Dynamic Response Of Corrugated Steel Web-Concrete Composite Box Girder Bridge Under Vehicle-Bridge Coupled

As the basic industry of the national economy,transportation occupies an important position in the development of human society,and is also an important component of the development of the national economy.In the era of rapid economic development,bridge construction has made significant contributions.In recent years,as a new type of bridge structure,corrugated web steel-concrete composite box girder bridges have attracted the attention of many scholars.However,the research on this type of structure is not comprehensive enough,especially based on the relative lack of research on the dynamic response characteristics of corrugated web steel-concrete composite box girders under vehicle bridge coupling.Therefore,based on the vehicle bridge coupling vibration theory,a series of studies have been conducted on the dynamic response of steel concrete simply supported box girder bridges with corrugated webs and three span continuous box girder bridges.The specific research content is as follows:(1)In order to conduct vehicle bridge coupling dynamic response analysis,a 40 m long and 10.5m wide corrugated web steel concrete simply supported box girder bridge in Lanzhou was taken as the research object.The dynamic response of the bridge was obtained through static and dynamic load tests,providing a basis for later verification of the rationality of the ANSYS model modeling method.Simulate sample curves under five flatness levels according to the unevenness level specification ISO-2005.A theoretical simulation method for vehicle bridge coupled vibration model is proposed,and the modal synthesis method is used to solve the equations.(2)Using Universal Mechanics dynamics software to conduct numerical simulation of a three-axle vehicle model,and using UM simulation,a vehicle bridge coupling vibration simulation system considering road roughness was established.The correctness of the system was confirmed through verification and comparison.(3)Through vehicle bridge coupled vibration simulation,the dynamic response characteristics of a corrugated web steel concrete simply supported box girder bridge under constant and variable speed driving of sports cars are analyzed.The displacement response and dynamic impact coefficient of the midspan section under different driving conditions are calculated,and the effects of vehicle parameters such as different driving speeds,different weights,different road roughness,and vehicle layout on the dynamic performance of the simply supported box girder are analyzed.The effects of different braking positions and accelerations on the dynamic response of bridges were compared.The research results show that pavement roughness has a significant impact on the dynamic response of bridges.The influence of vehicle weight on the dynamic deflection of bridge midspan is significant,while the impact coefficient is more complex.The dynamic impact coefficient corresponding to vehicle braking is significantly greater than the uniform speed result,and the impact of braking behavior occurring in the first half span of the bridge is greater than that occurring in the second half span.As the absolute value of braking acceleration increases,the impact coefficient increases.(4)The finite element analysis model of a corrugated web steel concrete continuous box girder bridge is established using ANSYS software.The vehicle bridge coupled vibration simulation is used to simulate the running and jumping motions of a three-axle vehicle,and the dynamic response characteristics are analyzed.According to the structural symmetry in structural mechanics,the left and middle span dynamic responses are selected for analysis.(5)The overall and local impact coefficient changes under different vehicle speeds are discussed,and the dynamic response changes of continuous beams under different actions of a single vehicle and vehicle flow are discussed.The effects of different vehicle heights and positions on the impact coefficient of bridges when vehicle jumps occur are studied.The research results show that the maximum deflection response and impact coefficient of multi span continuous beams are smaller than those of simply supported beams.The deflection of the displacement time history curve of the middle span is smaller than that of the side span,and the impact coefficients of the middle span are greater than those of the side span.The impact coefficient of the local measurement points near the free end of the concrete roof of the composite beam bridge is larger than the overall calculated value,and the closer it is to the free end of the cantilever,the greater the impact coefficient.The impact of vehicle jumping on the dynamic response of simply supported beam bridges is more obvious.The impact of vehicle jumping on the dynamic response and impact coefficient of bridges is greater than that of vehicles traveling at a uniform speed.