is the loss of bearing capacity, which is accompanied by a sharp decrease in the modulus of deformation. The problem is solved in a non-linear formulation using a bilinear model of the ground base that best corresponds to the analyzed computational situation. From the point of view of construction mechanics, the critical state of the “ground base – structure” system is considered as an indifferent state. In this situation, with small external forces, an unlimited growth of deformations is observed. From this point of view, the use of numerical research methods is very effective. To solve this problem, the perturbation theory is used in combination with the method of successive loadings. A multistoried building on a slab foundation is considered. A weak wind effect is used as a disturbance. Stepwise increase in the vertical load allows determining the critical reactive pressure in the base. Based on the results obtained, a variant of strengthening the foundation is proposed.