预应力平行圆管混凝土空心板柱结构地震后承载力试验研究

建造了一个4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,分别进行地震前第3层楼板弹性范围内的荷载试验和地震后第1层楼板极限荷载试验,通过测量楼板挠度、钢筋应力及空心楼板的裂纹发展情况,探求预应力混凝土空心板柱结构地震的损伤破坏,楼板的承载能力的变化情况。试验结果表明,在相同荷载作用下,楼板跨中、平行布管方向预应力暗梁和垂直布管方向预应力暗梁跨中地震后挠度均大于地震前。空心楼板的整体性较好,强烈地震对楼板的刚度响应较小,楼面承载力试验过程仍可划分为三个阶段:弹性阶段,开裂扩展阶段和破坏阶段。地震对垂直布管方向预应力暗梁刚度影响大于平行布管方向预应力暗梁,垂直布管方向预应力暗梁跨中挠度地震后比地震前增大程度明显大于平行布管预应力暗梁。基于前述试验结果,并考虑空心楼板的裂纹发展情况,建立了空心楼板极限荷载状态下的塑性铰线分析模型,计算空心楼板的极限荷载略小于试验结果,计算结果与试验数据吻合较好。

EXPERIMENTAL STUDIES ON BEARING CAPACITY AFTER EARTHQUAKE OF POST-TENSIONED UNBONDED PRESTRESSED CONCRETE HOLLOW SLAB-COLUMN STRUCTURE

A 1 /4 scale four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the load test in elascity on the four-storey plate before a shaking table vibration and ultimate load test on the second-storey plate after the shaking table vibration.By measuring the floor deflection,stresses of steel bars and crack of hollow slab,the earthquake damage of post-tensioned unbonded prestressed concrete hollow slab-column structure and the bearing capacity of the floor are explored.The test results showed that the middle points deflections of hollow slab and beams in parallel and vertical direction the tubes of are larger after the earthquake than before the earthquake in the same load.The hollow floor has a good integrity,the influence of earthquake on the stiffness of the slab is very smaller.The bearing capacity tests of slab can be also divided into three stages: elastic stage,crack expansion stage and destruction stage.The influence of earthquake on prestressed hidden beams in vertical direction of tube are larger than the those in parallel direction of tube.The mid-span deflections of beams in vertical direction of tube are increased significantly than those in parallel direction of tube after earthquake.Based on the test results and in consideration of crack growth in hollow slab,a improved plastic hinge model is set up to predict the ultimate loads,The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.