Enhancing the robustness of steel-concrete composite buildings under column loss scenarios

Abstract

This paper investigates the robustness of steel-concrete composite building frames under column loss scenarios. Various composite building frame models, including different bracing systems, composite slab and joints are taken into account in analysing the dynamic response of the frame structure against the loss of a column due to accidental load. Robustness of ten-storey steel-concrete composite buildings with (i) diagonal braces at the corners, (ii) centre core wall, (iii) rigid moment joints are analysed for corner, perimeter and internal column loss. The analyses results show that simple braced frames are vulnerable to the progressive collapse compared with the moment resisting frames, which has higher redundancy to redistribute the loads arising from sudden column loss. Various strengthening approaches are investigated to improve the collapse resistance of the simple braced frames. Vierendeel truss was proposed at selected floor level in a building to redistribute the load due to column loss. End-plate or modified fin-plate connections were proposed for column-to-beam connections to enhance the progressive collapse resistance of simple braced frame. The resistance against progressive collapse is also investigated for building with outrigger-belt truss.