In-plane stiffness of precast monolithic floor composite structures

The structural integrity of a steel frame–shear wall structural system with a precast floor cover was experimentally investigated. A test structure with a new precast floor (SJ2) and a test structure with a cast in situ floor (SJ1) were subjected to shaking table tests. It was found that the natural frequencies of both specimens were similar. Under the action of different levels of seismic waves, the new precast monolithic floor and the cast in situ floor maintained the transmission of seismic shearing forces, thereby allowing the lateral-load-resisting members to function co-operatively. The maximum inertial forces and storey shearing forces of SJ2 and SJ1 differed depending on the seismic waveform and seismic loadings and for different storeys of the structure; some were basically the same, but the value of SJ2 was larger than that of SJ1 under some conditions. The difference in the amount of deformation was small, except for the deformation resulting from El Centro 200 cm/s 2 , for which the SJ2-to-SJ1 ratio of in-plane stiffness was 0.65. Thus, the novel precast structure (SJ2) that meets the requirements of engineering design would be applicable to a multi-storey reinforced concrete structure located in a seismic region.