Research On Bending Static And Fatigue Performance Of Lightweight STC-Steel Composite Bridge Deck

In order to alleviate or even cure the fatigue cracking of traditional orthotropic steel bridge deck and the easily damaged pavement,and to improve the economy and construction convenience of closely reinforced STC-steel composite deck at this stage,taking a steel box girder overpass in Foshan as the engineering background,this paper designed and made four full-scale strip models of STC-steel orthotropic composite bridge deck with two different reinforcement ratios,and comprehensively probes into the cross-section reinforcement ratio of STC layer.According to the influence of main design parameters such as steel fiber volume content and steel deck stud spacing on the bending,tensile,static and fatigue properties of composite bridge deck STC layer,a lightweight STC-steel orthotropic composite bridge deck structure was proposed,which meets the stress requirements of engineering structure and is more economical.The main research contents are as follows:(1)The full-scale strip model of the STC-steel orthotropic composite bridge deck under different reinforcement ratios was carried out in the bending static test.Taking a steel box girder overpass in Foshan as the engineering background,a full-scale strip model of the STC-steel orthotropic composite bridge deck with two different reinforcement ratios was designed to resist the negative bending static load failure test,revealing the high fiber content The distribution law of the section reinforcement ratio on the cracking strain and crack propagation.The influence of the section reinforcement ratio of the STC layer on the deflection,ultimate bearing capacity and failure mode of the composite bridge slab is studied.The nominal cracking stress of STC layer was calculated based on the linear elastic and flat section assumptions.(2)The finite element model of STC-steel orthotropic composite bridge deck was established considering material nonlinearity and geometric nonlinearity.The nonlinear simulation of the whole process of static failure test was carried out by using ABAQUS finite element software,and the negative bending resistance of composite bridge deck under various design parameters was explored.The influence rules of interface bonding mode,STC layer thickness and section reinforcement ratio of STC-steel were mainly analyzed and compared,and the feasibility of lightweight STC-steel composite bridge deck was verified.(3)The full-scale strip model bending fatigue test of STC-steel orthotropic composite bridge deck slab under different parameter combinations was carried out.This paper mainly discussed the effects of orthotropic steel bridge deck stud spacing,STC layer reinforcement ratio and steel fiber volume content on the bending tensile fatigue cracking life,fatigue crack failure characteristics and maximum crack width after fatigue cracking of composite bridge deck STC layer.The comprehensive optimal design parameters of lightweight STC steel composite bridge deck structure with better fatigue performance and economy were obtained.