Shakedown seismic analysis of composite steel-concrete frame systems

The earthquake analysis of buildings and structures can be performed by finding solution of the optimization problem of shakedown analysis, which takes into account the nonlinear properties of materials. Such analysis has several advantages. External actions are introduced as the set of the load cases, that's why we can solve the problem for all direction of seismic load and for every scheme of live load at once. As part of the solution of the optimization problem we can take into account the nonlinear behavior of the elements. This paper presents the solution for shakedown analysis of buildings with elastic-plastic and brittle elements. It is assumed that the load varies randomly within the specified limits. These limits are determined by the possible direction and magnitude of seismic loads. The example of such analysis of system is introduced. Some attention has been paid to the practical application of the proposed mathematical model.