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61.
《Mauerwerk》2018,22(4):260-272
Brazilian structural concrete and clay block masonry construction shares many common features with construction all over the world: blocks of a similar shape are bedded in mortar, vertical and horizontal reinforcement is placed in grouted cells, engineering analysis and design follows universal principles and local design codes mimic those adopted elsewhere. However, loadbearing masonry construction in Brazil has become one of the most preferred high‐rise building systems due to its cost‐effectiveness and ease of construction compared to normal reinforced concrete solutions. This paper provides an overview of loadbearing masonry building in Brazil, including case studies on notable high‐rise masonry structures, with an overview of how Brazilian materials, codes and practices differ from the rest of the world. Finally, the paper explains how the use of high‐strength units assists the growing demand for taller and taller buildings and provides insight into why owners and general contractors often prefer to use structural masonry. 相似文献
62.
Due to the featured high-amplitude, long-period pulses in velocity or displacement time–history, the near-fault ground motion may have a stronger destructive effect on engineering structures. Therefore, studying velocity pulses modeling of near-fault ground motions has been an important topic in the earthquake engineering community. However, the variability and probabilistic correlation of pulse model parameters have not received enough attention. To this end, an elegant method for stochastic simulation of velocity pulses of near-fault ground motions is proposed based on the classical Gabor wavelet modeling and probabilistic correlation analysis of associated model parameters by multivariate copula modeling. Especially, an efficient scheme of iteratively determining the optimal copulas pertinent to edges of a complex vine structure is developed, and two parameters relevant to the near-fault ground motion records, i.e., the rupture distance and the strongest pulse orientation, are introduced which provides a physical basis for addressing the dependence structure among variables. For illustrative purposes, the ground accelerograms recorded by near-fault instruments in the 1999 Chi-Chi earthquake are used. It is shown that the multivariate copula modeling enables the efficient representation of probabilistic correlation between model parameters which is consistent with their physical mechanism. The time histories and spectral characteristics of velocity pulses of near-fault ground motions and their stochastic fluctuations with respect to the rupture distance are well simulated. While the empirical linear regression model does not meet the requirements of random vibration analysis and thus cannot guide the safety design of seismic structures. 相似文献
63.
针对中性点不接地系统单向接地电容电流易造成配电网络次生灾害和设备损害、易产生单向电弧接地过电压和铁磁谐振过电压的问题,分析评估了任楼煤矿电网电容电流的测试数据,根据评估结果制定了电容电流治理方案,即将中性点不接地系统改为中性点经消弧线圈接地运行方式,并给出了具体实施方案。运行结果表明,该方案大大减少了高幅值电弧接地过电压发生的几率,抑制了铁磁谐振过电压,有利于提高电缆寿命。 相似文献
64.
汪肇强 《数字社区&智能家居》2010,(5):1056-1057,1062
该文介绍了网络及其存储技术在地震数据管理中的作用,分析了地震数据存储面临的特点,并通过分析对比各存储结构及网络结构.设计了一个用于地震数据存储的网络存储方案。 相似文献
65.
采用有限元法对某超大型连续式跨声速风洞进行地震安全分析。使用ANSYS建立整体结构模型并施加实际约束,为确保计算精度和计算效率,采用实体壳单元SOLIDSHELL进行网格划分;依据JB/T 4710—2005《钢制塔式容器》和仿真模态分析进行水平地震力计算;基于JB 4732—1995《钢制压力容器——分析设计标准》对风洞进行强度评定。计算结果表明:在地震载荷作用下,该风洞主体结构强度安全裕量较大,其结构形式合理可靠。 相似文献
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68.
地震过程中,最大峰值加速度是一个随机量,不宜作为地震动特性的标志,因此,利用均方根加速度,计算相应的地震力,然后根据正弦函数曲线把地震力加载在不同土层的黄土边坡中.对黄土边坡在地震力作用下的安全性进行比较研究,为黄土边坡抗震设计提供参考依据. 相似文献
69.
“5·12”汶川地震后泥石流汇流区和流通区沟道内覆盖有巨厚的滑坡、崩塌等松散物质.松散物质在强降雨作用下容易启动形成泥石流.泥石流形成后通过时会侵蚀松散堆积物,与沟床存在动态的物质交换,其规模沿程不断扩大,而且运动阻力特性不同于一般定床情况.为定量分析动床条件下泥石流阻力和一次降雨引发泥石流的冲出总量,本文首先以灾区6条泥石流沟为研究对象,通过多元回归分析发现泥石流阻力与输沙量和弗罗德数存在良好的相关性,初步得到了泥石流动床阻力的估算方法.然后统计分析了北川和清平16条泥石流沟的基本数据,发现一次降雨引发泥石流的冲出总量与日降雨量和流域汇流面积存在较好的幂指数关系,得到了降雨控制型泥石流总量估算方法.研究结果对震后泥石流防灾减灾工程设计具有一定的参考价值. 相似文献
70.
Dynamic response law about gravity retaining wall to seismic characteristics and earth fill properties 总被引:1,自引:1,他引:0
In order to find the dynamic response laws of retaining walls affected by certain earthquake loads, the influence of the seismic
wave characteristics and sub-grade fill parameters (including the foundation surface slope) were focused on, and a series
of tests were performed. The results show that the maximum stress of the retaining wall decreases as internal friction angle,
foundation slope, filled soil cohesion and the biggest dynamic elastic modulus increase, while it increases with the seismic
frequency and seismic input peak dropping. The addition value of dynamics earth pressure increases when seismic frequency
and seismic input peak are reduced, while it decreases when the filled soil cohesion and internal friction angle rise. Meanwhile,
dynamic elastic modulus and foundation slope have no obvious influences on addition value of dynamics earth pressure. The
slope will be instable if the seismic input peak exceeds 0.5g and be disruptive if seismic frequency is larger than 2.5 Hz. The mid-lower parts of retaining walls are in most heavy and
obvious response to these factors, which reveals the mechanism of “belly burst” in retaining wall that appears commonly in
practical projects. 相似文献