Analysis Of Early Cracks Cause In Width Girder Cable-stayed Bridge With Single Cable Plane

For the past few years，With the development of economy and the expanding ofcity construction, bridge span is constantly increasing, bridge forms have becomevaried. Ordinary bridge has been unable to meet the aesthetic requirements of thepeople and a variety of new large-span bridges are applied to the construction of urbanbridges. Width girder cable-stayed bridge with single cable plane as a new type ofbridge, meet the need of the urban construction in beauty, and meet the requirementsof increasing urban traffic,and also meets the need of spanning capacity.However thedesign theory is not perfect,and the shortcomings of the construction quality and variousaspects of factors,make it easy to width girder cable-stayed bridge with single cableplane to crack in the construction process.Cracks appeared on the stress of the bridgestructure and the use is quite bad,so,the analysis of early cracks cause in width girdercable-stayed bridge with single cable plane for design and construction is necessary.This paper takes chongqing double tablet in the jialing river bridge (mainspan330meters, the beam width32.5meters, width girder cable-stayed bridge with single cableplane) as the engineering background.The bridge in zero block the second pouring,thebox girder of the base plate,flange plate and diaphragm plate produced a large numberof cracks,the bad effect have not only on it’s beauty but also on bridge construction andlater operation. So this article aimed at analyze phenomenon of the bridge inconstruction at zero block bottom, flange plate, diaphragm plate crack.This article first show the characteristics of width girder cable-stayed bridge withsingle cable plane,a introduce about the research status of the cracks on bridge at inlandand outland;and then describe the cracks distribution of chongqing jialing river bridge’szero block crack,and analyze the causes of bridge cracks for the shallow; Finallyseparately calculate the effect under the action of the gravity and cable force, the effectof prestressed and hanging basket, concrete lateral contraction effect on the influence ofthe main girder, the influence of the temperature effect on the main girder.In the calculation of the action of gravity and cable force, through the analyzationof various affecting factors’calculation then conducted the real distribution of bridgecrack, summed up the focus area cracks ratio, so as to know the causes of cracks oneach part as well as a major cause of cracking. From the consequence of the analysis of various factors, the temperature effect is a major cause of concrete cracking, the heatgenerated by the temperature in the heat of hydration process rise so that thetemperature of the concrete followed, concrete temperature rise to a certain degree, inthat time heat production and concrete hydration heat reached to a balance, and thenbegan to cool, cool cause shrinkage of concrete, therefore, the initial set of concretecracks appeared. Secondly shrinkage is another important cause of concrete cracking,old and new concrete pouring time apart is too long, make the new pouring concrete andold concrete’s shrinkage rate gap is too large, which constraints the new deformation ofthe new concrete so the cracks show up, and with the time goes by, the crack is still indevelopment.