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1.
针对钢筋混凝土高层建筑抗震时程分析输入地震波选择问题,以《建筑抗震设计规范》(GB 50011-2016)设计谱为目标谱,将满足谱匹配原则的加权调幅选波方法与国内学者建议的其它输入地震波选择方法进行了对比研究。以3栋钢筋混凝土高层建筑(15层、30层和44层)为实例,针对8度罕遇地震作用和Ⅱ类场地条件,将上述方法建议的各7条地震波输入结构进行弹塑性时程分析。以结构最大层间位移角均值沿楼层分布为比较参数。结果表明:加权调幅法可用于钢筋混凝土高层建筑抗震时程分析,可以较好地降低结构地震反应均值的离散性。在8度罕遇地震作用条件下,以不同学者建议选择的地震波为输入,高层建筑时程分析结果仍呈现出较大的不同。  相似文献   

2.
分别采用基于塑性铰法的空间梁柱单元分析程序和简化的DRAIN-20分析程序,对其主体巨型钢框架结构进行了考虑双重非线性的罕遇地震作用下的时程反应分析。分析中使用了三条典型地震波和一条当地人工地震波,分别得到了顶层位移和加速度时程曲线、层间位移包络值和塑性铰出现的位置与先后顺序。分析结果表明结构在体系设计上是合理的和在大震作用下具有足够的安全度。  相似文献   

3.
本文以某异型钢管混凝土拱桥为研究对象,通过ANSYS建立了结构的空间有限元模型,计算和分析了该桥的动力特性。同时,通过MATLAB程序生成拟合规范反应谱的人工地震波,并运用时程分析法计算了该桥在一维和多维输入下的地震反应,分析了该桥的地震反应规律,为钢管混凝土拱桥的抗震性能分析提供了一定的依据。  相似文献   

4.
以实际工程为依托,采用有限元软件ANSYS对钢筋混凝土圆筒仓仓壁结构进行数值模拟。通过模态分析,得到了筒仓结构的自振频率和周期。在模态分析的基础上,采用时程分析法,输入TAFT地震波,对模型结构进行动力有限元分析,得出结构在地震作用下的顶点位移时程曲线,找出最大位移发生时刻,并绘制该时刻结构的整体应力、变形图。最后,考虑不同贮料工况,对结构在TAFT地震波作用下进行了地震反应分析,得到相应的结论,为同类结构的抗震设计提供理论依据。  相似文献   

5.
为了研究随机地震动场多点激励作用下宽幅大跨桥梁结构的地震响应,基于二维相干模型,考虑地震波非平稳性合成桥址各支承点的人工地震加速度时程波,采用多项式拟合法在时域内对各支承点处的人工合成加速度波进行校正,并对校正前后加速度波的响应谱进行比较校验;随后以某大跨自锚式悬索桥为例,利有限元软件中线性时程分析模块,将所合成的加速度地震波施加于结构,对比研究一致激励与随机地震动多点激励下宽幅大跨桥梁结构的地震响应。分析表明,考虑二维相干和地震波非平稳性合成的各支承点地震加速度时程波可采用多项式拟合法进行基线漂移现象的校正,同时应对修正前后加速度波的反应谱进行比较校验;对于大跨且横桥向支承点相距较远的桥梁结构应考虑横桥向地震波的非一致性。  相似文献   

6.
建立在地震作用下设置阻尼器的基础隔震结构在最大地震响应时刻的能量平衡方程,给出了结构隔震支座和阻尼器的能量表达式,演算了基于能量平衡的设置阻尼器的基础隔震结构的地震响应预测式.选用人工地震波和天然地震波,利用时程分析法的解析值验证了地震响应预测式的精度,比较研究了仅设置粘性阻尼器和同时设置粘性阻尼器和滞回阻尼器的基础隔震结构的抗震性能.研究表明:对于不同的输入地震波,能量法的地震响应预测值包络了多数时程分析的结果,能较好地预测基础隔震结构的地震响应值.在基础隔震结构设计中,建议在隔震层同时设置粘性阻尼器和滞回阻尼器,粘性阻尼器的阻尼比在0.3 ~0.4之间.  相似文献   

7.
选择合适的人造地震动时程是高层建筑采用时程分析法计算地震作用的基础。介绍了徕远广场结构设计地震波的确定方法及过程。鉴于各条地震波输入进行时程分析的结果的离散性,提出可以采用场地土层反应分析得到的地表加速度时程及按照《高层技术规程》设计规准谱拟合人造波作为结构设计地震波。  相似文献   

