后张无粘结预应力混凝土空心板-柱结构的振动台试验研究

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

通过一个四层现浇无粘结预应力混凝土空心板柱结构的1/4比例模型的模拟地震振动台试验,对其在弹性和弹塑性阶段的动力特性以及该结构在El-Centro地震波不同峰值加速度作用下的地震反应进行了研究。试验结果表明,现浇无粘结预应力混凝土空心板柱结构具有一定的抗震能力,但其抗侧移性能较差;对地震反应起控制作用的是低阶振型;在地震加速度峰值较小的弹性阶段,模型的一阶振型呈剪切形变形,随着裂缝的开展和损伤的积累,结构阻尼比显著增加,一阶振型的剪切特征越来越不明显。基于试验结果,并考虑空心管孔洞对楼板刚度的影响,建立了改进的空间框架"板带-柱"结构分析模型,通过ANSYS软件对该结构进行的弹性阶段时程地震反应分析结果表明,计算结果与试验数据吻合较好。

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 E1-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.