考虑P-Δ效应的弹塑性反应谱归一化

蔡志恒, 童根树

浙江大学土木工程系



摘要:

为了获得考虑P-Δ效应的强度折减系数R谱和弹塑性动力放大系数β谱,对理想弹塑性(EPP)滞回模型的单自由度体系在地震作用下的响应进行分析,得到不同场地类别、结构自振周期、位移延性、阻尼比和二阶效应的反应谱,并利用2个特征周期Tga和TgR对横轴进行标准化处理.结果表明:周期标准化的R谱和β谱很好地保留了特征周期处的峰值特性,延性、结构周期、二阶效应和阻尼比都对β谱起着显著影响,利用β谱来计算弹塑性地震力,要比采用R来对弹性地震力折减的结果更加理想.

关键词:  理想弹塑性滞回模型  地震力折减系数  动力放大系数  特征周期  二阶效应

DOI：10.11918/j.issn.0367-6234.2011.06.026

分类号:O344.3

基金项目:国家自然科学基金资助项目(51078328)



Inelastic spectrum normalization considering P-Δ effects

CAI Zhi-heng, TONG Gen-shu

Department of Civil Engineering,Zhejiang University,310058 Hangzhou,China

Abstract:

To investigate strength reduction factor R and dynamic magnification factor β,dynamic response of single degree of freedom(SDOF) elastic-perfectly plastic(EPP) hysteretic system are analysed.The influence of site types,natural vibration periods,displacement ductilities,damping ratios and P-Δ effect coefficients are taken into account.The characteristic periods Tga and TgR are used to normalize the R spectra and β spectra.Results indicate that ductility,damping ratio and P-Δ effect coefficient all have obvious effect on R and β.β produces more ideal effect than R on elastic-plastic seismic force calculation.

Key words:  elastic-perfectly plastic hysteretic model  seismic force reduction factor  dynamic magnification factor  characteristic period  P-Δ effect