基于复频率的波纹钢腹板组合箱梁桥等效阻尼比计算

Calculation of Equivalent Damping Ratio of Composite Box Girder Bridge with Corrugated Steel Webs Based on Complex Frequency

基于复频率和滞后阻尼系数的关系,选择新型钢-混组合桥梁结构———波纹钢腹板组合箱梁桥,利用等效前后复频率相等的原理,推导出了波纹钢腹板组合箱梁桥等效阻尼比的计算公式。建立波纹钢腹板组合箱梁实桥有限元模型,通过实际波纹钢腹板简支箱梁和连续箱梁计算得其等效阻尼比并与实测结果进行比较。分析结果表明:波纹钢腹板组合箱梁桥的等效阻尼比公式的计算结果与实测结果吻合良好;提出的计算方法简单实用,能够满足工程中使用的要求。提出的等效阻尼比的计算公式可以有效计算波纹钢腹板组合箱梁桥的等效阻尼比,为动力分析中阻尼比的取值提供参考。

Based on the relationship between complex frequency and hysteresis damping coefficient, composite box girder bridge with corrugated steel webs, a new type of steel-concrete bridge structure, was chosen to derive the formula of its equivalent damping ratio by the principle of the complex frequency keeping the same before and after equivalent. The finite element model of composite box girder bridge with corrugated steel webs was built. The equivalent damping ratios of actual composite simply supported box girder and continuous box girder with corrugated steel webs were calculated, and compared with the measured values. The results show that （ 1 ） the calculated value of the equivalent damping ratio of composite box girder bridge with corrugated steel webs meets the measured results well; （2） the suggested computing method is simple and practical, and can meet the requirements of engineering practice. The suggested computational formula of the equivalent damping ratio can be used to compute the equivalent damping ratio of composite box girder bridge with corrugated steel webs accurately, which can provide a reference for the value of damping ratio in dynamic analysis.