大跨铝合金人行桥人致振动分析及舒适性评价

HUMAN INDUCED VIBRATION ANALYSIS AND VIBRATION COMFORT EVALUATION OF LONG-SPAN ALUMINUM ALLOY FOOTBRIDGE

铝合金人行桥因质轻、便于吊装施工等特点而成为人行桥设计新选择,但由于铝合金质轻、弹模低使得相比于钢结构人行桥更易出现振动舒适性问题。文中以三座大跨铝合金人行桥为对象,对行人质量影响下的结构振动基频及人致振动响应进行了分析,与同结构形式下钢结构人行桥进行了对比讨论,并结合各国振动舒适性规范对振动舒适性进行了评价。结果表明,铝合金人行桥因质量轻,相比于钢结构其振动基频对行人质量影响较敏感,设计中需考虑行人质量对降低结构基频的影响,从而使结构从超谐共振进入共振而产生过大振动,设计中建议适当提高结构振动基频以满足舒适性要求。

Aluminum alloy footbridge has become a new choice for footbridge design due to its light weight and easy construction. However, due to the light weight and low elastic modulus of materials, the problemof vibration comfort is more likely to occur than steel pedestrian bridges. In this paper, three large-span aluminum alloy footbridges are taken as examples to study the influence of pedestrian mass on the structural vibration fundamental frequency and human-induced vibration response. And the steel structure footbridges with the same formare compared. Combined with footbridge design standard of various countries, the vibration comfort of footbridge is evaluated. The results show that the aluminum alloy footbridge is sensitive to pedestrian mass compared with the steel structure because of its light weight. The reduction of structural fundamental frequency caused by pedestrian mass should be considered in the design, so that the structure enters resonance from superharmonic resonance and generates excessive vibration. Therefore, it is recommended to appropriately increase the structural fundamental frequency to meet the vibration comfort requirements.