开裂预应力混凝土T梁的承载能力试验研究

Experimental Study on Bearing Capacity of Cracked Prestressed Concrete T Beams

通过对张拉前、后的预应力混凝土T梁裂缝进行观测,发现施加预应力对裂缝在中性轴以下的部分具有较好的加固效果.对开裂T梁与完好T梁的对比等效静载试验结果进行分析,结果表明:中性轴以上区域裂缝处的压应力越大,裂缝不可逆的闭合趋势越强;在2期恒载及运营期反复交通荷载作用下受压区的非受力裂缝可能自愈,表面处理后将不影响结构耐久性;非受力裂缝对于预应力混凝土T梁短期整体抗弯刚度无明显影响.最后指出对于开裂预应力混凝土T梁可以用等效静载试验方法或长期监测确定其承载力.

By means of observing the cracks of the prestressed concrete T-beams before and after tension,it is found that prestressing is of better reinforcement effect on the cracks below the neutral axis.The stronger the irreversible closure tendency of cracks is,the non-stress cracks in the compression zone may heal themselves under the second-stage dead load and repeated traffic loads during the operation period.After the surface treatment,the structure durability will not be affected,and the non-stress cracks have no significant effect on the short-term overall bending stiffness of the prestressed concrete T beams.It is pointed out that the equivalent static load test method or long-term monitoring can be used to determine the bearing capacity of the cracked pre-stressed concrete T beams.