Performance of ductile RC flat slab to steel column connections under cyclic loading

This paper is concerned with the performance and design of a novel ductile structural steel shearhead for connecting reinforced concrete flat slabs to tubular steel columns. In the suggested system, a gap is left around the column to enable the slab to be connected to the column through isolated structural steel members which are designed to yield in shear before punching failure occurs. The proposed connection could serve as a primary lateral resisting system in regions of moderate seismicity or as a secondary system in areas of significant seismicity. The paper describes a series of large scale slab tests, as well as complementary component tests, which were carried out to develop the proposed shearhead system. The detail is shown to offer enhanced ductility and energy dissipation compared with traditional forms. Experimental and numerical results are used to demonstrate the favourable inelastic performance of the connection under combined gravity and cyclic lateral loading. Finally, recommendations suitable for inclusion in design guidance are presented and discussed for the proposed shearhead detail.