Ensuring safe operation of monolithic structures in undermined areas

In order to ensure safe operation of buildings in undermined areas, it is necessary to take into account the influence of loads extrinsic to typical structures. The solution of the generalized boundary value problem on the evaluation of the stress-strain state (SSS) of the building–foundation–soil system with due regard for the complete geometry and physically nonlinear behavior of all the elements is inexpedient since it is complicated by the large dimensionality of the problem. This paper discusses an approach allowing the state of monolithic reinforced concrete building structures located in an undermined area to be estimated by solving boundary value problems on different scales, from modeling the whole system in an elastic formulation to modeling joints between load-bearing members (columns and floors) in a nonlinear formulation for concrete and reinforcement. In these problems, strain energy is taken as the parameter characterizing the deformation process at critical deformation stages and connecting the boundary value problems. The obtained loading diagrams for a unit and the evaluation of the SSS of the whole structure enable one to find the values of maximum permissible horizontal soil deformations in the vicinity of the foundation, at which the bearing members reach the SSS preceding the loss of bearing capacity.