基于悬吊系统的钢-混凝土组合桥面系试验

TEST ON THE STEEL-CONCRETE COMPOSITE GIRDER BY USING SUSPENSION SYSTEM

新型抗拔不抗剪T型连接件(T型连接件)能有效改善组合梁负弯矩区混凝土的抗裂性能。为研究悬索桥桥面系受力状态,同时探究T型连接件对组合桥面系力学性能的影响,该文开展了钢-混凝土组合桥面系的悬吊试验研究,并建立了ANSYS有限元模型对试验结果展开分析。构件采用工字型截面,在构件北侧南侧分别设置T型连接件和栓钉。试验中采用悬吊装置将构件吊起,加载方案包括弹性工况、扭转工况及极限工况加载。研究结果表明T型连接件能有效降低混凝土拉应力。在正常使用阶段T型连接件对桥面系刚度影响较小,在屈服荷载后才会因显著的界面滑移导致刚度下降;此外T型连接件也会一定程度降低桥面系扭转刚度。T型连接件的使用会增大钢结构压应力,设计时需注意钢结构的防屈曲设计。为充分释放钢-混凝土界面剪力,T型连接件在设计时塑料泡棉的厚度应满足正常使用阶段界面最大滑移量的要求。此外,试验结果也体现出悬索桥桥面系与连续梁受力状态的差异。该文研究成果能为T型连接件的后续理论分析及工程应用提供支撑,基于悬吊系统的试验方法可为悬索桥试验研究提供借鉴。

A new kind of uplift-restricted and slip-permitted T-shape(URSP-T)connector was introduced to decrease the tensile stress of the concrete slab in composite girders subjected to hogging moment.To investigate the performance of a suspension bridge and to study the influence of URSP-T connectors on a composite girder,a three-span composite girder was tested by using a suspension system,and a finite element model was established by ANSYS to analyze test results.The specimen adopted an I-shaped form,and URSP-T connectors were installed at the north side of a specimen to compare with the studs installed at the south side.In the test,the specimen was lifted by the suspension system,and the loading scheme included elastic working conditions,torsional working condition and ultimate working condition.The results showed that URSP-T connectors could decrease the tensile stress of concrete slab effectively.The bending stiffness of a bridge girder was little influenced by URSP-T connectors under normal use stage,but significant interface slip occurred after yield load and the bending stiffness decreased correspondingly.Besides,the torsional stiffness of a bridge girder was also reduced by URSP-T connectors to some extent.The use of URSP-T connectors would increase the compressive stress of a steel girder,and attention should be paid to the buckling behavior of a steel girder in design.To fully release the shear force at a steel-concrete interface,the thickness of foamed plastics should meet the requirement of the maximum interface slippage under normal use stage.The test results also revealed the differences between the supporting system of a suspension bridge and that of a continuous beam.This study can support the subsequent analysis and engineering application of URSP-T connectors,and the test method can provide a reference for the experimental study of suspension bridges.