芦山地震中校舍建筑的震害特点与分析

本文对芦山地震中的校舍建筑震害进行调查和分析.调查发现,汶川地震后重建的框架结构,由于按照新的抗震规范进行设防,大多数没有出现结构性损伤,震害集中在填充墙等非结构构件上.建于汶川地震前的框架结构,当不符合规范的强制条文时,破坏严重,特别是单跨框架,个别发生首层柱端破坏.砖混结构校舍中的宿舍楼,由于开间小,横墙多,多设置了构造措施,虽有结构破坏,但均可修复.砖混结构教学楼采用砖墙-框架柱混合承重的结构体系,大多在汶川地震后得到加固,未加固的教学楼有严重的结构破坏,而加固后的校舍建筑则表现较好,但是这些结构体系多采用预制空心板,整体性较差,已经被规范禁止用于校舍建筑.场地对结构震害有重要的影响,密实的持力层、妥善的地基处理和整体性好的基础形式,可以大幅度减轻结构的震害.本文建议:应加强校舍建筑基于性能设计的研究,进一步明确其设防目标;研究填充墙与框架的相互作用,设计新型的填充墙体系以实现校舍建筑在不同地震水平下的功能要求.     

某教学楼框架结构的抗震加层加固设计

介绍了某混凝土框架结构教学楼使用屈曲约束支撑的加层改造和抗震加固设计。工程中采用钢结构将已有的4层混凝土框架结构增加到7层,增层后混合结构的自震周期加长,侧向变形增大,地震层剪力增大。设计中对原有混凝土梁柱和基础采取了包钢和加大截面等加固方法;通过增加屈曲约束支撑调整增层后结构的刚度分布,增加结构的冗余度,显著改善了结构破坏机制,提高了加层后结构的抗震能力。还给出了加层钢柱脚节点等关键构造的做法,为类似加固加层改造工程提供参考。     

中小学砌体结构校舍的隔震加固技术研究

本文以抗震设防8度区的山西省某小学4层砌体结构教学楼抗震加固为背景,探讨了采用隔震技术对多层砌体房屋进行抗震加固的计算分析方法、施工工艺及相应的关键技术。结果表明,叠层橡胶垫基础隔震加固可以有效降低上部结构所受的地震作用,能够在一定程度上提高工程结构的安全性,是一种比较有效的建筑抗震加固技术。在高烈度区对砌体结构校舍进行抗震加固时,采用隔震加固技术比传统加固方法更具有优势。相关成果对于中小学砌体结构校舍抗震加固具有重要的参考价值。     

汶川地震中极震区砌体结构教学楼典型震害分析

汶川8.0级大地震造成了巨大的损失,大量学校建筑遭受严重破坏,其中大部分是砌体结构教学楼。在此次地震中,极震区北川县擂鼓镇城区内的初中、小学和幼儿园等砌体结构教学楼的破坏极其严重,结构特征和震害现象十分典型。本文详细地介绍了擂鼓镇城区内5栋砌体结构教学楼的结构构造特点和震害现象特征,同时,总结归纳了砌体结构教学楼的典型震害并分析了震害原因;讨论并分析了建筑含墙率、开间大小、高宽比等因素对建筑的抗震能力的影响;通过结构易损性分析方法对教学楼在不同烈度下的破坏状态进行了计算,并与实际震害进行了对比分析;最后,为灾后教学楼的重建工作提出了建议。     

某教学楼框架结构的黏滞阻尼器减震加固设计

介绍了位于抗震设防烈度Ⅶ度区的某中学6层教学楼所采用的黏滞流体阻尼器的消能减震加固的计算和设计。该教学楼为现浇混凝土框架结构,考虑到其建筑使用功能和抗震要求,在1~6层优化布置了52套黏滞流体阻尼器,时程分析结果表明:黏滞流体阻尼器可大量耗散地震动能量,显著降低了结构的地震响应。     

某大坡度屋顶结构教学楼的抗震加固设计

分析了某旧教学楼抗震性能上存在的问题,从震害机理上阐述了砌体结构的薄弱环节所在及加固所起的作用,基于结构整体受力性能的考虑和建筑使用功能的要求,提出了加固的措施,使抗震加固和建筑风格协调得到了有机统一.     