8.
地震波输入对结构非线性响应具有重要影响,选取合适的地震波输入计算是保证结构时程分析响应结果准确的首要条件。文章通过对比地震波瞬时谱的模型化方法,优化并提出可以考虑地震波时频特性的选波方法,并与《建筑抗震设计规范》方法进行对比分析。结果表明:匹配瞬时谱的选波方法可以有效地控制所选地震波的时、频域差异性,降低结构时程分析响应离散度,可为工程选波提供依据。  相似文献   

9.
动力分析过程中输入地震波的选择非常重要,通过扰动自然波生成人工地震波是丰富设计地震波池的方法之一。提出使用复连续小波变换来修改、扰动自然波的方法来拟合人工地震波,以2000年日本鸟取M_W6.7地震为研究对象,对比Shannon小波基和Gabor小波基在生成人工波过程中的特点。结果表明:使用改进方法可以在任意指定的时-频域上修改地震波的相位谱从而产生人工波,且Shannon小波对地震波能量的保留优于Gabor小波,故Shannon小波基是更好的选择。  相似文献   

10.
陈帆  石卫华 《华南地震》2004,24(4):46-49
以单层柱面网壳结构为研究对象,利用El-centro地震波对该类结构进行了时程地震反应分析,考察了结构的地震响应和抗震性能,研究了其在地震作用下的动力失稳特点。选取了几种几何尺寸不同的单层柱面网壳,分析了矢跨比和长跨比对单层柱面网壳动力稳定性能的影响。  相似文献   

11.
1989年10月18日22时58分在山西省大同县东南发生了Ms6.0地震,之后余震不断。为了现场震情监视,地震发展趋势,强余震预报等研究工作的需要,对其主余震参数进行了较为精确的测定,并计算得到直达波P的速度为5.93km/s,虚波速度为7.99km/s,地震多集中发生在深度为10-15km地段。  相似文献   

12.
Abstract

The time of concentration is a primary parameter for a variety of modern hydrological models adopted in professional and scientific communities. Nevertheless, a universally accepted working definition of this parameter is currently lacking and several definitions can be found in the technical literature along with related estimation procedures. This study brings to light the inherent variability of these definitions through the empirical analysis of four small basins. These case studies demonstrate that available approaches for the estimation of the time of concentration may yield numerical predictions that differ from each other by up to 500%.

Editor D. Koutsoyiannis

Citation Grimaldi, S., Petroselli, A., Tauro, F. and Porfiri, M., 2012. Time of concentration: a paradox in modern hydrology. Hydrological Sciences Journal, 57 (2), 217–228.  相似文献   

13.
Abstract

Large errors in peak discharge estimates at catchment scales can be ascribed to errors in the estimation of catchment response time. The time parameters most frequently used to express catchment response time are the time of concentration (TC), lag time (TL) and time to peak (TP). This paper presents a review of the time parameter estimation methods used internationally, with selected comparisons in medium and large catchments in the C5 secondary drainage region in South Africa. The comparison of different time parameter estimation methods with recommended methods used in South Africa confirmed that the application of empirical methods, with no local correction factors, beyond their original developmental regions, must be avoided. The TC is recognized as the most frequently used time parameter, followed by TL. In acknowledging this, as well as the basic assumptions of the approximations TL = 0.6TC and TCTP, along with the similarity between the definitions of the TP and the conceptual TC, it was evident that the latter two time parameters should be further investigated to develop an alternative approach to estimate representative response times that result in improved estimates of peak discharge at these catchment scales.
Editor Z.W. Kundzewicz; Associate editor Qiang Zhang  相似文献   

14.
选取大同地震台记录的2010—2019年531个MS≥5.0地震事件,根据发震区域的不同对其波形走时残差进行分析,得到不同发震区域地震波形的平均走时残差。结果表明,日本、喜马拉雅地区地震波形的走时残差总体为负值,平均残差分别为-1.51 s、-0.70 s;斐济、中国台湾地区、南美洲西海岸地区大多为正值,平均残差为0.79 s、1.83 s、1.86 s。同时发现,在有干扰的情况下参考不同区域平均走时残差计算结果,通过判断实际初至震相与理论初至震相的位置关系,可以更好地开展初至波震相识别工作。  相似文献   

