内嵌预应力螺旋肋钢丝加固混凝土梁预应力损失试验研究

Experimental study on the loss of pretressed for RC beams with prestressed near surface mounted helical rib steel wire

针对内嵌预应力螺旋肋钢丝加固混凝土梁技术特点,研发了预应力螺旋肋钢丝张拉锚固体系,测试并分析了试验过程中预应力损失情况。结果表明,预应力损失随螺旋肋钢丝加固量及初始预应力水平的增加而增加,其中锚具变形和预应力筋内缩引起的预应力损失很小,不超过5%,应力松弛引起的预应力损失相对较大,在5%-10%之间,放张引起的预应力损失大小介于上述两种损失之间,一般不超过10%,且加固量及初始预应力水平对该项损失的影响较显著。研究结果为该新型加固技术更好地应用于实际工程提供了设计依据。

Considering the characteristics of RC beams with pretressed near surface mounted helical rib steel wire,first develop the tension an-chorage system of pretressed helical rib steel wire,then test and analyze the prestressing loss of the experiment procedure.The results show that the increase of prestressing loss accompany with the increase of helical rib steel wire’reinforcement volume and the initial prestress level,the pre-stressing loss caused by the anchor deformation and the shrinkage of prestressed steel is small,which is not more than 5%,the prestressing loss caused by the stress relaxation is relatively large,between 5% and 10%,the prestressing loss which caused by releasing between the two losses is not surpass 10%,the influences which caused by the reinforcement volume and the initial prestress level is significantly.The study results provide the basis for the the new reinforcement technique which applying in the practical engineering.