Experimental research of mechanical properties of integral joints of continuous steel truss girder in pushing sliding process

In this paper, the stress distributions of the key joints in the most unfavourable case during construction were analysed for the highway-railway combined bridge across the Yellow river between Shijiazhuang and Jinan. The pushing sliding technology was firstly used for the construction of the huge continuous steel truss bridge with rigid suspension cable stiffening chords in China. Firstly, the typical joints subjected to the maximum reactive force during the bridge construction were selected to conduct the mechanical testing on site. The stress sensors were arranged in some positions of the joints, at which the finite element analysis had predicted larger stresses. Then, the stress values were measured by the resistance strain gauge, and the test results were compared with the finite element analysis results. Due to the deviation between the actual lifting position and the planned lifting position, as well as the synchronization issue of the three-truss lifting, the local stress level of some joints is relatively high in a short period. In the most unfavourable case, the maximum measured stress reachs 329 MPa, which is close to the yield strength of 330 MPa. According to the test results, under the most unfavourable condition, the stress of the key joints can meet the structural strength requirement. © 2020, Editorial Office of Journal of Building Structures. All right reserved.