西安建筑科技大学学报(自然科学版)

为了研究运营过程中不同人流量对于柔性人行悬索桥自振特性及人致振动响应的影响,以某地锚式(70+360+60)m柔性人行悬索桥为工程实例,采用Midas/Civil软件建立了有限元模型,计算了不同人流量下该人行悬索桥的自振频率.参考德国人行桥规范EN03-2007,计算了同步人群谐波荷载下主梁的竖向及侧向加速度,并进行了行人舒适度评价.计算结果表明:柔性人行悬索桥自振基频较低,行人步频所对应的均为较高阶的振动模态; 考虑人群质量后,主梁的各阶自振频率和行人谐波荷载下的加速度均较未考虑时减小,且随着人流量的增加,主梁的最大竖向及侧向加速度极值均随之增大.人群质量对主梁竖向和侧向加速度的影响不同,其结果与行人竖向和侧向谐波荷载不同的折减系数规律相关; 考虑人群质量后,该悬索桥在人流量为0.5人/m2时,行人处于很舒适状态,在1.0～2.0人/m2处于中等舒适状态.

In order to study the influence of different pedestrian flow on the natural vibration characteristics, vertical and lateral acceleration of suspension footbridges during operation, the finite element model of a(70+360+60)m ground-anchored suspension footbridge was established using Midas/Civil software, and the natural vibration frequencies were calculated. Based on the German pedestrian bridge standard EN03-2007, the vertical and lateral acceleration of the main girder under the synchronous crowd harmonic load were obtained, and the pedestrian comfort was evaluated. Results indicate that the natural vibration frequencies of the flexible suspension footbridge are rather low due to the flexibility of the bridge, which makes the pedestrian step frequency close to high-order vibration modes. Pedestrian mass makes the natural frequencies and the acceleration of the main girder decrease, and the maximum vertical and lateral acceleration improve with the increasing of the pedestrian mass. The pedestrian mass has different influence on the vertical and lateral acceleration of the main girder, which is related with the different reduction factor of the vertical and lateral pedestrian harmonic load. Considering the pedestrian mass, the suspension footbridge in this paper is in very comfort state under the pedestrian flow of 0.5 P/m2, and in medium comfort state under the pedestrian flow of 1.0～2.0 P/m2.

引言
1 工程概况
2 有限元模型及自振特性分析
3 柔性悬索桥人致振动响应研究
4 结论

图1 桥梁布置图(单位:m)<br/>Fig.1 Bridge layout(unit:m)

图1 桥梁布置图(单位:m)
Fig.1 Bridge layout(unit:m)

图2 主梁横断面构造图(单位:mm)<br/>Fig.2 Cross section of the main girder(unit:mm)

图2 主梁横断面构造图(单位:mm)
Fig.2 Cross section of the main girder(unit:mm)

图3 悬索桥全桥有限元模型<br/>Fig.3 Finite element model of suspension bridge

图3 悬索桥全桥有限元模型
Fig.3 Finite element model of suspension bridge

表1 不同人流量下的结构自振频率/Hz<br/>Tab.1 Natural vibration frequency under different pedestrian flow/Hz

表1 不同人流量下的结构自振频率/Hz
Tab.1 Natural vibration frequency under different pedestrian flow/Hz

图4 竖向折减系数<br/>Fig.4 Vertical reduction factor

图4 竖向折减系数
Fig.4 Vertical reduction factor

图5 侧向折减系数<br/>Fig.5 Lateral reduction factor

图5 侧向折减系数
Fig.5 Lateral reduction factor

表2 行人谐波荷载计算参数<br/>Tab.2 Parameters of the harmonic pedestrain load

表2 行人谐波荷载计算参数
Tab.2 Parameters of the harmonic pedestrain load

图6 1.5人/m2时的主梁跨中竖向加速度时程(fv=1.646 Hz)<br/>Fig.6 Time-midspan vertiacal accleration of the main girder under 1.5 p/m2

图6 1.5人/m2时的主梁跨中竖向加速度时程(fv=1.646 Hz)
Fig.6 Time-midspan vertiacal accleration of the main girder under 1.5 p/m2

图7 1.5人/m2时的主梁跨中侧向加速度时程(fh=0.734 Hz)<br/>Fig.7 Time-midspan lateral acceleration of the main girder under 1.5 p/m2

图7 1.5人/m2时的主梁跨中侧向加速度时程(fh=0.734 Hz)
Fig.7 Time-midspan lateral acceleration of the main girder under 1.5 p/m2

图8 不同人流量下的主梁最大竖向加速度<br/>Fig.8 Maximum vertical acceleration of the main girder under pedestrian flow

图8 不同人流量下的主梁最大竖向加速度
Fig.8 Maximum vertical acceleration of the main girder under pedestrian flow

图9 不同人流量下的主梁最大侧向加速度<br/>Fig.9 Maximum lateral acceleration of the main girder under different pedestrian flow

图9 不同人流量下的主梁最大侧向加速度
Fig.9 Maximum lateral acceleration of the main girder under different pedestrian flow

图10 行人谐波荷载加载方式<br/>Fig.10 Loading of harmonic pedestrian load

图10 行人谐波荷载加载方式
Fig.10 Loading of harmonic pedestrian load

图11 主梁最大加速度极值随人流量的变化<br/>Fig.11 Ultimate value of the maximum acceleration of the main girder vs. pedestrian flow

图11 主梁最大加速度极值随人流量的变化
Fig.11 Ultimate value of the maximum acceleration of the main girder vs. pedestrian flow

表3 人行桥加速度舒适度指标<br/>Tab.3 Comfort indexes of the acceleration for the pedestrain bridge

表3 人行桥加速度舒适度指标
Tab.3 Comfort indexes of the acceleration for the pedestrain bridge

表4 本文人行悬索桥行人舒适度评价结果<br/>Tab.4 Comfort assessment for the pedestrain suspension bridge in this paper

表4 本文人行悬索桥行人舒适度评价结果
Tab.4 Comfort assessment for the pedestrain suspension bridge in this paper

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备注

引言

1 工程概况

2 有限元模型及自振特性分析

3 柔性悬索桥人致振动响应研究

4 结论

期刊信息