Inelastic buildings with tuned mass dampers under moderate ground motions from distant earthquakes

The effectiveness of tuned mass dampers (TMD) in vibration control of buildings was investigated under moderate ground shaking caused by long‐distance earthquakes with frequency contents resembling the 1985 Mexico City (SCT) or the 1995 Bangkok ground motion. The elastic–perfectly plastic material behaviour was assumed for the main structure, with linear TMDs employed by virtue of their simplicity and robustness. The accumulated hysteretic energy dissipation affected by TMD was examined, and the ratio of the hysteretic energy absorption in the structure with TMD to that without it is proposed to be used, in conjunction with the peak displacement ratio, as a supplementary TMD performance index since it gives an indication of the accumulated damage induced in the inelastic structures. For the ground motions considered, TMD would be effective in reducing the hysteretic energy absorption demand in the critical storeys for buildings in the 1.8–2.8 s range. The consequence is reduction in damage of the buildings which would otherwise suffer heavy damage in the absence of TMD, resulting in economical restorability in the damage control limit state. This is of practical significance in view of the current trend toward performance‐based design. Copyright © 2001 John Wiley & Sons, Ltd.     

Effect of earthquake ground motions on fragility curves of highway bridge piers based on numerical simulation

Fragility curves express the probability of structural damage due to earthquakes as a function of ground motion indices, e.g., PGA, PGV. Based on the actual damage data of highway bridges from the 1995 Hyogoken‐Nanbu (Kobe) earthquake, a set of empirical fragility curves was constructed. However, the type of structure, structural performance (static and dynamic) and variation of input ground motion were not considered to construct the empirical fragility curves. In this study, an analytical approach was adopted to construct fragility curves for highway bridge piers of specific bridges. A typical bridge structure was considered and its piers were designed according to the seismic design codes in Japan. Using the strong motion records from Japan and the United States, non‐linear dynamic response analyses were performed, and the damage indices for the bridge piers were obtained. Using the damage indices and ground motion indices, fragility curves for the bridge piers were constructed assuming a lognormal distribution. The analytical fragility curves were compared with the empirical ones. The proposed approach may be used in constructing the fragility curves for highway bridge structures. Copyright © 2001 John Wiley & Sons, Ltd.     

春季急行冷锋结构之分析

台湾地区冬末春初间偶有急行冷锋通过，带来雷雨及强风，甚至降雹，对农业造成不小的损失，深值我气象人员注意，作者就１９９２年４月１９日上午通过台湾省中南部地区的急行岭锋，利用雷达资料分析其垂直结构和水平结构。     

古田溪一级大坝变形观测系统改造及自动化设计

本文介绍了古田汉一级大坝原有变形观测项目及存在的主要问题，提出了观测系统改造的原则和要求。详细论述了各观测项目增设、改造及自动化设计的实施方案，给出了相应的精度估算。     

秦山核电站厂址地震动加速度时程预测研究

本文研究了建立设计地震震源模型和用理论地震学方法预测基岩场地震震加速度的技术途径，预测了四相设计地震事件在秦山核电站厂址的加速度时程和反应谱，文中根据对地质和历史地震资料的研究，确定不同性质的设计地震事件，建立设计地震震源和工作区介质的确定性模型，针对未来地震的不可完全预见性，以及对地球介质和震源性质现有认识的局限性，文中发展了确定性和随机性组合的综合分析方法，在用确定的介质模型和设计震源计算地震     

Rocking response of flexible circular foundations on layered media

The analysis of the response of a flexible circular foundation on layered media due to an arbitrarily distributed vertical loading is presented. The analysis is based on the ‘ring method’ approach, i.e. discretization of the foundation in a set of concentric rings. The arbitrarily distributed loading is expanded in the circumferential direction in a Fourier series. The influence coefficient matrix of soil for each element of the series is evaluated utilizing the stiffness matrix approach. The stiffness matrix of the foundation is obtained from the finite difference energy method approach. Numerical examples illustrate the influence of several soil-foundation parameters on the rocking response of a foundation. Results are presented in terms of displacement and soil reaction distributions and impedance functions point to significantly different responses of flexible and rigid foundations.     

逐步带逼近法在热带所旋路径预报中的应用

通过对逐步逼近法１９９５年试验情况与国内外预报台的综合预报以及与国内一些客观预报方法的比较分析，总结出该方法对移动路径明显转折的热带气旋有较好的预报能力，４８小时平均误差达到３００ｋｍ以内，特别是当热带气旋的移速发生明显变化时，该方法较之其它客观方法有明显的优越性。     

青藏块体北缘跨断层测量资料宏观分析

本文在系统整理青藏块体北缘跨断层测量资料的基础上，进行了形变类型的划分，探讨了不同类型形变所反映的断层运动性能。     

关于垂直分量磁变仪的灵敏度问题

目前国内地磁台垂直分量磁变以的灵敏度都普遍偏低，不能适应一些研究工作的需要，必须予以适当的提高，本文在基本不改变仪器固有灵敏度的前提下，采取记录光线二次反射法，以提高仪器的记录灵敏度，利用这种方法既使仪器的灵敏度提高一倍同时又保证了仪器原有的稳定性。     

The effect of local irregular topography on seismic ground motion

Ｔｈｅｅｆｆｅｃｔｏｆｌｏｃａｌｉｒｒｅｇｕｌａｒｔｏｐｏｇｒａｐｈｙｏｎｓｅｉｓｍｉｃ　ｇｒｏｕｎｄ　ｍｏｔｉｏｎＪＩＧ－ｈｏＬＩＵ（刘晶波）（ＤｅｐａｒｔｍｅｎｔｏｆＣｉｖｉｌＥｎｇｉｎｅｅｒｉｎｇ，ＴｓｉｎｇｈｕａＵｎｉｖｅｒｓｉｔｙＢｅｉｊｉ...