Steel-concrete Composite Beam Cable-stayed Bridge Main Beam Concrete Panel Shrinkage Effect Analysis

In recent decades,the research on shrinkage prediction model based on the shrinkage mechanism of concrete itself has never stopped.From a macro perspective,lots of relevant achievements have been acquired by analyzing the overall shrinkage effect of steel-concrete composite girder cable-stayed Bridges.But for new concrete,the existing shrinkage prediction model is obviously insufficient to accurately predict the shrinkage strain of new concrete.For space segment model,the interaction of the concrete slab shrinkage effect between the main girder components and the influence of the space internal force and displacement of the composite beam can not be fully reflected in the full bridge plane model.Therefore,the focus of this paper are as follows,accurately choose the shrinkage prediction model of concrete;analyze the calculation principle of concrete shrinkage in steel-concrete composite beam;accurately establish the plane model and space segment model of the whole bridge.Several aspects are studied and analyzed in this paper to analyze the shrinkage effect of concrete slab of steel-composite girder cable-stayed bridge.(1)The calculation method of geometric nonlinear problem of long-span cable-stayed bridge in the self-made finite element program BDCMS and numerical simulation of convert the shrinkage strain of concrete bridge deck into equivalent joint load by means of the initial strain method is described in detail.(2)The shrinkage prediction model of C60 concrete bridge deck and the shrinkage prediction model of cast-in-situ mixed soil were determined by analyzing several classical models of concrete shrinkage prediction and the shrinkage test of superperformance concrete.(3)Taking the Chibi Yangtze River Highway Bridge—the steel-composite cable-stayed bridge with the largest span under construction in the world as engineering background,the plane model of the whole bridge is established by using bridge finite element software BDCMS.The stress(internal force)redistribution law and structural displacement law of steel-concrete composite girder under the influence of shrinkage effect are obtained.(4)The spatial segment model of the standard girder section of Chibi Yangtze River Highway Bridge is established by ABAQUS.The concrete slab of the main girder is divided into four construction technologies—precast bridge slab+new concrete cast-in-place,precast bridge slab+ordinary concrete cast-in-place,integral cast-in-place and integral precast.According to the calculation results,the influence of the shrinkage effect of concrete slab on the structural displacement of the steel girder and the concrete slab and the redistribution law of stress(internal force)are summarized.The shrinkage effect of main girder concrete slab on four different construction techniques of concrete slab are compared and analyzed in this paper and relevent suggestions are given for the construction of main girder concrete slab.