Research And Application Of Mechanical Properties Of Waveform Steel Web Bridges With Unequal Span Continuous Rigid Structure

Compared with concrete bridges,waveform steel web bridges have the advantages of improving web stressing performance and reducing diseases,so this type of bridge has been rapidly developed in China in recent years.In this paper,the first link of the north approach bridge of Nanjing Xianxin Road river crossing is used as the background of the study.The structure of this bridge is a five-span unequal span continuous rigid waveform steel web-concrete combination beam.The paper uses finite element software for simulation analysis and investigates the mechanical properties of the bridge during the construction process.The main work and research results are as follows:(1)Equivalent analysis of waveform steel web-concrete composite beam.An equivalent method of replacing waveform steel webs with concrete webs is proposed using theoretical derivation,and a solid element model of the I-beam waveform steel web-concrete composite girder section is established and compared with the equivalent converted rod system element model to verify the feasibility and accuracy of the equivalent replacement.The equivalent replacement models of box section for simply supported girder bridges and continuous girder bridges were further investigated.The results show that the equivalent replacement method simplifies the calculation of waveform steel web bridges and improves the research and calculation efficiency.(2)Static characteristics analysis and comparison.Finite element software was used to establish the full bridge model,and computational analysis was performed on the bridge at the maximum cantilever stage and after completion to study its deformation and force state.The prearch and elevation of the standing form in the construction stage were calculated,and the theoretical values were compared with the monitored values in construction to verify the accuracy of the equivalent replacement model.The alignment of the main girders after completion of the bridge was further compared and analyzed to verify that the results of the alignment monitoring met the code requirements.(3)Sensitivity analysis.Five parameters with large variability in the bridge construction process were selected,and the possible variation of each parameter was studied,and the sensitivity of the structural response to each parameter was analyzed by finite element calculation,and the parameters were ranked,and the most sensitive parameter to the structural response was the main girder capacity,then the internal prestress,external prestress,pipe friction coefficient,and pipe deviation coefficient in order.The main beam capacity,internal prestress and external prestress are sensitive parameters,and the pipe friction coefficient and pipe deviation coefficient are non-sensitive parameters.(4)Study of the girder solution.For the construction process of this bridge,different girder girder girder co-location schemes were proposed,and the influence of counterweight in bridge girder co-location construction was analyzed.The influence of different sizes of the counterweight water tank on the concrete top slab of the box girder was simulated,and a suitable water tank was selected for counterweighting.The influence of the counterweight loading position on the overall alignment of the completed bridge when considering the cross slope was analyzed,and the influence law of four different girder girder girder closure schemes on the mechanical properties of the completed bridge was studied.