Researsh On Construction Period Risk Early Warning System Of Continuous Girder Bridges

In recent years,with the rapid development of road transportation,the position of bridges in highway transportation becames more and more important. But frequent safety accidents result in great loss of national property and led to a large number of personnel casualties. Therfore, to establish an early-warning mechanism on large bridge under construction is important part to ensure the safety of construction, and to avoid the accident.This paper firstly analyses the causes of 30 bridge accidents during the construction period in recent years. Combined with the construction technology of long span bridge, it then summarizes the reasons of the accidents, which lays the foundation of building the early-warning systems and establishing the evaluation system..Then, according to the analysis of early warning system on the causes of the accidents and early projects and combining with the researches on the early warning system of scholars’ early theories, it discusses the common features of the early warning system between long span bridge and its similar projects such as of coal mine accidents and earthquakes, and finds out long span bridge’s unique features.Based on ISO31000 standard risk management theory, it constructs the frame of early warning system of long span bridges, consisting of management subsystem and operation system. It differs with the existing early warning system in adding the organization system and improvement system, and on the basis it studies the operation mechanism of the early warning system of long span bridge.The other similar warning system often ignores the organization theory, conversely, this thesis, in accordance with organization theory and early warning system theory, establishes the early warming operation structure of long span bridge, identifies the personnel and their responsibilities, and describes its process of work.Finally, from the relating literatures and analysis of causes of the frequently-happened accidents that discussed before, it determines the evaluation index, constructs the evaluation model and researches the emergency feedback system. It focuses on the case of Suqian Culture Bridge, and based on its analysis, it puts forward some risk control suggestions.This paper solves the problems in integrity and logic of other early warning system projects, and it integrates the early warning system of long span bridges into a complete, persistent organic whole.