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对两榀无黏结预应力型钢混凝土(PSRC)框架进行了试验研究,分别施加单调与反复竖向荷载,分析并比较不同竖向荷载形式下无黏结PSRC框架的受力特征及其差异,以研究反复荷载作用对其受力性能的影响。试验结果表明:无黏结PSRC框架开裂后刚度不发生明显变化,具有优良的承载力及延性,单调荷载作用下框架的计算延性指标约为3.36;反复荷载作用下,其滞回曲线较为丰满,呈现一定的“捏拢”效应,最大能量耗散系数为1.36;达到极限荷载前,两框架的刚度、所受荷载值及正向作用下的裂缝开展情况基本接近,力加载阶段框架梁上最大裂缝宽度分别为0.11mm和0.08mm,反复荷载对结构性能的退化作用不明显;极限荷载作用后,单调荷载下框架所受荷载下降平缓,而反复荷载作用下框架所受荷载快速下降,且随着变形增大,速度变快。基于OpenSEES程序对竖向反复荷载作用下的无黏结PSRC框架的受力性能进行了模拟,其荷载-位移计算曲线与试验结果吻合良好。
The experimental research on two-frame unbonded prestressed concrete (PSRC) frame was carried out. The monotonous and repeated vertical loads were applied respectively. The stress characteristics and differences of unbonded PSRC frames under different vertical loads were analyzed and compared. Influence of Repeated Load on Its Performance. The experimental results show that the stiffness of the unbonded PSRC frame does not change significantly after cracking, and has excellent bearing capacity and ductility. The calculated ductility index of the frame under monotonic loading is about 3.36. The hysteresis curve of the unbonded PSRC frame is full, A certain “pinch in” effect, the maximum energy dissipation coefficient is 1.36; before reaching the ultimate load, the stiffness of the two frames, the load value and the crack initiation under the normal action are basically close to each other, The maximum crack width is 0.11mm and 0.08mm respectively. The effect of repeated load on the degradation of structural performance is not obvious. After the ultimate load, the load on the frame under monotonic load decreases gently, while the load on the frame decreases rapidly under the repeated load As the deformation increases, the speed becomes faster. Based on the OpenSEES program, the force performance of unbonded PSRC frame under vertical cyclic loading is simulated. The calculated load-displacement curve is in good agreement with the experimental results.