采用无线测力鞋垫实测了24人次372条跑步荷载,计算了每条时程所对应的单自由度系统的加速度反应谱,取每位测试者所有的计算反应谱曲线的包络线为其代表谱线,在分析所有代表谱线特点的基础上提出了设计反应谱的形式及其数学表达式,包含六个部分:三个平台段以及它们之间的连接线。由试验数据的分析确定了不同阻尼比和保证率下各部分设计谱参数的取值,并讨论了结构跨度、跑步步距、高阶振型和边界条件对反应谱的影响,提出了不同谱代表值之间的转换关系。该文给出了设计反应谱的详细使用步骤并通过工程实例验证了其可行性。
This paper investigates the acceleration response spectrum approach for predicting dynamic responses of long-span structures due to individual running loading. The wireless in-insole was used to measure the individual running loads due to 372 records from 24 test subjects. Each record was applied to a single-degree-of-freedom system with various frequencies and damping ratios to determine its responses spectrum. The envelop curve of all responses spectra of records from the same subject was taken as his/her representative spectrum curve. Based on all the 24 representative curves, a design spectrum has been suggested, which comprises the first, second and third plateau and linear/exponential linking lines between each plateau. Spectrum parameters for different damping ratios and guarantee rates were determined based on the statistical analysis of experimental data. Furthermore, the effects of several factors on the spectrum were explored by numerical simulations and correction coefficients were accordingly developed, including floor span, multi-modes and boundary conditions. The exchange rules between different spectrum's predictions, e.g. peak value and root-mean-squares, were also established. Finally, a detailed application procedure of the spectrum approach was presented whose applicability and reliability have been validated by the comparisons with field measurements.