The Research On Construction Control And Security Risk Assessment Of Cantilever Arching Cast-in-situ Arch Bridge

The arch cantilever construction Method cast of reinforced concrete arch bridge is widely used when there is cliffy canyon for its mature technics and less restricted by the landform. This thesis is based on the research object of bridge mijiashan Guizhou province,and which is about to do some calculation and monitoring work of construction control for the key construction phase of Cast Cantilever bridge arch.Combined with the risk research actualities of our country,the thesis did some researches of risk analysis theory and method from the aspects of bridge construction risk distinguish and risk evaluation,after which the author take construction phase risk evaluations of mijiashan bridge.The highlight of the thesis are as followed:(1) The construction technics flow of the bridge are expatiated in this thesis according to the construction character of the Cast Cantilever bridge arch.The thesis computes the value of the initial tension of the halyard and its fluctuation value by elasticity-rigidity bracing method.and also the construction stability of the arch shelf is calculated in the paper.(2) The author established a model which contains steel arch shelf and the whole main arch ring by the finite analysis software MIDAS/Civil,and based on which the author did researches on combined stress effect of the arch ring and arch shelf and it showed that the arch ring can bear 45% of self load and the arch shelf can bear the rest 55% during the arch pouring.According to which mentioned in the foregoing paragraphs or chapters we can decrease the use of steel arch shelf thus to decrease the cost of construction.(3)The paper detailed explained the construction monitoring results of the main construction phase for the mijiashan bridge.also the author monitored the linear and stress of the tension of halyard,the main arch ring and the steel arch shelf.The actual measurement data shows that the actual measurement value and the theoretical linear value are small,and the stress distribution is reasonable under the procedure of arch shelf assembly,the prepress of steel arch shelf and the main arch ring pouring.The researches of which mentioned above all show that the monitoring method for the mijiashan bridge in this paper is scientifically reasonable.(4)The paper detailed introduced the risk analysis,the risk distinguish and the risk evaluation of the bridge construction phase.The risk ratio estimation ,loss estimation and the bridge risk matrix decision method based on the expert investigation is also detailed explained.the paper bring forward the blurring integrated evaluation method based on the analytic hierarchy process.(5)In this paper,the main risk risk factors are concluded and we can sed that the integral construction risks are moderate risks according to the analysis of Mijiashan bridge construction risk using the blurring integrated evaluation method based on the AHP.Aim at the main risk issues of the risk distinguish phase the risk control methods are proposed on mijiashan bridge construction.