U型粘钢加固预应力混凝土梁抗弯性能试验研究

为了探讨不同损伤程度、粘贴钢板厚度和高度、有效预应力大小和加载方式等对粘钢加固部分预应力混凝土梁抗弯性能的影响,进行2片普通钢筋混凝土(RC)梁以及8片部分预应力混凝土(PPC)梁的U型粘钢加固抗弯试验和数值分析。结果表明:采用U型粘钢加固部分预应力混凝土梁能够有效抑制裂缝的扩展,显著提高加固部分预应力混凝土梁的正截面抗弯承载能力;部分预应力混凝土梁损伤后加固,其屈服荷载和刚度较未损伤加固梁均有不同程度的降低;初始有效预应力水平主要影响使用阶段的抗弯性能;非线性有限元模型能够预测U型粘钢加固梁的抗弯行为,计算结果与试验结果吻合较好;在实际工程中建议梁侧面粘贴钢板高度不超过梁高的1/3为宜。

Experimental Study on Flexural Properties of Prestressed Concrete Beams Strengthened with U-shape Steel Plates

Transverse tests of two ordinary reinforced concrete(RC) beams and eight partially prestressed concrete(PPC) beams strengthened with U-shaped steel plates were carried out under static loads to investigate the influence of the damage degree,thickness and height of steel plates,magnitude of effective prestress and loading mode on the flexural performance of the PPC beams strengthened with U-shaped steel plates.Numerical analysis was also made.Conclusions are drawn as follows: The cracking development can be effectively restrained using the proposed method of strengthening with U-shaped steel plates,and the flexural load-carrying capacity of the normal section of the strengthened PPC beams can be effectively improved;compared with the PPC beams without damages before strengthening,the yield load and stiffness of the PPC beams with damages before strengthening are reduced to varying degrees;the level of initial effective prestress mainly affects the flexural behavior of the beams in the service stage;the nonlinear finite element(FE) model can be used to predict the flexural performance of the strengthened PPC beams,and the results well agree with the test results;in practice,it is suggested that the height of the bonded steel plates on both sides of the beams should not exceed one-third of the height of the beams.