基于一致可靠度的地震动记录样本容量确定方法研究          下载免费PDF全文

陈波  温增平 《地震工程学报》2018,40(6):1295-1305

确定地震动输入样本容量是开展结构动力地震反应分析的重要环节,目前国内外关于地震动输入样本容量的讨论往往忽略或尚难以定量考虑结构地震反应估计的可靠度水平。以一实际钢筋混凝土框架结构为例,首先分析在大样本地震动作用下结构非线性地震反应的统计特征,研究估计结构地震反应时取样本最大值和平均值的差异,然后借助于假设检验分析结构地震反应的概率分布模型,给出基于一致可靠度的地震动样本容量确定方法,并对比分析单周期点、多周期点、谱值匹配调整地震动及人工合成地震动对样本容量需求的影响,为保证在小样本地震动输入下结构地震反应估计值满足给定可靠度和容许误差提供分析方法和判断依据。本文方法适应于定量确定不同结构类型和不同地震强度水平下的地震动样本容量需求,对建筑结构抗震性能评估及设计规范研究有一定意义。  相似文献   

2016年8月24日意大利中部M_W6.2地震强地面运动特征分析          下载免费PDF全文

冯继威  李山有  宋晋东 《地震工程学报》2018,40(2):316-328

对意大利国家强震台网在2016年8月24日获得的其中部拉齐奥大区阿库莫利市发生的M_W6.2地震强震动三分向记录进行处理和分析。完成原始数据基线校正、滤波等基本数据处理,回归此次地震动幅值衰减规律,发现其整体与ITA08及BA08的衰减趋势一致,但远场实际值低于预测值,不同场地条件下的衰减特性与ITA10一致,近震源幅值较大,且方向性明显;计算并回归分析几种持时,与全球经验预测方程均基本吻合;比较4个幅值较大的近震源台站的反应谱,发现其明显高于欧洲抗震设计规范中的设计反应谱。结合此次震害特点,该地区在实际建设中仍需提高抗震设防能力,以确保安全性等级。  相似文献   

Review on the study of topographic effect on seismic ground motion          下载免费PDF全文

Hong Zhou 《地震科学（英文版）》2018,31(2):110-116

Topographic effect study is a very important research topic in seismology, seismic engineering,earthquake engineering, engineering earthquake construction and engineering seismology. This paper focuses on its present development status. Post-earthquake investigation has found that the existence of topography caused more serious earthquake damage. The actual seismographs also recorded the topographic amplification effect of 6 to 7 times and even more than 10 times. Numerical simulation is an important technique to study topographic effect, which complements the lack of observed records. However researches on 3-D topographic effect are not enough and need to be studied deeper. To find the main influence factors and the quantitative relationship between topography and ground motion are required very urgently. Obviously the achievements not only can be applied in the earthquake resistant design, but also can provide the quantitative pre-earthquake disaster prediction and quantitative post-earthquake disaster evaluation.  相似文献   

Validation of the SCEC Broadband Platform simulations for tall building risk assessments considering spectral shape and duration of the ground motion          下载免费PDF全文

Nenad Bijelić  Ting Lin  Greg G. Deierlein 《地震工程与结构动力学》2018,47(11):2233-2251

Earthquake simulation technologies are advancing to the stage of enabling realistic simulations of past earthquakes as well as characterizations of more extreme events, thus holding promise of yielding novel insights and data for earthquake engineering. With the goal of developing confidence in the engineering applications of simulated ground motions, this paper focuses on validation of simulations for response history analysis through comparative assessments of building performance obtained using sets of recorded and simulated motions. Simulated ground motions of past earthquakes, obtained through a larger validation study of the Southern California Earthquake Center Broadband Platform, are used for the case study. Two tall buildings, a 20‐story concrete frame and a 42‐story concrete core wall building, are analyzed under comparable sets of simulated and recorded motions at increasing levels of ground motion intensity, up to structural collapse, to check for statistically significant differences between the responses to simulated and recorded motions. Spectral shape and significant duration are explicitly considered when selecting ground motions. Considered demands include story drift ratios, floor accelerations, and collapse response. These comparisons not only yield similar results in most cases but also reveal instances where certain simulated ground motions can result in biased responses. The source of bias is traced to differences in correlations of spectral values in some of the stochastic ground motion simulations. When the differences in correlations are removed, simulated and recorded motions yield comparable results. This study highlights the utility of physics‐based simulations, and particularly the Southern California Earthquake Center Broadband Platform as a useful tool for engineering applications.  相似文献   

