Research On Mechanical Behavior Of Upper Longitudinal Rib Steel And Concrete Composite Bridge Deck

The RC (Reinforced Concrete) composite bridge deck with upper longitudinal rib is asuperior type of structure than that of the lightweight concrete composite pavement structureunder the rigid layer and traditional orthotropic steel bridge panel which has greatly improvedthe fatigue problems of orthotropic steel bridge panel vertical and horizontal rib at the jointsand the early diseases of steel bridge deck pavement layer. Upper longitudinal rib RCcomposite bridge deck is a new deck structure system that places the longitudinal rib at theupper layer. As the PBL shear connectors and steel and concrete formated composite structure,the structural behavior is different from ordinary orthotropic bridge deck pavement and thedesign control index is different, either. In this paper, the interface mechanical property ofsteel and concrete was studied by shear launch and fatigue test,and the failure mode andbearing capacity calculation method was obtained.This paper also verfied whether the newcombination bridge panel could meet the need of practical engineering based on the finiteelement method, then provided the corresponding theoretical support for the application ofthis new structure. The main research results and conclusions are as follows:(1) The newcomposite bridge deck structure form and its design control index were raised by applying theprinciples of longitudinal stiffness equivalent which combined with the characteristics of steelcomposite structure: maximum tensile stress of concrete layer; interlaminar shear stressbetween concrete and steel; the local deformation of bridge panel.(2) The PBL connector launch and fatigue experiments suggested that the concretedamage is the main failure mode; the structural ultimate bearing capacity and ductility withthe reinforcement inside are greatly improved; shear slip stiffness only associated with theholes inside concrete area. The resistance to shear slip stiffness in the elastic stage was alsoobtained through the experimental data.(3) This paper also established the "shell-entity"3D finite element model of the upperlongitudinal rib RC composite bridge deck, then found out the most unfavorable loadpositions. The results showed that the transverse load of the composite structure parametersis almost of no effect, and the longitudinal load has significant effects on structure due to theexistence of the small cross rib. Maximum longitudinal tensile stress of concrete layer is greater than the transverse tensile stress, which was set at the first control indicators. The localeffect of composite structural loads is not obvious, and the mechanical performance issuperior to the traditional structure of bridge deck pavement.(4) The influences of the control indicators to the RC composite structure were analyzedunder the most unfaovorable load.Analysis results show that the girder web plate spacing, thethickness of concrete and the steel panel thickness have the most significance impact on thelongitudinal maximum tensile stress of concrete, followed by the height and form of the smallacross, while the size of the across space and the space of the upper longitudinal rib have littleeffects on stress of concrete.(5) The reasonable proposals for parameters selection of large span and middle span bridgedeck structure is presented based on the parameters analysis.