Comparative cyclic tests of exterior flat slab–column connections in normal concrete and fiber-reinforced lightweight aggregate concrete

Post-peak load ductility of connections in reinforced concrete structures is essential to ensure structural integrity against seismic action and also to prevent local failure, which may lead to progressive collapse. The purpose of this study is to evaluate how the addition of steel fibers to the concrete mix can improve the hysteretic behavior of exterior flat-plate slab-column connections. Experimental tests were carried out on four full-scale exterior slab-column assemblies, all with the same geometries, reinforcement layout and concrete compressive strength. Two reference specimens were cast in normal concrete, and two in lightweight aggregate steel fiber-reinforced concrete. Quasi-static reversed cyclic loading was applied to the specimens. Ductile behavior was observed for all connections, with a marked increase in drift capacity, ductility and dissipative capacity in those made of fiber-reinforced lightweight concrete. Moreover first steps towards the numerical simulation of flat slabs to columns structures are presented.