15.
Transport time scales are key parameters for understanding the hydrodynamic and biochemical processes within estuaries. In this study, the flushing and residence times within the Arvand River estuary have been estimated using a two‐dimensional hydrodynamic model called CE‐QUAL‐W2. The model has been calibrated and verified by two different sets of field data and using the k‐ε vertical eddy diffusivity scheme. Flushing time has been estimated using different methods such as the tidal prism and fraction of freshwater methods. Moreover, residence times have been investigated using pulse residence time, estuarine residence time and remnant function approaches. The results have shown that different methods yield different time scales, and freshwater inflow has the greatest impact upon estimation of residence time, whereas tidal circulation hardly contributes to residence time at all. It has also been shown that the neap‐spring circulation and start phase of simulations have negligible effects on the Arvand's time scales. The investigation of bathymetry showed that two sills of the estuary tend to significantly increase residence time. Understanding the applicability of these time scales and their estimation approaches helps us to evaluate the water quality management of estuaries. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
从地震活动间隔时间和等待时间的角度出发,结合1970~2003年华北地区的地震活动,对其5 0级以上地震、5 4级以上地震和6 0级以上地震活动的等待时间特征进行了分析,并给出了地震活动次数百分比随等待时间变化的等值线特征,最后简略地介绍了历史地震活动的一些特征。  相似文献   

17.
This paper deals with the distributive characteristics of the occurrence time of earthquakes with respect to the aftershock sequences of strong earthquakes. The distribution of lunar and solar local hour angles at the time of commencement of moderate and strong aftershocks indicates that the time of commencement of moderate and strong aftershocks is modulated by the positions of the sun and moon and then the earthquake-restrained time zones exists also. In this paper the differences of earthquake-restrained time zones between the preshock sequences and the aftershock sequences are compared, and the possible mechanism is analyzed preliminarily. And the possible maximum scope of accuracy in predicting the occurrence time of an earthquake is determined as well. This paper is supported by the Eight Five Year Target of the State Seismological Bureau, China.  相似文献   

18.
This paper presents the implementation details of a real‐time pseudodynamic test system that adopts an implicit time integration scheme. The basic configuration of the system is presented. Physical tests were conducted to evaluate the performance of the system and validate a theoretical system model that incorporates the dynamics and nonlinearity of a test structure and servo‐hydraulic actuators, control algorithm, actuator delay compensation methods, and the flexibility of an actuator reaction system. The robustness and accuracy of the computational scheme under displacement control errors and severe structural softening are examined with numerical simulations using the model. Different delay compensation schemes have been implemented and compared. One of the schemes also compensates for the deformation of an actuator reaction system. It has been shown that the test method is able to attain a good performance in terms of numerical stability and accuracy. However, it has been shown that test results obtained with this method can underestimate the inelastic displacement drift when severe strain softening develops in a test structure. This can be attributed to the fact that the numerical damping effect introduced by convergence errors becomes more significant as a structure softens. In a real‐time test, a significant portion of the convergence errors is caused by the time delay in actuator response. Hence, a softening structure demands higher precision in displacement control. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

19.
针对目前地震前兆设备存在较大时钟偏差及时钟不一致的问题,分析了存在问题的关键环节,并给出了一套在地震行业网三级结构的节点分别部署校时钟服务器的方案.由国家中心时钟源同步区域中心时钟源、区域中心时钟源同步所辖台站时钟源,最终实现前兆设备在台站内部校时.通过此方案,设备校时可在本地完成,减少了网络中断、延时的影响;均衡国家中心网络校时服务器的负载,可以基本解决全国前兆设备时钟偏差较大和不一致的问题.   相似文献   

20.
We present a comparison of methods for the analysis of the numerical substructure in a real‐time hybrid test. A multi‐tasking strategy is described, which satisfies the various control and numerical requirements. Within this strategy a variety of explicit and implicit time‐integration algorithms have been evaluated. Fully implicit schemes can be used in fast hybrid testing via a digital sub‐step feedback technique, but it is shown that this approach requires a large amount of computation at each sub‐step, making real‐time execution difficult for all but the simplest models. In cases where the numerical substructure poses no harsh stability condition, it is shown that the Newmark explicit method offers advantages of speed and accuracy. Where the stability limit of an explicit method cannot be met, one of the several alternatives may be used, such as Chang's modified Newmark scheme or the α‐operator splitting method. Appropriate methods of actuator delay compensation are also discussed. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

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