Evaluation of ASCE 7 equations for designing acceleration‐sensitive nonstructural components using data from instrumented buildings     

Hamidreza Anajafi  Ricardo A. Medina 《地震工程与结构动力学》2018,47(4):1075-1094

This study uses instrumented buildings and models of code‐based designed buildings to validate the results of previous studies that highlighted the need to revise the ASCE 7 F_p equation for designing nonstructural components (NSCs) through utilizing oversimplified linear and nonlinear models. The evaluation of floor response spectra of a large number of instrumented buildings illustrates that, unlike the ASCE 7 approach, the in‐structure and the component amplification factors are a function of the ratio of NSC period to the supporting building modal periods, the ground motion intensity, and the NSC location. It is also shown that the recorded ground motions at the base of instrumented buildings in most cases are significantly lower than design earthquake (DE) ground motions. Because ASCE 7 is meant to provide demands at a DE level, for a more reliable evaluation of the F_p equation, 2 representative archetype buildings are designed based on the ASCE 7‐16 seismic provisions and exposed to various ground motion intensity levels (including those consistent with the ones experienced by instrumented buildings and the DE). Simulation results of the archetype buildings, consistent with previous numerical studies, illustrate the tendency of the ASCE 7 in‐structure amplification factor, [1 + 2(z/h)] , to significantly overestimate demands at all floor levels and the ASCE 7 limit of to in many cases underestimate the calculated NSC amplification factors. Furthermore, the product of these 2 amplification factors (that represents the normalized peak NSC acceleration) in some cases exceeds the ASCE 7 equation by a factor up to 1.50.  相似文献   

考虑地形起伏和障碍体破裂的汶川地震强地面运动数值模拟   总被引：2，自引：1，他引：1       下载免费PDF全文

赵由佳  张国宏  单新建  尹昊  屈春燕 《地球物理学报》2018,61(5):1853-1862

2008年5月12日四川汶川地区发生M_W7.9地震,震中位置103.4°E,31.06°N.这次地震造成了以汶川、映秀为中心及其周边地域建筑物的严重破坏和人员的重大伤亡,且因为高山等地形复杂区域抢险救灾的艰巨性,为及时救援造成很大干扰.为更好理解地形因素对于强地面数值模拟结果的影响,建立了包含地形起伏影响及去除地形影响的两类模型.同时,依据震源破裂过程运动学反演结果,建立了包含障碍体破裂过程的震源滑动模型,实现断层分段、空间倾角以及滑移角的动态设定.基于动力学的地震动模拟方法,通过对地震波传播过程的数值计算和后处理分析,模拟由地震激发的区域强地面运动过程.结果显示：（1）强震动台站的断层距对地形效应具有放大或抑制作用,距离断层破裂带越近,地形效应越明显,反之,距离越远,则地形效应越微弱;（2）因为地形高差与障碍体的影响,地震造成的峰值可能出现在震中区域之外;（3）考虑地形影响模型的地表峰值速度（PGV）区域位于汶川与北川附近;而未考虑地形影响模型的PGV区域位于灌县—江油断层的后半段,处清平、安县附近;对汶川地震近实时强地面运动波场的模拟、峰值图谱的圈定及未来大地震强地面运动特征的预测都有重要指示意义.  相似文献   

The formation of an anabranching planform in a sandy floodplain by increased flows and sediment load          下载免费PDF全文

