Research On Construction Monitoring And Seismic Response Of High-pier And Long-span Continuous Rigid Frame Bridge In Reservoir Area

With the implementation of the Western Development Strategy,the topography of the southwestern region of my country is complex,ravines are vertical and horizontal,and the construction of large-span continuous rigid-frame bridges is increasing.In order to cross the complex terrain,the pier heights of continuous rigid-frame bridges are also getting higher and higher.The cantilever pouring construction method is one of the most commonly used construction methods for this type of bridge.In the cantilever pouring method,multiple structural system conversions are required.In order to ensure the safety of construction,smooth bridge alignment and meet design requirements,bridge construction control is indispensable.Under the action of earthquake,the interaction between deep-water structure and water will have a non-negligible effect on the dynamic characteristics of the structure,so it should be considered in the design and calculation.This paper controls the Changzhenggou Bridge(63m+110m+63m)during the construction process based on the characteristics of this type of bridge and its construction safety.The seismic response characteristics under the influence of the effect are analyzed.The main research contents are as follows:(1)Summarize the development research status of construction control of high-pier and long-span continuous rigid frame bridges at home and abroad.At the same time,it briefly introduces the characteristics of the seismic response of deep-water bridges and lists the research results at home and abroad in recent years.(2)Use MIDAS/Civil as a tool to establish a three-dimensional numerical model of the Changzhenggou Bridge,conduct simulations at various stages of construction,extract theoretical values such as section stress and vertical mold elevation,based on adaptive control theory,based on least squares control method,ahead of schedule Considering various factors that affect construction control,guide on-site construction,so that the completed bridge has a smooth line shape,reasonable stress,and errors within the allowable range of the code,ensuring reliable bridge construction quality.(3)This paper summarizes the more widely used research methods of hydrodynamic effects.Based on the actual application of this article,the representative methods are described in detail,which provides the theoretical basis and calculation basis for the pier-water coupling under seismic excitation.(4)Using ADINA software as a modeling tool,the potential fluid unit is used to simulate the water body,the fluid-solid coupling principle and the additional mass method are used to establish the pier model—the potential fluid model and the additional mass model,and the appropriate seismic wave is selected according to the site type of the Changzhenggou Bridge.,Analyze the dynamic characteristics and seismic response of bridge piers affected by water under different seismic waves.(5)The potential fluid model is used to analyze the influence of different water depths on the natural vibration characteristics of the bridge piers.The study shows that the existence of water will reduce the natural vibration frequency of the model.According to the calculation results,it can be obtained that the higher the water height around the model,the natural frequency of the model The greater the degree of reduction.(6)Under the action of earthquake,the seismic response of the additional mass model using the highway seismic code method and the model using the potential fluid theory are compared and analyzed.The dynamic response results obtained by the two methods are consistent,but the values of the two results are the same.There is a big difference between them,and the additional quality method is biased towards safety.(7)Based on the calculation results of the potential fluid model,by analyzing the dynamic characteristics of the bridge pier model under different water depths,the effectiveness of the Wang Baoxi simplified formula method and the highway seismic code method are compared and verified.The error rate of the highway code method under different water depths Slightly higher than the error rate of Wang Baoxi’s simplified formula.