某小学砖混结构教学楼的抗震鉴定与加固方法研究

砖混结构目前在我国的中小学校舍中的存量较大,但相当数量的校舍的综合抗震能力存在问题,对其进行抗震鉴定很有必要。通过对某小学教学楼进行现场检测并依据检测结果对结构进行承载力复核验算,根据《建筑抗震鉴定标准》(GB 50023-2009)中相关要求对结构进行抗震鉴定,根据抗震鉴定的结果提出加固处理方案,并对加固原因以及加固方法进行探讨。     

汶川地震中小学砖混结构教学楼震害特征分析

根据都江堰、彭州、崇州、绵竹四地中小学72幢砖混结构教学楼震害调查资料,按教学楼所在地区峰值加速度分类,分析了砖混结构教学楼的震害特征.震害统计数据表明带壁砖柱是此类结构的抗震薄弱环节.以此为基础,提出了砖混结构教学楼抗震设防的若干建议,可供此类结构教学楼设计和施工参考.     

基于组合赋权法与TOPSIS法的砌体结构加固方案优选

砌体加固方案优选方法对实际工程遴选方案具有重要意义。为此建立了组合赋权法与TOPSIS法相结合的砌体结构加固方案优选方法，引入加固效费比模型，以效费比值为定量指标，以施工工期、施工技术、效果、整体效应4个因素作为定性指标，建立砌体结构抗震加固优选方案指标体系。以某教学楼为例，运用G1-COWA组合赋权法与TOPSIS法，求出该结构最佳加固方案为板墙加固方案。结果表明：所提出的优选方法具有一定的实用性和有效性，也适用于一般砌体加固改造工程；优选方法能根据既有结构的基本信息，科学便捷地决策出最佳方案，为砌体结构的加固设计实施提供更科学的技术支撑。     

屋盖悬挑端加固减振试验研究

大跨网架屋盖挑檐部分风致响应较大,提出附加杆件、粘弹性阻尼器及粘滞阻尼器三种加固减振方法。设计制作正置四角锥体单元空间网架足尺子结构试验模型,基于带悬挑平屋盖风压分布风洞试验数据,对三种加固足尺子结构试验模型进行不同风向角下风荷载时程的加载。分析结构风致加速度与位移响应,结果表明:附加杆件加固后网架刚度增大,加速度响应增大,位移响应减小;附加粘弹性阻尼器,结构加速度与位移响应均降低;附加粘滞阻尼器,结构加速度响应减小,位移减小效果不明显。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Solute concentrations in the lower niger river and the source rock contribution

Water quality analyses for the Niger River for the 1980/81 hydrological year are presented. The samples were collected from the main river at Lokoja, and from two main tributaries, the Kaduna and the Benue Rivers. Different water types were distinguished by the concentrations of major ions. The type Ca > Na > Mg > K - HCO₃ > SO₄ > Cl was represented at all stations during at least part of the year. Chloride was found to dominate the sulphate ion in the Kaduna and Niger, while the Benue maintained a higher concentration of sulphate relative to chloride all year round. Distinct patterns of seasonal variation in the ion concentrations were observed, particularly for the samples collected at Lokoja. Low ion concentrations were prominent during periods of high discharge, while low flow periods coincided with high dissolved ion concentrations. The contribution of rainwater to the total dissolved solids in the river waters was assessed indirectly using rainwater chemistry data from the Gulf of Guinea. The estimated rainwater contribution to the Lower Niger amounts to 5.15 mg 1^?1. Geochemical weathering calculations involving reactions of the four major minerals of granitic rocks - anorthite, biotite, albite, and K-feldspar - with carbon dioxide and water, can account for the average water composition of the Lower Niger. The proportion of the ionic components was also related to the occurrence of the respective element in the minerals.