Stability of imperfect prestressed stayed beam-columns under combined axial load and bending

Abstract

The instability of imperfect beam-columns with crossarms and externally prestressed cable stays under combined axial load and bending is investigated numerically, where the bending is derived from self-weight, uniform distributed load or end moments. In combined loading cases, the load-carrying capacities of pure compression and bending are adopted to normalize the axial and bending loads respectively. The ultimate load of the stayed beam-columns is evaluated by conducting nonlinear finite element analysis. It is found that compared to doubly-symmetric stayed beam-columns, the performance of mono-symmetric stayed beam-columns under combined loads are more sensitive to different loading and imperfection combinations. Moreover, the structural response under combined loads is strongly linked to crossarm-length ratio, and the moderate crossarm-length ratio can give the most favourable mechanical behaviour since it strikes a balance among structural reliability, load-carrying capacity and efficiency. These studies would enable design guidance for practice in future.