Study On Construction Quality Risk Early-warning Of Superstructure Of Long Span Cable-stayed Bridge

Due to the advantages of high strength,light structure,saving building materials and beautiful shape,the long-span cable-stayed bridge is more and more widely used in highway traffic construction.However,in the actual construction,the stiffness of the superstructure is often reduced with the increase of the span,and the geometric nonlinear effect is more obvious.Coupled with changes in the internal and external environment,making the cable-stayed bridge superstructure construction is facing a series of uncertainty come from physical,model and personnel,and its construction quality has been severely tested.At present,the research on the risk of long-span cable-stayed bridge is mostly about the construction safety risk,and Lack of comprehensive understanding of the construction quality risk warning of the superstructure.Therefore,it is necessary to systematically comb the construction quality risk factors of the superstructure of long span cable-stayed bridge,and carry out quality risk early warning research,in order to achieve scientific and efficient management of its construction quality,to avoid or reduce the risk of the accident.Firstly,this paper studies and reviews the relevant theories of quality risk management and quality risk early-warning,aiming at the particularity of the construction process of the superstructure of the long-span cable-stayed bridge,the source of the quality risk is expounded,revealing the mechanism of risk formation.Secondly,system combing the construction process,combined with the construction site staff comments and suggestions,through the historical literature analysis and so on,respectively from the beam manufacturing,beam assembly,bearing construction,cable construction and deck and ancillary works and other five aspects of construction,carried out the risk identification of the construction quality of the superstructure of the long-span cable-stayed bridge,established a quality risk early warning index system,and set the warning threshold for each indicator.Again,according to the gray relational analysis of the relevant theory,calculate the construction quality risk early warning index weight,based on the BP neural network model,the training indexes deviate from the threshold level,and the construction quality risk early-warning system of superstructure of the long-span cable-stayed bridge was created.On this basis,the use of MATLAB software,design a visual human-computer interaction interface,making the early warning system operability can be significantly improved.Finally,this paper presents the specific application of the early-warning system in the background of the construction quality risk early warning management of the superstructure of the Chongqing Fengdu Yangtze River Bridge.It is proved that the early-warning system has good practicability and feasibility for the construction quality risk warning work of the superstructure of long-span cable-stayed bridge.This paper is completed with the combination of "Chongqing Fengdu Yangtze River Bridge Construction Safety Risk Analysis and Control Research" scientific research project.