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21.
桥梁限位器抗震设计方法研究   总被引:4,自引:0,他引:4  
本文建立了两跨简支梁桥和五跨多跨刚架桥两结构模型,针对限位器的种类、刚度、强度、安装位置,输入地震动等进行了大量工况下的数值模拟研究。研究表明限位器与柱(框架)的刚度比在0.5-2之间较优。将现有的限位器设计方法应用于两算例结构,对现有限位器设计方法进行了比较研究。  相似文献   
22.
提出依据开挖剖面中的楔形体在受到断层作用时其厚度的变化量求解断层水平位移的方法。分析表明断层水平位移量S与楔形体在断层两侧厚度变化量Δh满足关系式S=Δh/ρsinβ。式中ρ为楔形体在断层走向上的尖灭系数,β为断层的倾角,该关系式不仅能满足纯走滑运动的断层,而且也满足一般斜滑断层,同时提出了在剖面上判断断层水平运动性质的方法。  相似文献   
23.
Introduction The development and application of Interferometric Synthetic Aperture Radar (InSAR) have a close relationship with the sensors development of Synthetic Aperture Radar (SAR). The conception of SAR is proposed comparatively to the real aperture radar antenna. It is well known that the longer the antenna is, the higher the observation resolution will be. Just limited by the length of the antenna, the resolution of real aperture radar is generally very low and cannot meet the r…  相似文献   
24.
The Building Standard Law of Japan and related Enforcement Order and Notifications have been substantially revised since the year 2000 to introduce a performance-based regulatory and deregulation system for building control systems. Up to then, time-history analyses were mandatory for isolated buildings and had to be specially approved by the Minster of the Ministry of Construction (MOC). Simplified design procedures based on the equivalent linear method for seismically isolated buildings have been issued as “Notification 2009 — Structural calculation procedure for buildings with seismic isolation” from MOC, and are now integrated into the Ministry of Land, Infrastructure, and Transportation (MLIT). Along with Notification 2009, “Notification 1446 of year 2000 — Standard for specifications and test methods for seismic isolation devices” was also issued. Buildings with heights equal to or less than 60m and that are designed according to these Notifications, including base isolated buildings, only need approval from local building officials, and no longer require the special approval of the Minister of MLIT. This paper summarizes: 1) some statistics related to buildings with seismic isolation completed up to the end of 2001; 2) simplified design procedures required by Notification 2009 of year 2000; and 3) performance of seismic isolation devices required by Notification 1446 of year 2000.  相似文献   
25.
位移监测在滑坡时空运动研究中的应用   总被引:5,自引:0,他引:5  
滑坡时空运动特征是滑坡地质体在内因和外因共同作用下,自一种状态向另一种状态转化的地质过程。滑坡位移监测是研究滑坡变形影响因素、动态规律及预测预报的主要途径,特别是滑坡深部位移监测,又为研究滑坡体的时空运动过程提供了重要信息。本文结合几个滑坡的深部位移监测实践,综合分析位移监测信息,研究滑坡体的时空运动特征及发展趋势,为滑坡时空运动系统研究及稳定性预测提供依据。  相似文献   
26.
First, central to our analysis is the argument that human movement within and across borders fundamentally challenges the view of geopolitics based upon fixed territorial states, inter-state relations, national identities and citizenship; indeed the whole idea of "national geographic". Using the examples of the Karen and Shan peoples, we explore the processes and patterns of forced relocation, displacement and migration in the border regions of Myanmar and Thailand. Our main concern is with forced displacement as a result of political and ethnic conflict; specifically, how the Burmese military regime's desire for "national unity" within Myanmar's "national space" has influenced the militarily inspired displacements of hundreds of thousands of villagers and civilians within the border zones inhabited mostly by so-called "national minorities". We examine the particular problems of the so-called "internally displaced persons" within "national" boundaries compared with the "refugees" and "undocumented migrants" who make it across "international" space into Thailand. We illustrate the ways displaced people are represented by state agencies and the media as "threats" and "transgressors". We consider some of the "long term" aspects of the displacement problem along the Myanmar-Thai border and the vital contribution geographers can make to the study of displacement.  相似文献   
27.
28.
医院住院部大楼抗震性能评价   总被引:1,自引:0,他引:1  
以某医院住院部大楼为例进行结构抗震性能评价,首先分析了场址的地震环境,开展了地震危险性分析工作,合成了不同地震危险水平下的地震动加速度时程。进而,通过对结构的模型简化,应用时程分析方法分析结构的抗震性能,得出了一些对其改造加固有意义的结论。  相似文献   
29.
Introduction The rock medium shows mainly elastic character under low-temperature, low-pressure and external force for short duration, yet it shows rheologic property under high-temperature, high-pressure and long-time external force. It is reasonable that the rapid earthquake generating process lasted for tens seconds is analyzed by the elastic theory. As for the earthquake generating process for hundreds or thousand years, nevertheless, the rheologic property of rock must be taken into accou…  相似文献   
30.
Results of a detailed statistical study of constant relative strength inelastic displacement ratios to estimate maximum lateral inelastic displacement demands on existing structures from maximum lateral elastic displacement demands are presented. These ratios were computed for single‐degree‐of‐freedom systems with different levels of lateral strength normalized to the strength required to remain elastic when subjected to a relatively large ensemble of recorded earthquake ground motions. Three groups of soil conditions with shear wave velocities higher than 180m/s are considered. The influence of period of vibration, level of lateral yielding strength, site conditions, earthquake magnitude, distance to the source, and strain‐hardening ratio are evaluated and discussed. Mean inelastic displacement ratios and those associated with various percentiles are presented. A special emphasis is given to the dispersion of these ratios. It is concluded that distance to the source has a negligible influence on constant relative strength inelastic displacement ratios. However, for periods smaller than 1s earthquake magnitude and soil conditions have a moderate influence on these ratios. Strain hardening decreases maximum inelastic displacement at a fairly constant rate depending on the level of relative strength for periods of vibration longer than about 1.0s while it decreases maximum inelastic displacement non‐linearly as the period of vibration shortens and as the relative‐strength ratio increases for periods of vibration shorter than 1.0s. Finally, results from non‐linear regression analyses are presented that provide a simplified expression to be used to approximate mean inelastic displacement ratios during the evaluation of existing structures built on firm sites. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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