基于随机车流的大跨度组合梁桥人非通道车致振动舒适度研究

Research on Comfort Level of Vehicle-induced Vibration in Pedestrian and Non-motored Vehicle Passages of Long-span Composite Beam Bridges Based on Random Traffic Flow

摘要:

为评估大跨度桥梁在随机车流作用下外挑人非通道的行人舒适度，以一座主跨180 m的钢箱组合连续梁桥为背景，开展了车致振动响应分析与舒适度评价。首先，基于分离迭代法建立车桥耦合振动分析模型，并依据相关标准确立以频率计权均方根加速度为核心的评价体系；其次，考虑路面粗糙度的随机性，模拟5种交通流量下的随机车流过桥工况，分析人非通道的振动响应分布规律，并定量评价行人舒适度。结果表明：车流引起的人非通道振动主要集中在主梁分离段，远离主梁的区域振动响应存在放大效应；在预测远期交通流量范围内，人非通道各点的频率计权均方根加速度均小于0.06 m/s2，行人舒适度评价均为“未感不适”。因此，该桥型结构在设计交通流下能够满足行人舒适度要求。

Abstract:

To evaluate the pedestrian comfort of the cantilevered pedestrian and non-motored vehicle passages of long-span bridge under random traffic flow, the vehicle-induced vibration response analysis and the comfort assessment are conducted on a steel-box composite continuous beam bridge with a main span of 180 m. A vehicle-bridge coupled vibration analysis model is established based on the separate iteration method, and an evaluation system centered on frequency-weighted root-mean-square acceleration is developed in accordance with relevant standards. Considering the randomness of pavement roughness, five traffic flow scenarios are simulated for vehicles crossing the bridge. The distribution patterns of vibration responses of the pedestrian and non-motored vehicle passage are analyzed, and the pedestrian comfort is quantitatively evaluated. The results show that the vehicle-induced vibration of the pedestrian and non-motored vehicle passage is mainly concentrated in the separated section of the girder, and the vibration response in the area far from the girder has an amplification effect. Within the predicted long-term traffic flow range, the frequency-weighted root-mean-square acceleration at all points of pedestrian and non-motored vehicle passage is all less than 0.06 m/s2, and the pedestrian comfort is rated as “no discomfort”. Therefore, this type of bridge structure can meet the pedestrian comfort requirements under the design traffic flow.