钢箱梁曲线多跨人行桥的振动舒适度分析

Vibration Comfort Analysis of Curved Steel Box Girder Pedestrian Bridges

曲线连续梁人行桥与单跨式人行桥相比,具有更复杂的几何特征及结构动力特性,易引发舒适度问题。目前国内外规范少有针对曲梁人行桥的振动响应计算方法,借鉴国内外典型的人行桥舒适度设计规范旨在讨论现有计算方法对于该曲线多跨桥舒适度验算的适用性。以一座钢箱梁曲线人行桥为例,基于实测结果校对了有限元模型,并按照规范对该人行桥舒适度评价结果进行了比较,同时使用简化的单自由度方法对有限元计算结果进行验证。结果表明:低于TC5的交通等级限制下,该人行桥可以基本满足舒适度要求;由于多跨曲线人行桥的高阶自振频率分布密集,舒适度设计时宜考虑步行荷载二阶分量引起的结构高频共振产生的影响;德国EN03规范方法对该人行桥振动舒适度设计更有优势。

Compared to single-span pedestrian bridges,curved continuous beam pedestrian bridges exhibit more complex geometric and structural dynamic characteristics,which can lead to comfort issues.Currently,there are few vibration response calculation methods specifically addressing curved beam pedestrian bridges in domestic and international standards.This study aims to discuss the applicability of existing calculation methods for evaluating the comfort of curved multi-span bridges by drawing on typical design specifications for pedestrian bridge comfort from both domestic and international sources.Taking the steel box girder curved pedestrian bridge as an example,the finite element model was calibrated based on measured results.The comfort evaluation results of the pedestrian bridge were compared against the specifications,and the finite element results were validated using a simplified single-degree-of-freedom method.The results indicate that under traffic level limitations lower than TC5,the pedestrian bridge can generally meet the comfort requirements.Due to the dense distribution of higher-order natural frequencies in multi-span curved pedestrian bridges,the influence of high-frequency resonance caused by the second component of pedestrian load should be considered in comfort design.