既有预应力宽幅空心板受力性能的破坏性试验
Destructive test on mechanical behavior of existing？？prestressed wide hollow slabs

为了准确评估宽幅空心板构件的承载能力，以昌樟（南昌―樟树）高速公路改扩建工程为依托，对肖江大桥拆除的2片服役20年的预应力混凝土宽幅空心板进行原型试验研究。试验采用2个1 500 kN千斤顶，对空心板进行分级加载直至试件破坏，分析构件的破坏模式及加载过程中挠度、应变随荷载变化的关系；基于退化分层壳元法编程考虑材料、几何非线性的有限元分析程序，并应用该程序对试验全过程进行数值模拟。结果表明：构件破坏模式为顶板混凝土压碎，跨中截面形成塑性铰的典型受弯结构破坏；加载至构件开裂时，1号、2号梁的开裂荷载分别为360、320 kN，对应的实测挠度值分别为22、16 mm，加载至破坏时，1号、2号梁对应的破坏荷载分别为880、？？800 kN？？，对应的实测挠度值分别为556、540 mm，构件具有较好的延性性能；数值模拟计算的开裂荷载和破坏荷载分别为360、920 kN，为1号梁试验值的1.00、1.05倍，为2号梁试验值的1.13、？？1.15？？倍，数值模拟计算值与试验结果吻合较好，编程的有限元程序能较好地模拟预应力钢筋混凝土空心板的破坏全过程；由试验结果及理论计算得出，1号、2号梁的活载因子？？λ？？分别为3.16、2.77，安全系数？？S？？？？f分别为1.57、1.43，构件具有较好的承载力性能。？？
In order to accurately evaluate the bearing capacity performance of wide hollow slab, based on Changzhang Highway reconstruction and expansion project, a prototype test of two prestressed concrete wide hollow slabs in service for 20 years has been carried out with the opportunity of demolition and reconstruction of Xiaojiang Bridge. In this experiment, two ？？1 500 kN？？ jacks were used to load the hollow slabs until the specimens were damaged, the failure modes of the components and the relationship between the deflections and strains during the loading process were analyzed. Based on the degradation of layered shell element method, a finite element analysis program considering the consideration of material and geometric nonlinearity was compiled, and the program was used to simulate the whole process of the test. The results show that the failure mode of the component is crushed by the roof concrete, and the typical bending structure of the middle cross section is formed by the plastic hinge，the cracking load of No.1 and No.2 beam is 360 and 320 kN, the corresponding deflection is 22 and 16 mm respectively. While loading to failure, the failure load of No.1 and No.2 is 880 and 800 kN, the corresponding deflection is 556 and 540 mm respectively, which shows that the component has better ductility. The cracking and failure loads calculated by the numerical simulation are 360 and 920 kN, which is 1.00 and 1.05 times as much as that of the test value of No.1, 1.13 and ？？1.15？？ times as much as that of the test value of No.2. The numerical simulation results are in good agreement with the experimental results, which shows that the nonlinear finite element program developed by the authors can simulate the whole failure process of the prestressed reinforced concrete flexural members well, according to the test results and theoretical calculations, the live load factors of No.1 and No.2 beams are 3.16 and 2.77, and the safety factors are 1.57 and 1.43 respectively, indicating that the component has good