Reliability Of The Long-span Continuous Rigid Frame Bridge With High-Piers In Construction Stage

The construction of large and complex bridge projects generally has the characteristics of large-scale construction,long construction cycles,complex internal structures,and extensive external connections,these characteristics determine that many uncertain factors must exist during the construction phase of the project.These uncertain factors will affect the reliability of the bridge project to different degrees separately in construction period.It will lead to safety or quality accidents if some adverse factors with immense impacts are not properly considered or appropriately handled.In-depth research on the reliability of the bridge project during the construction period to ensure that the bridge structure has sufficient safety reserve capacity during the construction phase.Improving the construction quality is of great significance to the construction of comprehensive transportation system,the promotion of national economic development and the creation of a harmonious society.This paper is based on the real construction project of Hong Nong Jian bridge,which is in the newly southward-moving construction project from the part of 310 national road from Western Sanmenxia city to the boundary of Henan and Shaanxi province.Besides on the ground of in-depth study of the current industry specifications and relevant literatures,the reliability of the long-span continuous rigid frame bridge with high piers in construction stage is studied,and achieved the following major results:(1)The paper closely combined with the characteristics of long-span continuous rigid frame bridge.,comprehensively and systematically analyses the influential factors of the long-span continuous rigid frame bridge with high piers in terms of structural reliability.The factors affecting the resistance during construction are categorized into three aspects: material performance,structure geometry and calculation mode.(2)Based on the design scheme and construction process of Hong Nong Jian Bridge,the stress characteristics and failure modes of each main structure of continuous rigid frame bridge during construction are analyzed,the models of resistance and action effect of Pile Foundation,pier and main girder under the most unfavorable working conditions are established,which lays a foundation for the reliability analysis of bridge during construction.(3)The Hong Nong Jian bridge(long-span continuous rigid frame bridge with high piers)is selected as the research object.Based on the structural resistance and the action effect model in each construction stage,the reliability function of the pile foundation,pier and girder of the bridge is established respectively.The improved JC method is used to calculate the reliable indexes for each stage of the bridge construction period.,the quantitative evaluation of Bridge Construction Safety in construction period is realized.The evaluation result of this example shows that the main structure has enough safety reserve in every phase of construction.(4)Based on the theory of structural reliability,this paper analyzes the sensitivity of the factors affecting the structural reliability in different construction stages and determines the key factors affecting the construction safety and construction quality in different construction stages.In the light of the results of sensitivity analysis,some suggestions are put forward to improve the construction quality and safety level in each separate construction stage.