许柳韵, 周志光. 软土地基超高层结构条件均值谱应用研究[J]. 工程力学, 2021, 38(S): 228-236. DOI: 10.6052/j.issn.1000-4750.2020.05.S041
引用本文: 许柳韵, 周志光. 软土地基超高层结构条件均值谱应用研究[J]. 工程力学, 2021, 38(S): 228-236. DOI: 10.6052/j.issn.1000-4750.2020.05.S041
XU Liu-yun, ZHOU Zhi-guang. APPLICATION OF CONDITIONAL MEAN SPECTRUM ON SUPER HIGH-RISE BUILDING IN SOFT SOILS[J]. Engineering Mechanics, 2021, 38(S): 228-236. DOI: 10.6052/j.issn.1000-4750.2020.05.S041
Citation: XU Liu-yun, ZHOU Zhi-guang. APPLICATION OF CONDITIONAL MEAN SPECTRUM ON SUPER HIGH-RISE BUILDING IN SOFT SOILS[J]. Engineering Mechanics, 2021, 38(S): 228-236. DOI: 10.6052/j.issn.1000-4750.2020.05.S041

软土地基超高层结构条件均值谱应用研究

APPLICATION OF CONDITIONAL MEAN SPECTRUM ON SUPER HIGH-RISE BUILDING IN SOFT SOILS

  • 摘要: 准确可靠的预测地震作用下的结构响应要求选择合适的输入地震动,地震动的选择最主要的步骤在于确定目标谱以及根据目标谱进行匹配、调幅的方法。常用的一致危险谱存在过于保守的问题,根据地震危险性的合成和分解而提出的条件均值谱克服了这一弊端,因而受到国内外广泛的关注。但是就目前而言,对于条件均值谱的研究在软土地基以及超高层结构方面的研究并不完善。该文以上海地区超高层建筑上海中心为主要研究对象,通过概率地震危险性分析确定了其第一自振周期点处50年超越概率10%的谱加速度值;以此为目标值进行地震危险性分解,结合上海地区衰减关系确定了上海场地平均贡献地震以及第一自振周期点对应的谱形参数,从而创建了条件均值谱。与上海规范反应谱进行对比,并运用同时匹配目标谱均值和标准差的方法进行选波。结果表明:以条件均值谱为目标谱选择的地震动离散性更大,对于长周期结构,以上海规范反应谱为目标谱偏于保守。

     

    Abstract: Accurate and reliable prediction of structural performance under earthquake requires appropriate ground motion selection. The most important steps are to specify the target spectrum and to select the matching and scaling methods correspondingly. The inherit problem of the commonly utilized Uniform Hazard Spectrum (UHS) is too conservative, while Conditional Mean Spectrum (CMS) based on synthesis and de-aggregation of seismic hazard overcomes this drawback, which has been widely concerned round the world. However, some issues on the application of CMS on soil zones and super high-rise structures remain unaddressed. This paper focuses on the typically super high-rise building in Shanghai site, Shanghai Tower. Based on the Probabilistic Seismic Hazard Analysis, the spectral acceleration at the first fundamental period with 10% of exceedance in 50 years was determined. Then, de-aggregation of probability seismic hazard was carried out to determine the mostly contributed ground motion and spectral parameters at the first fundamental period of SHT in accordance with the attenuation of Shanghai site. CMS can be created and compared with Shanghai Standard Spectrum when utilized as the target spectrum to select ground motions by matching target mean and variance, and inter-storey drift ratios are compared. Results show that ground motion suite targeted on CMS has larger dispersion, and Shanghai Standard Spectrum is conservative to long-period structures.

     

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