Design-oriented nonlinear-elastic buckling analysis of reinforced concrete wall structures using convex optimization

摘要

The structural response of slender reinforced concrete (RC) structures may behighly nonlinear due to cracking, reinforcement yielding, and geometricallynonlinear effects. While advanced models can simulate the detailed responseof such structures, they are generally ill-suited for limit state verification inpractical design scenarios due to a high computational and modeling effort. Adesign-oriented method for evaluating the geometrically linear response ofcracked RC wall structures was recently presented and demonstrated to allowthe analysis of large-scale models with more than 2400 finite shell elementswithin minutes on a standard personal computer. This paper proposes adesign-oriented numerical method for efficient instability analysis of slenderRC wall structures, also enabling the inclusion of thermal effects. Based on atwo-step linearized buckling analysis, the method first determines the geometricallylinear structural response by solving the complementary energy minimizationproblem, including, if relevant, thermal strains and reduced materialstiffness. This solution is used to derive the sectional stiffness upon which alinearized buckling problem is formulated and subsequently solved as a lineareigenvalue problem. The model is validated using examples with exact solutions,and its applicability to large-scale models is demonstrated through anexample with a four-story stairwell modeled using more than 3200 finiteelements.