Assessment of RC columns subjected to horizontal and vertical ground motions recorded during the 2009 L'Aquila (Italy) earthquake
Assessment of RC columns subjected to horizontal and vertical ground motions recorded during the 2009 L'Aquila (Italy) earthquake
复制标题
DOI：
10.1016/j.engstruct.2011.01.023
复制
发表时间：
2011-05-01
影响因子：
5.5
通讯作者：
Manfredi, G.
中科院分区：
文献类型：
--
作者：
Di Sarno, L.;Elnashai, A. S.;Manfredi, G.
在最近的地震之后，有大量的现场证据表明，一些现有建筑物的倒塌是由地震地面运动的垂直分量的影响造成的。这种实地证据尚未得到全面的分析评估和实验测试的支持。本文对2009年意大利L地震记录的钢筋混凝土构件在水平(HGM)和竖向(VGM)地震作用下的地震反应进行了初步分析。梁柱的归一化轴向荷载以及水平和垂直地面加速度的峰值地面加速度比被认为是评估水平和垂直地面运动(HVGM)下结构部件和系统的最重要的参数。样本模型包括悬臂钢筋混凝土柱和一个两层、两个开间的平面框架，设计用于重力荷载。分析的结构响应量以轴向荷载、轴向变形、弯矩-轴向荷载相互作用和剪力需求/能力比的形式表示。研究发现，高强高强混凝土柱的轴向荷载变化较大，尤其是在受压方面。对于框架结构中与实际钢筋混凝土柱相对应的归一化轴向荷载(Nu)值，例如归一化轴向荷载Nu>；0.10，压缩荷载的平均增幅在174%(Nu=0.20)到59%(Nu=0.50)之间。对于较高的归一化轴向荷载，计算的轴向荷载-弯矩对超出了门槛相互作用曲线，反过来，RC构件可能会失效。剪力供需比也受到柱子中轴向荷载波动较大的不利影响。计算了中低轴向重力预紧柱的净拉力。在多层框架建筑中，高强玻璃钢对中柱的反应有很大影响。框架体系可靠的抗震性能评估要求在分析中考虑HGM和VGM的组合。需要进一步的试验和数值研究来建立有效的力学模型来评估在用钢筋混凝土框架结构构件在地震荷载作用下的抗剪能力。(C)2011爱思唯尔有限公司。保留所有权利。
In the aftermath of recent earthquakes there has been substantial field evidence demonstrating that the collapse of several existing structures was caused by the effects of the vertical component of seismic ground motions. Such field evidence has not yet been supported by comprehensive analytical assessment and experimental tests. The present work focuses on preliminary analyses of the seismic response of reinforced concrete (RC) members subjected to horizontal (HGMs) and vertical (VGMs) ground motions recorded during the 2009 L'Aquila (Italy) earthquake. Normalised axial loads in beam-columns as well as the peak ground acceleration ratios between horizontal and vertical ground accelerations are emphasised as they are considered parameters of paramount importance for the assessment of structural components and systems subjected to combined horizontal and vertical ground motions (HVGMs).Results of extensive parametric nonlinear dynamic analyses carried out on simplified structural models are discussed in detail. The sample models comprise cantilever RC columns and a two-storey, two-bay plane frame designed for gravity loads. The structural response quantities for the performed analyses are expressed in terms of axial loads, axial deformations, bending moment-axial load interaction and shear demand/capacity ratios. It is found that the variation of axial loads is significant in columns under HVGMs, especially in compression. For values of normalised axial loads (nu) corresponding to actual RC columns in framed building structures, e.g., normalised axial load nu > 0.10, the average increase of the compression load ranges between 174% (nu = 0.20) and 59% (nu = 0.50). For high values of normalised axial loads the computed axial load-bending moment pairs lie beyond the threshold interaction curves and, in turn, the RC members may fail. The shear demand-to-supply ratio is also detrimentally affected by the high fluctuations of axial loads in the columns. Net tensile forces were computed for columns with low-to-moderate axial gravity preload. In multi-storey framed buildings, the response of central columns is significantly affected by the HVGMs. Reliable seismic performance assessment of framed systems requires that combined HGMs and VGMs should be accounted for in the analyses. Further experimental and numerical research is needed to formulate efficient mechanical models to evaluate the shear capacity of structural members of existing RC framed buildings under earthquake loading. (C) 2011 Elsevier Ltd. All rights reserved.