Study On Construction Risk Managment Of Large Bridges Engineering

Proceeding from the actual fact of large bridge construction, combined with the existing risk management theories, on basis of establishing construction risk management process, construction risk management is systematically studied from the aspects of construction risk factors identification、risk estimation and evaluation、 risk response, and etc. The new method of construction risk management of large bridges is presented from the view point of practicability and operability. In this thesis, the main research results are as follows:(1) Combined with the characteristics of bridge construction and the existing definition of risk, the concept of construction risk for bridge is presented. Then based on bird causal chain theory, construction risk-causing model is established and thus provide the theoretical foundation for the study on construction risk management of bridges.(2) Construction risk identification is studied by applying WBS-RBS method. BCICS (Bridge Construction Information Classification System) is put forward and a unified WBS frame for bridge construction stage is built. Then through classifying construction risks by source, RBS is established.Thus, a RBM (Risk Breakdown Matrix) is generated.Finally the nominal group technology (NGT) is applied to judge the elements of RBM and identify risks. This modular method for risk analysis makes risk management personnel goal-oriented. Furthermore, the proposed BCICS is helpful for communication and computer storage of risk information.(3) The Bayesian network is introduced into construction risk probability estimation, and then a risk probability estimation model based on Bayesian network is proposed. The model not only can calculate probability of risk events and determine the risk probability level but also can find out key risk factors, and thus provide the scientific basis for risk response.(4) On the basis of classifying construction risk loss of bridges and giving hierarchical description for each kind of loss by using qualitative loss estimation method, The comprehensive estimation model is put forward to make a total description for construction risk loss.(5) Combined with the proposed construction risk probability and loss estimation model, risk matrix evaluation method based on ALARP is presented to assess the construction risk of bridges.(6) Considering complexity and uncertainty of the risk and fuzziness of people cognition and on the basis of traditional AHP, The group AHP based on interval number judgment matrices is established for Priority sort of the risk response measures.