Experimental Study On Transverse Distribution Coefficient Of Hollow Slab Bridge Under Different Widening Connection

In order to study the precast hollow slab bridge widening new and old the longitudinal plate girder,it is tied with Rigid,a semi rigid joint and hinged connection mode.The static stress distribution,deflection and transverse load distribution of the bridge structure under different longitudinal joint connections are analyzed.The method of widening and strengthening the hollow slab old bridge by using the new material such as sticking steel plate and quick setting concrete is explored.Experimental model was set up at key structural laboratory of Chongqing Jiaotong University.The model is divided into four types: old bridge,flexible(I type seam),semi rigid(II type seam)and rigid(III type seam).Loading the designed load condition,The deflections and strains at the 1/4,1/2 and 3/4 of each hollow slab beam are obtained in four cases;Numerical analysis of the old and new bridges using MIDAS,Numerical analysis of the four cases,Modeling of each situation is critical,Especially for the old and new bridge joints(longitudinal seam)simulation,The equivalent simulation should be carried out according to the experimental model;In the finite element simulation,The joint is connected by the beam element,The I type joints are mainly directly equivalent to the axial stiffness and flexural rigidity of the aggregate concrete,which are given to the beam element,The II and III joints are the steelconcrete composite section with polymer concrete and steel plate,By the cross section conversion principle,Convert steel sections into concrete sections,Calculate the EA and EI of the cross section by beam element;Loading on the basis of the model is loaded with the same experimental conditions,The deflections and strains at each 1/4,1/2 and3/4 of each hollow slab beam are obtained in four cases.Through the analysis of the experimental data,it is concluded that the vertical structure of the hollow plate beam bridge adopts a reasonable longitudinal seam connection mode,and the single side is widened,Not only in geometry space,but also directly increase the width of bridge deck roadway and enhance traffic capacity,But also the lateral load distribution coefficient of the hollow slab on the side of the main bridge near the widening longitudinal joint can be obviously reduced,Improving lateral bending torsion rigidity of old bridge;Approach the hollow plate that widens the longitudinal joint,The decrease of load transverse distribution coefficient is more obvious;The longitudinal joint stiffness is greater,The lateral load distribution coefficient of the hollow slab of the old bridge is lower,and the overall is more obvious.This experiment provides guidance for the design and construction of the longitudinal joint connection of old bridges;It provides reference for new material and new technology used in longitudinal seam joint widening of old bridge.