Analysis and research on the causes of construction cracks in webs of long-span continuous rigid frame bridges
Oblique cracks occurred in the web of box girder during cantilever casting construction of a continuous rigid frame bridge in Guangxi.In order to analyze the causes of these cracks and avoid such construction defects,through field in-depth investigation,the corre-sponding theoretical analysis of the causes of cracks was carried out,and the main influencing factors were simulated by ABAQUS finite element software,so as to reveal the causes of inclined cracks.Based on the calculation results,a series of improvement measures were pro-posed.The results show that when the vertical tensile stress of the web of the box girder exceeds the design value of the tensile strength of the original concrete(2.51 MPa),the web of the box girder will crack.In order to prevent web cracking in the process of vertical prestress-ing,it is suggested that the first tension should exceed 60%of the design load,and the vertical prestressing should be fully tensioned before the construction of the next section to prevent the loss of prestressing.The elastic modulus of concrete also has a great influence on the ten-sile of the web of box girder.In order to reduce the risk of cracking,it is necessary to ensure that the tensile age of concrete is above 7 days.
bridge engineeringcontinuous rigid frameoblique crackfinite element calculationcause analysis
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