| Since the reform and opening up,a number of cable-stayed bridges have been built in our country.But the cables produced early has a low material strength as well as poor corrosion resistance,and the quality of its construction and maintenance operations often can not meet the design requirements.What is more,the current vehicle overload situation is serious,resulting in a great fatigue stress amplitude and severe high stress corrosion condition of cable,all of which lead to a shorter service life of the stay cable compared with that of design.After 2000,several cable-stayed bridges have collapsed in our country,which caused heavy economic losses and adverse social impact.At present,a large number of cable stayed bridges exits the hidden security risks,and many of them enter into the cable replacement period.Because of the lack of technical standard of cable replacement of cable stayed bridges,the design and construction of it exit great blindness.Therefore,it owns an important engineering significance and theoretical research value of the systematic research on the performance evaluation and cable replacement of cable stayed bridge.The thesis based on a concrete cable-stayed bridge,as the background,which operating for 25 years.To study the system performance evaluation method,the control process and method in construction monitoring systematically,and the main results are as follows:1.Base on the analysis of the cable force,the safety performance evaluation and the research status of corrosion.This thesis comes up with a method of the cable system performance comprehensive evaluation,which for whether to replace the cables.Offered to suspension cable force evaluation value for analyzing stay-cables full life cycle phase,and then mainly analyze the third stage,combining with the relevant corrosion research and three cable discriminant conditions,according to the testing data of liuzhuang bridge in service to evaluate the cable system performance of liuzhuang bridge,and according to the evaluation results,suggestion of whether replace the cable or not is given.2.According to the characteristics of the liuzhuang bridge reconstruction project,this thesis puts forward a kind of construction monitoring and control method for effective protecting the The original structure of the old bridge.Simulation analysiswas carried out on the construction process,and detailed analysis of the construction monitoring and control method.Through the analysis of the data,and then which validate that the presented construction monitoring and control method is effective and reasonable.3.According to the characteristic of reconstruction project of liuzhuang bridge.Comparative analysis was made for the differences and similarities of bridge cable dismantling and new bridge construction in the process of construction monitoring.To analyze the constructional error influence and temperature sensitivity of new liuzhuang bridge.Build new liuzhuang space model of cable-stayed bridge,using software Midas/civil,to simulate the process of construction.With the cable force and bridge deck elevation as the master project,through the analysis of the results of construction monitoring,which show that cable force,geometric deformation and stress an so on of new cable-stayed bridge are all reach the goal of construction monitoring. |
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