PSI - Issue 48

G. Gusev et al. / Procedia Structural Integrity 48 (2023) 169–175 Gusev et al/ StructuralIntegrity Procedia 00 (2023) 000–000

171

3

2. Problem statement and solution methods Analytical models are used to describe the deformation of reinforced concrete elements as described e.g. by Tamrazyan (2022). However, numerical models, as described for example by Lazouski (2022), are more commonly used for this purpose. The problem of evaluating the stress-strain state in the system "building-foundation-soil mass" is divided into the solution of several boundary problems. Since one of the main parameters of serviceability of building structures under such conditions is the value of ground massif deformations in the vicinity of building foundations, the determination of relation between the value of these deformations and the structure's deformation state is basic in thiswork. At the first stage of the analysis, we consider a finite fragment of soil combined with the building foundations in the form of a slab. The boundary conditions simulate the situation when the structure is in the uniform field of tensile deformations in the near-surface layer of the soil mass. The stress-strain of the system "building - foundation - soil mass" is determined for different types of frameworks and types of foundations. Then, we evaluate the conformity of the stress-strain state in the bearing elements of the building framework with the soil mass deformation in the foundation vicinity, which simulates the effect of undermining on the structure. Deformations of the soil mass in the vicinity of the foundation are strictly normalized, so the search for its connection with the structure's SSS is essential for its safe operation. Then, it was decided to divide the general problem into subtasks, one of which was to simulate the deformation behavior of individual joints of the building's load-bearing structure and to work out a general strength evaluation criterion for this kind of structural elements. Two types of reinforced concrete element joints were singled out. On the basis of previous calculations, we selected variations of loading diagrams that correspond to deformation of the building under the undermining effect. A series of problems of determining the deformation behavior of concrete elements joints up to complete collapse have been solved numerically. The strength criterion which described by William-Warnke (1975) and Mises’s elastic-plastic flow model for steel reinforcement have been used to simulate the behavior of concrete structures. Ground conditions in terms of physical and mechanical soil parameters are assumed to be the same for all calculation models. 3. Results and discussion Based on the results of numerical solutions to boundary problems of modeling the deformation behavior of systems "building - foundation - soil mass", the distribution of stresses in the supporting elements of reinforced concrete frames depending on soil deformations in the vicinity of foundations of different types has been obtained.

Fig. 1. Third main stresses for the general building model.