Marcin Słowik 《地球表面变化过程与地形》2018,43(3):623-638

Anabranching rivers evolve in various geomorphic settings and various river planforms are present within these multi‐channel systems. In some cases, anabranches develop meandering patterns. Such river courses existed in Europe prior to intensive hydro‐technical works carried out during the last 250 years. Proglacial stream valleys, inherited from the last glaciation, provided a suitable environment for the development of anabranching rivers (wide valleys floors with abundant sand deposits). The main objective of the present study is to reconstruct the formation of an anabranching river planform characterized by meandering anabranches. Based on geophysical and geological data obtained from field research and a reconstruction of palaeodischarges, a model of the evolution of an anabranching river formed in a sandy floodplain is proposed. It is demonstrated that such a river system evolves from a meandering to an anabranching planform in periods of high flows that contribute to the formation of crevasse splays. The splay channels evolve then into new meandering flow paths that form ‘second‐order’ crevasses, avulsions and cutoffs. The efficiency of the flow is maintained by the formation of cutoffs and avulsions preventing the development of high sinuosity channels, and redirecting the flow to newly formed channels during maximum flow events. A comparison with other anabranching systems revealed that increased discharges and sediment loads are capable of forming anabranching planforms both in dryland and temperate climate zones. The sediment type available for transport, often inherited from older sedimentary environments, is an important variable determining whether the channel planform is anabranching, with actively migrating channels, or anastomosing, with stable, straight or sinuous branches. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Spatial coherency analysis of seismic ground motions from a rock site dense array implemented during the Kefalonia 2014 aftershock sequence          下载免费PDF全文

A. Svay  V. Perron  A. Imtiaz  I. Zentner  R. Cottereau  D. Clouteau  P.‐Y. Bard  F. Hollender  F. Lopez‐Caballero 《地震工程与结构动力学》2017,46(12):1895-1917

The objective of studies presented in this paper is to analyse the spatial incoherency of seismic ground motions using signals from a velocimeter dense array located on a rock site, recording the aftershock sequence of the two M6 Kefalonia earthquakes that occurred in January/February 2014 (Kefalonia island, Greece). The analyses are carried out with both horizontal and vertical components of velocigrams for small separation distances of stations (<100 m). The coherencies of seismic ground motions identified from strong motion windows are compared with those identified from coda parts of signals. It is realized that there is no significant difference between the coherencies estimated from those two parts of signals. The influence of earthquake event number on the result of coherencies and the dispersions of coherencies estimated from different earthquake events are presented. Finally, coherencies estimated from the dense array are compared with several coherency models proposed and widely used in the literature. The possibility of modifying some parameters of those existing coherency models to fit with in situ coherencies are discussed and presented. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

高烈度区公路隧道横通道地震响应分析          下载免费PDF全文

张楠  严松宏    刘子阳 《世界地震工程》2019,35(3):198-203

双洞隧道主隧道与横通道交接部位是隧道抗震中的薄弱位置,以穿越高烈度区隧道为背景,采用MIDAS GTS-NX有限元分析软件,对在汶川地震动作用下的公路隧道横通道进行地震响应分析。在X方向和Y方向地震动荷载的共同作用下,通过对围岩和衬砌的计算结果研究,得出以下结论:隧道整体的最大相对位移主要发生在主隧道与横通道拱顶和连接处;衬砌相对位移随埋深增加而减小;隧道产生的横向变形更大;横通道边墙位置更容易受到剪切破坏,主隧道与横通道连接处拱脚的弯矩、剪力、最大主应力和最大剪应力最大,应重点采取设防措施。  相似文献   

Dynamic loading tests and seismic response analysis of a stud-type damper composed of multiple friction units with disc springs     

Takeshi Sano  Kazutaka Shirai  Yasumasa Suzui  Yoshikazu Utsumi 《地震工程与结构动力学》2020,49(13):1259-1280

This paper presents an experimental study on the performance of a shear-sliding stud-type damper composed of multiple friction units with high-tension bolts and disc springs. A numerical evaluation of the response reduction effects achieved by the stud-type damper is also presented. In dynamic loading tests, the behavior of stud-type multiunit friction damper specimens was investigated. Three different full-scale damper specimens, which were composed of five, six, or seven friction units with two or four sliding surfaces, were incorporated into loading devices for testing. The stud-type friction dampers demonstrated stable rigid-plastic hysteresis loops without any remarkable decrease in the sliding force even when subjected to repetitive loading, in addition to showing no unstable behavior such as lateral buckling. The damper produced a total sliding force approximately proportional to the number of sliding surfaces and friction units. The total sliding force of the stud-type damper can thus be estimated by summing the contributions of each friction unit. In an earthquake response simulation, the control effects achieved by stud-type dampers incorporated into an analytical high-rise building model under various input waves, including long-period, long-duration and pulse-like ground motions, were evaluated. A satisfactory response reduction was obtained by installing the developed stud-type dampers into the main frame without negatively impacting usability and convenience in terms of building planning.  相似文献