Research on the Anti-cracking Technology for Hogging Moment Regions of Truss-concrete Composite Continous Beam Bridge Deck
The cracking of deck in the negative bending moment zone of the long-span truss-concrete composite girder is studied.Based on the truss-concrete composite girder with main span of 80,120 m,a spatial finite element model was established using midas Civil 2021 software,to analyze the anti-cracking effects of diverse techniques,including optimized construction sequence method,preloading method,prestressing technique and slip-free connecting technique and comprehensive crack resistance technology.It is shown that the optimized construction sequence method can effectively control the tensile stress in the negative bending moment area,but due to the shear concentration effect at the steel truss beam nodes,the tensile stress in the entire bridge deck is at a high level.The preloading method has no contribution to the crack resistance in the negative bending moment zone after the pre-loading force exceeds a certain limit value.The application of prestressing method can directly solve the problem of cracking in the negative bending moment zone,but the secondary internal force genera-ted by prestressing has a significant impact on the stress of the main truss.The slip-free connectors can effectively release the tensile stress in the negative bending moment zone,but it is difficult to re-duce the overall tensile stress level of the bridge deck slab.The comprehensive crack resistance tech-nology optimizes the construction sequence with the using of slip-free connectors,and adopting the method of stage tensioning and prestressing to change the timing of the combination of bridge decks,resulting in good crack resistance performance.
steel truss-concrete composite girdercracking in the hogging moment regionsuplift-re-stricted and slip-free shear studsfinite element analysis
NETL
NSTL
万方数据
