伸缩缝及支座病害对简支梁桥车致动力响应的影响研究

Study on the influence of expansion joints and bearing diseases on the vehicle-induced dynamic response of simply supported beam bridges

中小跨径桥梁在中国公路桥梁中占比大,其伸缩缝服役环境恶劣,易发生损伤造成过往车辆剧烈振动、桥梁支座损伤等病害。为探明伸缩缝、支座参数对简支梁桥车致动力响应的影响,建立了车⁃伸缩缝⁃桥梁耦合动力响应(VBCV⁃J)数值分析方法,并通过实测数据验证了该方法,进而开展了伸缩缝、支座参数影响规律的研究。研究结果表明:车速与车辆的振动密切相关,在车速较高、路面状况“一般”时,伸缩缝、梁端的冲击效应会超出规范值。伸缩缝中梁高于路面会导致该部件的冲击效应增大明显,反之则有所减小;而伸缩缝中梁高于或低于路面,均会造成该桥梁端冲击效应增大。伸缩缝弹性支撑刚度的降低、主梁边支座脱空均会引起伸缩缝、主梁梁端的冲击效应增大。支座刚度降低则主要导致主梁整体的冲击效应增大。伸缩缝的破损不仅影响自身冲击效应,还会大幅增大简支梁桥梁端构件的冲击作用,在设计和养护中,应对伸缩缝及梁端构件给予足够的重视。

Medium and small span bridges make up a large proportion of highway bridges in China.Due to harsh service condi⁃tions,the expansion joints are prone to diseases,which can exacerbate vehicle vibrations,and subsequently lead to the damage of the end bearings and other components.In order to study the influence of expansion joint and bearing parameters on the vehicle-in⁃duced dynamic response of simply supported beam bridge,this paper establishes a numerical analysis method of vehicle-expansion joint-bridge coupling dynamic response(VBCV-J).The effectiveness of VBCV-J analysis method is verified using measured data,followed by an investigation the influence of expansion joint and support parameters.The results show that:The speed is closely re⁃lated to vehicle vibration.When the vehicle speed is high and the Road Surface Condition(RSC)is“normal”,the impact effect of vehicles on expansion joints and the ends of beams can exceed the specified values..If the girder in the expansion joint is higher than the pavement,the impact on the expansion joint will significantly increase,conversely,it will decrease.When the girder in the ex⁃pansion joint is higher or lower than the road surface,the impact at the end of the main beam will increase.A reduction in the sup⁃port stiffness of the expansion joint or a void in the side support of the main beam will significantly increase the impact effect on both the expansion joint and the end of the main beam.A decrease in the stiffness of the main beam support primarily results in an increased impact on the entire main beam.Damage to the expansion joints not only affects their own impact,but also greatly in⁃creases the impact on the end members of the simply supported beams.During design and maintenance,sufficient attention should be given to the end members of the beams.