斜腹杆体外预应力对RC嵌固梁加固性能的影响

Influence of external prestress of tilt-bellied poles on strengthening performance of RC embedded beam

用理论分析、模拟分析和试验验证的方法,研究斜腹杆体外预应力对钢筋混凝土嵌固梁的加固性能.按照变形协调原理建立嵌固梁荷载挠度方程,得到对应预应力索-梁组合单元的力学模型.利用ABAQUS有限元模拟的方法研究不同设计参数对嵌固梁加固效果的影响次序.结果表明,索垂度显著、索初始预应力居中、索截面面积次之;斜腹杆体外预应力简支加固方法能提高试件的刚度、抑制试件塑性发展速度、改善试件的承载能力和延性,试件开裂荷载、屈服荷载、极限荷载明显提高,加固效果显著.选择3组各2个试件进行静力试验验证.在弹性阶段,理论计算和软件模拟所得荷载-挠度曲线与试验结果吻合;进入塑性阶段后,试件的理论值远大于试验值和模拟值;而试验值与模拟值始终吻合,模拟分析结果可信.

The reinforcement performance of external prestress of tilt-bellied poles for reinforced concrete embedded beam was studied by means of theoretical analysis,simulation analysis,and experimental verification.According to the principle of deformation coordination,the load deflection equation of the embedded beam was established and the mechanical model of prestressed cable-beam combination unit was obtained.The influence order of different design parameters on the reinforcement effect of embedded beam was studied by using ABAQUS finite element simulation method.The result showed that the cable sag would be significant,the initial prestress of the cable would be moderate,and the area of cross-section of the cable would be less.The simply-supported reinforcement with external prestress of tilt-bellied poles would be used to improve the rigidity of the specimen and suppress the plasticity development of the specimen,and improve the bearing capacity and ductility of the specimens.The cracking load,yield load,and ultimate load of the specimen would be increased remarkably and the reinforcement effect would be significant.Three sets of two specimens were selected for conducting their static test.In elastic stage,the theoretical calculation and software simulation of load vs deflection curve would be consistent with the test result;entering into plastic phase,the theoretical value of tested piece would be much larger than the experimental and simulation value;the test value of the specimen would be consistent with the simulation value,i.e.the simulation result would be credible.