腐蚀预应力混凝土梁性能对比试验研究

Comparative Test on Performance of Corrosive Prestressed Concrete Beams

为研究预应力混凝土梁在预应力筋不同腐蚀程度下的力学性能,开展了5片T型模型梁加载破坏试验。采用电化学加速腐蚀方法,对梁体内预应力钢束进行腐蚀,得到腐蚀率为0、5%、8%、10%、12%五种模型试验梁,分别进行加载直至梁体破坏,测试加载过程中梁体挠度、应力、钢绞线及钢筋应力变化,观察梁体的破坏模式,并与有限元仿真分析结果进行对比。试验研究表明:1)腐蚀率为5%时,梁体承载力降低2.9%,挠度降低27.2%,梁体延性下降;2)腐蚀率为8%、10%及12%时,加载过程中钢束出现断丝,承载力分别降低25.7%、34.1%和42.9%,相应挠度分别降低63.4%、69.0%和74.2%,即随着腐蚀率的增加,试验梁延性大大降低,呈现脆性破坏特征。

In order to study the mechanical properties of the prestressed concrete beam under different corrosion levels of prestressed tendons,a destructive test of 5-piece T-type model beams was carried out.The electrochemical accelerated corrosion method was used for corroding the prestressed steel strands in the beams to obtain 5 model test beams with the corrosion rate of 0,5%,8%,10%and 12%respectively.They were loaded until each one was destroyed The deflection,the concrete stress,the stress of the steel strands and the steel bars were tested during the whole process,the failure mode of each beam was observed and compared with the results of the FEM simulation.The experimental results show that:1)When the corrosion rate is 5%,the bearing capacity of the beam decreases by 2.9%,the deflection decreases by 27.2%and the ductility of the beam decreases;2)When the corrosion rate is 8%,10%or 12%,some wires of the tendons break under load,the ultimate bearing capacity decreases by 25.7%,34.1%and 42.9%,respectively.,the corresponding deflections decreased by 63.4%,69.0%and 74.2%,respectively,That is,with the increase of corrosion rate,the ductility of the test beam is greatly reduced,showing brittle failure characteristics.