双层桥面钢桁架连续梁桥静载试验控制指标研究

Study on Control Index of Static Load Test for Double-deck Steel Truss Continuous Beam Bridge

针对现行规范未就双层桥面钢桁架连续梁桥静载试验控制指标做出明确要求,基于实验力学及有限元基本原理建立了双层桥面钢桁架连续梁桥的荷载试验计算模型,利用等效荷载原理分别拟定了以弯矩、轴力作为控制指标下控制截面的静载试验加载方案,比较了关键构件在试验荷载作用下的弯矩、轴力加载效率,明确了双层桥面钢桁架连续梁桥的静载试验的控制指标。研究结果表明:在边、中跨最大正弯矩工况的加载效率满足规范要求的布载方式下,杆件轴力的加载效率最小为1.024,最大为1.259;在边、中跨最大轴力工况的加载效率满足规范要求的布载方式下,杆件弯矩的加载效率最小为0.603,最大为0.992;为确保结构安全,建议双层桥面钢桁架连续梁桥静载试验应以弯矩作为控制指标。该研究成果对于双层桥面钢桁架梁桥的静载试验提供了一定参考。

As the current specifications do not make clear requirements for the static load test control indicators of double-deck steel truss continuous beam bridges,a load test calculation model for double-deck steel truss continuous beam bridges was established based on the experimental mechanics and basic principles of finite element analysis.Using the principle of equivalent load,static load test loading schemes for the controlled cross-section were proposed with bending moment and axial force as control indicators.The bending moment and axial force loading efficiency of key components under the test load were compared,and the control indicators of the static load test of the double-deck steel truss continuous beam bridge were clarified.The research results show that:under the loading mode where the loading efficiency of the maximum positive bending moment conditions of the side and mid-spans meets the requirements of the specification,the minimum loading efficiency of the rod axial force is 1.024 and the maximum is 1.259;under the loading mode where the loading efficiency of the maximum axial force conditions of the side and mid-spans meets the requirements of the specification,the loading efficiency of the bar bending moment is 0.603 at the minimum and 0.992 at the maximum.In order to ensure the structural safety,it is recommended that the static load test of double-deck steel truss continuous beam bridge should use bending moment as the control index.The research results provide a certain reference for the static load test of double-deck steel truss beam bridges.