波纹钢腹板组合箱梁应力相关阻尼特性研究

基于应力相关材料阻尼理论，选择波纹钢腹板组合箱梁这一新型钢、混组合桥梁结构，通过波纹钢板和钢筋混凝土的单位体积损耗因子，由能量法推导求得波纹钢腹板组合箱梁的损耗因子公式。结合有限元计算的各个单元的应力得到损耗因子，根据一个振动周期能量耗散相等原理，求得等效阻尼比，并将其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材料阻尼值不是一个固定值，它是随着应力水平的提高而增大。在自由振动和车辆荷载激励状态下，波纹钢腹板组合箱梁的等效阻尼比建议取为0.3%。提出的损耗因子公式和等效阻尼比的计算可为波纹钢腹板组合箱梁桥动力分析中阻尼的取值提供参考。

Stress-related damping characteristic of a composite box-girder with corrugated steel webs

A box girder with corrugated steel webs is a new steel-concrete composite bridge structure.Based on the theory of stress-related material damping,using the unit volume dissipation factor of corrugated steel webs and reinforced concrete,the dissipation factor formula of a composite box girder with corrugated steel webs was deduced through the energy method.The dissipation factor was obtained by combining the stress of each element computed with the finite element method.The equivalent damping ratio was calculated according to the equal energy dissipation in one vibration cycle,and compared to the measured results.The analysis results showed that the material damping of the composite box-girder with corrugated steel webs is not a fixed value;it increases with increase in stress level;under free vibration and vehicle load excitation,the damping ratio of the composite box-girder with corrugated steel webs is suggested as 0.3%.The formula of dissipation factor and calculation of equivalent damping ratio here provided a reference for selecting damping value in dynamic analysis of composite box girder bridges with corrugated steel webs.