Shaking table test of post-tensioned unbonded prestressed concrete hollow slab-column structures

A 1/4-scale specimen of four-story post-tensional prestressed concrete hollow slab-column structure was constructed. The parameters in this study included the dynamic behaviors of the elastic and elastic-plastic stages and the seismic responses of the structure under the different peak accelerations of El-Centro earthquake waves. The results of the shaking table test indicated that the structure performed well under seismic conditions but the lateral stiffness was low. In addition, the results show that the key effect on the seismic responses is the low-order vibration mode and the first order modal shape shows shear characteristics in the elastic phase for earthquakes of small peak acceleration. However, with the development of the cracks and the accumulative damage, the damping ratio of the structure increases significantly and the shear deformation of the first order modal shape becomes less significant. In consideration of the effect of the hollow slab on the stiffness of the structure, an improved theoretical analysis of spatial slab-strip-column frame is carried out to predict the seismic responses. The calculated results of the elastic time-history analysis with ANSYS are in good agreement with the experimental data.