积分尺度和风速谱对桥梁抖振响应影响分析

Influences of integral scale and wind spectrum on buffeting response of long-span bridge

摘要:

为研究目前被动湍流风洞试验中无法准确模拟的湍流积分尺度对桥梁结构抖振响应的影响并合理评价风洞试验结果,本文采用抖振频域的计算方法,以典型的一座斜拉桥和一座悬索桥为例,结合主梁节段模型气动力参数风洞试验结果研究了积分尺度对节段模型抖振响应的影响．结果表明:当在小风速时,抖振响应随着积分尺度的增加而减小,而当风速超过一定限值后,抖振响应随着积分尺度的增加先增大后减小;通过对比风洞试验模拟与规范推荐积分尺度的差异,发现风洞试验在小风速时高估了抖振响应,而在大风速时则低估了抖振响应．本文还分析了各国规范中采用的几种水平和竖向风速谱对抖振响应的影响,结果表明几种水平向风速谱对抖振响应的影响可忽略不计,而不同竖向风速谱计算的抖振响应则存在一定差别．

Abstract:

To study the influence of integral scale on buffeting response of long-span bridge which cannot be taken into account in the passive turbulence wind tunnel test and to provide a reasonable evaluation of wind tunnel test result, taking a typical cable-stay bridge and a suspension bridge as samples and combining aerodynamic parameters of the section model in wind-tunnel test, the influence of turbulence integral scale and wind spectra on buffeting responses were studied in frequency domain. The results show that buffeting responses decrease with increase of integral scale at lower wind speed; while at higher wind speed, buffeting responses increase first and then decrease. After comparing the integral scales in wind tunnel test and in wind standard, the result shows that buffeting response in wind tunnel were overestimated at lower wind speed, but underestimated at higher wind speed. After comparing the influences of several frequently-adopted horizontal and vertical wind spectra on buffeting response, the result shows that the influence of different horizontal wind spectra can be neglected, but the influence of different vertical wind spectra should be taken into account.