Key Technologies And Reliability Analysis Of Synchronized Closure Of Long-Span Continuous Rigid Frame Bridge

As a common bridge structure,rigid frame bridge is widely used in the mountainous areas of Southwest China.With the progress of bridge construction technology,higher requirements have been put forward for the construction quality and desirable economic performance of bridges.Closure mode of continuous rigid frame bridges as a key construction process has attracted much attention.Based on the engineering background of a super-long-span continuous rigid frame bridge at Xugu Expressway in Sichuan Province,this paper puts forward a construction method of synchronous closure of continuous rigid frame bridge,and studies the key technology and structural reliability in the process of synchronous closure.The main contents are as follows:1.Considering the conventional closure mode and characteristics of continuous rigid frame bridge,a concretely synchronous closure construction technology of continuous rigid frame bridge is proposed.Based on the actual project,several key technologies in the synchronous closure construction of the continuous rigid frame bridge are studied,such as the weight of closure section,the design and locking of closure rigid skeleton,the construction control of closure pushing and the treatment and maintenance of closure section diseases.2.The refined finite element simulation model of the continuous rigid frame bridge is constructed.The reasonable closure jacking thrust is determined by considering the influence of closure temperature difference and other factors.The internal force of main pier,stress of main girder and alignment of continuous rigid frame bridge under synchronous closure and conventional closure are compared and analyzed.The results show that synchronous closure has little influence on the internal force and alignment of continuous rigid frame bridge.3.Based on the basic theory of existing reliability analysis,a response surface methodology(RSM)is proposed to calculate the reliability of complex bridge structures.The static analysis of the continuous rigid frame bridge is carried out by using finite element software,and the main failure modes are selected.The reliability indexes of the maximum cantilever state and the jacking construction stage of the rigid frame bridge are calculated by using the response surface method reliability calculation program programmed by MATLAB and MIDAS software.The reliability sensitivity of the maximum cantilever state of the continuous rigid frame bridge is analyzed.It is concluded that the variability of the elastic modulus of concrete has the greatest influence on the structural reliability,followed by the variability of the concrete bulk density,and the variability of wind load and hanging basket load has the least influence.