Analysis And Prevention Methods For Construction Cracks Of Continuous Rigid Frame Bridge In Plateau-cold Mountain Region

Prestressed concrete continuous rigid frame bridge has been widely used in engineering practice because of its rational force and good driving comfort.Continuous rigid frame bridge belongs to the multi direction prestressed statically indeterminate structure,and the construction process has a great influence to the finished bridge,so special attention should be paid to construction control.However,the study found that quantities of continuous rigid frame bridge had emerged cracks during the construction stage,and the special environment of the plateau-cold mountain region could increase the number and expansion of cracks during the construction period.Cracks during the construction period will affect the progress of the bridge construction,and reduce the durability and bearing capacity of the bridge,even cause the safety accidents,it has been a problem that needed to be solved by engineers immediately.In this context,the causes of cracks of continuous rigid frame bridge in the plateau-cold mountain region during the construction period area were analyzed in this paper,and the corresponding improvement measures had been put forward.The main contents and conclusions of this paper include:(1)Aiming at the cracks of continuous rigid frame bridges in plateau-cold mountain region during the construction period,after extensive research,the types and mechanism of cracks of continuous rigid frame bridge during the construction period wre analyzed,and the related factors of cracks in the plateau-cold mountain region of continuous rigid frame bridges during the construction period were analyzed.(2)Yunnan Old TuanPo No.2 Bridge was simulated by using Midas/Civil and ABAQUS finite element softwares,and the stress of the structure under temperature load,loss of prestress,partial deteriorated strength of concrete and low loading age of concrete were calculated,and sensitivity analysis on influencing factors of cracks of continuous rigid frame bridge during the construction period is carried out.The results show that the change of the bridge stress caused by adverse factors leads to tensile stress exceeding the tensile strength of concrete,which is the root cause of cracks of continuous rigid frame bridge during the construction period.The influence caused by the single adverse factor on the stress of the bridge is little,cracks are produced by the coupling interaction of multi factors,and influence of temperature load and prestress loss on cracks is larger,but the influence of partial deteriorated strength of concrete andlow loading age of concrete is little.(3)According to the related factors of cracks of continuous rigid frame bridges in plateau-cold mountain region during the construction period,started from three aspects such as design,construction and human error of the continuous rigid frame bridge,the corresponding improvement measures has been put forward to improve the quality of the construction of the continuous rigid frame bridge in the plateau-cold mountain region.The causes of cracks of the continuous rigid frame bridge in the plateau-cold mountain region during the construction period were analyzed in this paper,and corresponding improvement measures has been put forward,which can provide the technical support for the design and construction of continuous rigid frame bridge in high and cold environment,and avoid catastrophic accidents of bridge structures due to the influence of cracks during the construction period,and promoted the progress of construction technology of the continuous rigid frame bridge and development of transportation in the plateau-cold mountain region.