Research On Replacement Method And Mechanical Properties Of Suspender Of Long Span Half-Through Arch Bridge

In recent decades,mid-support arch bridges have developed rapidly in my country.The suspender is the main force-transmitting component of the mid-support arch bridge.Because the design service life of the hanger rod is quite different from the design reference period of the bridge structure,the hanger rods of many bridges have been damaged.serious impact on bridges.Taking the replacement of the suspension rod of the mid-support arch bridge of the Beijing-Hangzhou Canal of Lianhuo Expressway as the engineering background,the method of the replacement of the suspension rod,the structural response during the replacement process and the errors existing in the replacement process are studied to ensure the safety and stability of the structure during the replacement process.and replacement effects.Firstly,according to the characteristics and application scope of the commonly used suspender replacement methods,and combined with the actual situation of the background bridge,the comparison and selection are carried out.The specific scheme of the project has been researched and designed,the construction process has been formulated,and the construction process has been clarified.The finite element simulation is used to analyze the construction stage of the suspender replacement process.Taking the bridge deck elevation and suspender cable force as the control indicators,the redistribution of suspender cable force,arch rib and cable force caused by bridge structure changes during the suspender replacement process is analyzed The structural response of the bridge deck system,such as vertical and transverse bridge displacement,has been studied and analyzed.The bridge deck steel truss hoisting method will have a great impact on the change of the cable force of the adjacent suspenders and the deflection of the nodes under the suspenders,especially for the mid-span suspension.It has a significant impact on the crack resistance of the bridge deck.Theoretical calculation and enhanced control must be carried out to ensure the safety and feasibility of the suspender replacement scheme.By analyzing the calculation error caused by the interference parameters in the method of measuring the cable force by the vibration frequency method,the calculation and correction method of the cable force by the static load test method or the oil pressure gauge method for calibrating the calculated length is studied and proposed,and this method is verified in the actual bridge.The accuracy meets the engineering requirements.Through the research on the construction step length of temporary suspender tension and old suspender cutting in the bridge deck steel truss pocket lifting method,it is concluded that the bridge deck steel truss pocket lifting method with variable step lengths has better structural response.Smaller and more conducive to the conclusion of the safety of the replacement process.The structural response caused by temperature,multi-point construction and construction load in the process of suspender replacement is analyzed.Through the analysis and processing of monitoring data,the error between the measured value and the theoretical value of the structural response is corrected,and the correct analysis and evaluation of the bridge deck elevation and the suspender cable force after the replacement of the suspender is carried out.After the replacement of the suspender,in order to meet the requirements of the suspender cable force and the bridge alignment,the influence matrix method is used to adjust the cable force of the local suspender,which provides a reference for the replacement of the suspender similar to the bridge type.