单调与反复竖向荷载作用下无黏结预应力型钢混凝土框架受力性能试验研究

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。

Experimental study on behavior of unbounded prestressed steel-reinforced concrete frame under vertical monotonic and cyclic loading

Two prestressed steel-reinforced concrete (PSRC) frames with unbonded tendons were tested under vertical monotonic and cyclic loading to study the static and seismic behaviors. In addition, the behaviors’ differences due to the different loading form were compared to investigate the influence of cyclic loading on the mechanical properties. The result shows there is no obvious change after the frame cracks and it has a good capacity and ductility index, which is 3.36 under monotonic load. The hysteretic curve under cyclic load is relatively full and possesses a pinching effect, and the maximum energy dissipation coefficient is 1.36. Before the maximum load, stiffness, load and cracks of two frames are almost similar, during which stage the maximum crack width of the two specimens was 0.11 mm and 0.08 mm, and the degradation to frame resulted from the cyclic loading is not clear. After the maximum load, the capacity decrease of frame under monotonic load is slow, while the cyclic one is rapid. Moreover, the finite element analysis was made based on the OpenSEES and the calculation result has a good agreement with the test results.