体外预应力节段预制拼装混凝土梁疲劳试验研究

Fatigue Test of Prefabricated Concrete Beams with External Prestressing Segments

为研究体外预应力节段预制拼装混凝土梁的抗疲劳性能,设计制作了1∶3缩尺模型,进行设计荷载下的疲劳模型试验研究。综合对比国内外多种疲劳荷载计算方法,确定试验疲劳等效荷载;在此基础上,进行了体外预应力节段预制拼装混凝土梁的抗疲劳理论分析和200万次疲劳加载试验。理论分析结果表明,节段预制拼装梁包含的混凝土和体外预应力构件抗疲劳能力具有较大余量,不控制结构的耐久性;试验结果表明,模型在200万次疲劳加载后,各部位均未发现疲劳裂纹,模型的力学特性未随循环次数的增加而发生明显改变,验证了结构设计的合理性和安全性。

In order to study the fatigue resistance of prefabricated concrete beams with external prestressing segments,a 1∶3 scale model was designed and manufactured,and the fatigue model test under the design load was carried out.The equivalent fatigue load of the test was determined by comparing various fatigue load calculation methods at home and abroad;On this basis,the theoretical analysis of fatigue resistance and 2 million fatigue loading tests were carried out.The theoretical analysis results show that the fatigue resistance of the concrete and external prestressed components in the segmental prefabricated beams has a large margin and does not control the durability of the structure.The test results show that no fatigue crack is found in every part of the model after 2 million times of fatigue loading,and the mechanical properties of the model do not change significantly with the increase of the number of cycles,which verifies the rationality and safety of the structural design.