模拟酸雨腐蚀下预应力混凝土梁的抗弯性能研究

Study on flexural behavior of prestressed concrete beams under simulated acid rain corrosion

为了探讨酸雨腐蚀环境对预应力混凝土梁抗弯性能的影响,制作了8根预应力混凝土梁,从混凝土强度等级、预应力度和钢绞线腐蚀率等方面,进行8根预应力混凝土梁的三分点静载试验。试验结果及分析表明,混凝土强度对屈服后试验梁的抗弯性能影响较大,对弹性阶段的刚度影响较小;随着预应力度的增加,试验梁的开裂荷载逐渐增大,进入裂缝阶段后,刚度下降速度逐渐加快;钢绞线腐蚀率越大,试验梁的极限抗弯承载力越低;腐蚀率在一定范围内(>3.22%),随着腐蚀率的增大,预应力混凝土梁试件的开裂弯矩、屈服弯矩和极限弯矩明显降低。根据试验结果,提出了模拟酸雨环境下预应力混凝土梁试件抗弯承载力的计算方法,同时采用ANSYS软件对预应力混凝土梁进行非线性有限元分析,将试验梁的计算值和模拟值与试验值进行比较,均吻合较好。

In order to investigate the influence of acid rain environment on the flexural behavior of prestressed concrete beams,eight prestressed concrete beams were fabricated.They were subjected to three-point bending tests to investigate the concrete strength grade,prestressing ratio and corrosion rate of steel strand.The experimental results and analysis indicate that the strength of concrete has a great influence on the flexural behavior of post-yielding beams,but has little effect on the stiffness of the post-yielding beams;with the increase of prestressing force,the cracking load of the beams gradually increases;after entering into the fracture stage,the rate of stiffness decrease gradually increases;the greater the corrosion rate of steel strand,the lower the ultimate bending capacity of the test beams;within the a certain range( >3.22%),with increasing corrosion rate,the effects of corrosion have a significant impact on the cracking moment,the yield moment and the ultimate moment.Based on the test results,the paper puts forward the formula to predict the flexural capacity of prestressed concrete beams in acid rain corrosion environment;in addition,nonlinear finite element analysis of prestressed concrete beams was conducted in ANSYS software.The experimental results of the test beams are in good agreement with the calculated results and the simulation results.