矩形高层建筑扭转动力风荷载解析模型

本文通过研究不同长宽比、高宽比的矩形棱柱体在边界层风洞中典型攻角下的扭矩，提出了矩形高层建筑扭矩功率谱密度、均方根扭矩系数和Strouhal数的经验公式，并对相干函数作了一定的探讨，建立了完整的扭转动力风荷载解析模型。该模型和试验结果吻合较好，证明它是合理有效的，可在此基础上建立高层建筑扭转动力响应频域计算方法。     

两结构高效阻尼控制体系试验研究

本文通过模拟地震动振动台试验，研究了两个相邻结构模型的地震响应，结构模型采用一种高效阻尼装置(High Efficient Damper for Multi—Structure System即HEDMS)连接。非线性时程分析与振动台试验结果都证明了该阻尼装置能高效发挥软钢阻尼器的耗能能力，从而显著减轻两结构模型的地震响应。同时，研究还指出了进行阻尼装置设计时应该注意的一些问题。     

煤层上覆地层含水不均匀性电法探测的可能性

煤田上覆岩层中含水直接对煤层的开采构成威胁，本文先从理论上阐述了电阻率勘探可以探测煤层上覆地层含水不均匀性的可能性，然后用简单的断层型薄层含水模型的CSAMT正演模拟结果展示出：地下900m深处，尽管只有20m厚的的含水岩层，但在电阻率剖面上该薄层的反映具有非常明显的特征，从理论上和数值模拟实例说明，一定深度内一定厚度的薄层含水性的电阻率法探测是可能的。     

Method of high-density seismic imaging ex-ploration and application samples

Introduction Now, shallow seismic reflection wave technique has been used extensively in geological ex-plorations of bridge, dam, high building and so on. Since shallow seismic reflection wave tech-nique is often implemented in industrial zone or city with dense population, the background dis-turbance including industrial noise, life noise, etc is very serious. Furthermore, the disturbance of seismic source is also serious due to short array length and offset of the method. In general, shal-lo…     

Period formulas of shear wall buildings with flexible bases

The evaluation of the fundamental period of shear wall buildings considering the flexibility of the base is investigated in this paper. This research is motivated by the discrepancy reported between the formulas used in different building codes and the measurement of real buildings. Both experimental and analytical approaches are used to assess the effect of the base flexibility on the fundamental period of shear wall structures. In total, twenty buildings built on different types of soil are tested under ambient vibration. The fundamental period is identified using a non‐parametric linear model in the frequency domain. The results show that fundamental period formulas used by UBC‐97 and NBCC‐95 are inadequate since they do not include the effect of the foundation stiffness. To improve the estimation of the fundamental period of shear wall buildings, an analytical approach is presented. The structure and the foundation are represented by a continuous‐discrete system. The stiffnesses of the base are represented by translational and rotational discrete springs. The rigidities of these springs are evaluated from the elastic uniform compression of the soil mass and the size of the foundation. The analytical predictions improve the estimation of the fundamental period and keep the computation simple. The error between the measured period and the analytical results is, on average, less than 10%. Copyright © 2003 John Wiley & Sons, Ltd.     

Approximate modal decomposition of inelastic dynamic responses of wall buildings

Two approximate methods for decomposing complicated inelastic dynamic responses of wall buildings into simple modal responses are presented. Both methods are based on the equivalent linear concept, where a non‐linear structure is represented by a set of equivalent linear models. One linear model is used for representing only one vibration mode of the non‐linear structure, and its equivalent linear parameters are identified from the inelastic response time histories by using a numerical optimizer. Several theoretical relations essential for the modal decomposition are derived under the framework of complex modal analysis. Various numerical examinations have been carried out to check the validity of the proposed modal decomposition methods, and the results are quite satisfactory in all cases. Fluctuating bending moment and shear at any location along the wall height contributed by each individual vibration mode can be obtained. Modal contributions to shear and flexural strength demands, as well as the corresponding modal properties, under various seismic loading conditions can also be identified and examined in detail. Furthermore, the effects of higher vibration modes on seismic demands of wall buildings are investigated by using the modal decomposition methods. Several new insights into the complicated inelastic dynamics of multi‐story wall buildings are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

剔除高密度电阻率法三极装置浅部不均匀体效应影响的方法及效果

基于总结出的高密度电阻率法三极测量装置下的二维正演拟断面中浅部不均匀体畸变规律和特征,设计了一套能有效剔除三极测量装置浅部不均匀体效应影响的数据处理方法,成功应用于野外实测数据的处理。     

Proposal of a National Mitigation Strategy Against Earthquakes in Turkey

While laboratory and analytical studies can provide valuable information about earthquake hazard mitigation, the most effective educator is the impact of a full-scale earthquake on a full-scale city. The recent earthquakes in Turkey showed that the governmental as well as individual attitudes towards earthquakes did not represent proportionate responses to the risk levels concerned. Turkey had weaknesses in preparing, planning, mitigating and responding to disasters in spite of the known seismic vulnerability of the country. Many steps have been taken after 1999 earthquakes in Turkey, however, the preparations largely concentrate on the response and recovery phases and a fundamental step to reform the current disaster management system and steps to rehabilitate the vulnerable building stock has not been undertaken until today. This would involve changing the present laws and regulations and de-centralising the disaster management system. The aim of this paper is to propose a national mitigation strategy for Turkey for a time-frame of 10 years. The model proposed is a very comprehensive model for earthquake risk reduction in Turkey and within this context, the legislative and technical aspects of mitigation will be discussed in detail. Strategies for mitigating and retrofitting the existing building stock will also be proposed.     

Studies on wind environment around high buildings in urban areas

High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in Beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings.     

高建筑对周围建筑雷击保护距离的模拟

在已有先导连接参数化方案的基础上,选取近地面层为研究区域,保持方案中其他基本参量不变,通过改变闪电的空间形态,在同一建筑分布的背景下进行多次闪电模拟。研究多个建筑之间的屏蔽作用以及建筑雷击保护距离与建筑相关特征参数之间的关系,结果表明:高建筑对矮建筑具有屏蔽作用,并存在一个临界保护距离,当高、矮建筑高度分别为190 m和165 m,宽度均为20 m时,建筑之间的距离在12 m以内,矮建筑受高建筑完全保护不遭受雷击;建筑之间的距离超过12 m,矮建筑遭雷击次数明显增多。