Dynamic Stress Amplification Caused by Sudden Failure of Tension Members in Steel Truss Bridges
Dynamic Stress Amplification Caused by Sudden Failure of Tension Members in Steel Truss Bridges
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DOI：
10.1061/(asce)st.1943-541x.0000338
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
Y. Goto;N. Kawanishi;I. Honda
中科院分区：
文献类型：
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作者：
Y. Goto;N. Kawanishi;I. Honda
通过精确的动力响应分析，研究了桁架桥张拉构件突然失效引起的动应力放大特性。动应力放大的主要来源有两种。主要影响可归因于从故障点开始的纵向应变波传播。二次冲击是平衡从失效前状态向失效后状态动态转变的结果。然而，初始冲击的影响很小，在计算用于结构冗馀分析的冲击系数时可以忽略不计。结构中关键构件的冲击系数几乎是一个恒定值，取值范围为1.4~1.8，假定结构阻尼为5%，采用单自由度模型计算现有的冲击系数为1.854。为了避免繁琐的动力响应分析，采用均方根模组合方法近似计算冲击系数。就实际目的而言，这样计算的冲击系数是相当准确的。
The property of dynamic stress amplification resulting from the sudden failure of a tension member in a truss bridge is investigated by a precise dynamic response analysis. The primary sources of the dynamic stress amplification are from two types of impacts. The primary impact is attributable to longitudinal strain wave propagation from a failure point. The secondary impact is a result of the dynamic transition of equilibrium from a prefailure to a postfailure state. However, the effect of the primary impact is so small that it can be ignored in evaluating the impact coefficients used for the structural redundancy analysis. The impact coefficients for critical members in a structure take almost a constant value that ranges from 1.4 to 1.8, for which 5% structural damping is assumed, following the single degree of freedom model employed to evaluate the existing impact coefficient of 1.854. To avoid a cumbersome dynamic response analysis, the root mean square mode combination method is applied to calculate approximately the impact coefficients. The impact coefficients so calculated are moderately accurate for practical purposes.