双向荷载作用下 FRP 复合材料横担体系受力性能试验研究

摘要

为了解 FRP 复合材料横担在双向挂线荷载作用下的力学性能，本文对其进行了模拟双向荷载作用下的足尺试验研究，观察了复合横担试验现象，分析了复合横担整体受力与位移关系曲线，并对横担梁和拉索的 FRP 复合材料及钢套管的应变分布规律进行了深入分析。研究结果表明：复合横担体系在设计荷载作用下整体变形明显，横担梁中部截面外鼓变形明显，拉索侧向位移较大；复合材料层间发生轻微撕裂现象，复合材料与钢套管之间连接可靠，未发生粘结滑移破坏；荷载与位移之间基本呈线性变化，曲线没有出现明显的突变或拐点，复合横担基本处于弹性工作状态，表现出较好的受力性能；横担梁复合材料应变大于其钢套管应变，横担梁中部截面应变最大；拉索复合材料应变随荷载的增大而迅速增大，且远大于其钢套管的应变；拉索受力大于横担梁，需对拉索采取一定的增强措施，以保证横担体系的整体受力要求。复合横担试验荷载达到了工程设计要求。%In order to understand the mechanical properties of FRP composite cross arm under bi-directional hanged line load,the full scale experimental study of the FRP composite cross arm un-der two-way loads is performed.The experiment phenomenon of the composite cross arm is ob-served in detail.The resultant force-displacement curves and the strain distribution laws of com-posite material and steel casing in the cross arm beam and inhaul cables are also analyzed in depth.The results show that the overall deformation of cross arm system under the designed loading is very obvious.The middle cross-section’s deformation of the cross arm beam is larger than other parts in this test.Meanwhile,the lateral displacement of inhaul cables is also obvious. A slight avulsion phenomenon between the FRP material layers has been observed.And the bond-slip failure has not happened between the composite materials and the steel casing,which reveals that the connection area is reliable.The linear variation is obtained in the load and dis-placement curve and it does not appear to have obvious mutation or an inclined point in the curve, which shows that the composite cross arm is in elastic working state and shows a good mechanical performance under two-way loads.The strain values of composite materials is larger than that in the steel casing in the cross arm beam and the middle cross-section’s strain of the cross arm beam is the largest in all the strain values.In addition,the strain values of composite materials in the inhaul cables increase with an increase in magnitude of test loads,which is larger than the steel casting’strain.According to the test,the load that the inhaul cable suffered is larger than that of the cross arm beam.Therefore,in order to ensure the bearing capacity of cross arm system, some strengthening measures should be adopted in the transmission tower.The test load of cross arm has met the requirements of engineering design and the research result has a great signifi-cance for the application of composite cross arm.