服役预应力混凝土电杆极限承载力试验研究

An experimental study on the ultimate bending capacity of in-service prestress concrete pole

为了准确评估服役30年的预应力混凝土电杆的安全性能,对现场随机抽取的3根电杆分别进行了抗弯加载试验,研究此种电杆的受力性能及破坏机理,并揭示其破坏形态,获取开裂荷载、正常使用状态极限荷载、承载能力状态极限荷载等重要试验数据,且基于试验实测数据,做出受力全过程的的荷载-裂缝宽度以及弯矩-挠度等一系列曲线。试验结果表明:试件的破坏形态属于"少筋梁"的破坏形式,基于正常使用极限状态设计法,电杆距离倒塌破坏平均具有1.2的安全富余系数。

In order to assess accurately the safety performance of prestress concrete in service for 30 years, bending tests on 3 samples extracted randomly were carried out. The mechanical behavior and failure mechanism of the samples were studied, and the failure modes are revealed. Important experimental data including the cracking load, the serviceability limited state load, the ultimate limit state load were obtained. Furthermore, based on the test data, the curves of load-crack width and moment-deflection of the entire loading process were obtained. The results show that the failure modes of specimens are similar to those of ＂less-reinforced＂ beams, moreover, based on the serviceability limit state design, security surplus factor is 1.2 before collapse.