钢筋混凝土异形柱框架-短肢剪力墙结构振动台试验研究

异形柱框架-短肢剪力墙结构是介于异形柱框架和异形柱框架-剪力墙结构之间的一种新型结构体系。本文通过对一幢12层钢筋混凝土异形柱框架-短肢剪力墙结构1/7比例模型的地震模拟振动台试验,系统研究了该结构体系的动力特性、地震反应及破坏机理等。试验结果表明,该结构体系属于梁铰破坏机制,能满足延性设计要求,且具有良好的抗震性能和较强的抗震能力,达到了抗震设防标准。因此,该结构体系较适用于小高层住宅结构设计。     

异形柱组合框架结构力学性能有限元对比分析

对钢筋混凝土异形柱承载力低、轴压比限值低、节点薄弱和抗震性能不理想等特点,将异形柱分别与型钢混凝土结构和钢管混凝土结构相结合,基于OpenSees建立三层两跨平面实腹式异形柱中框架模型,进行静力推覆分析和滞回性能分析,通过改变轴压比参数,获得结构滞回曲线和骨架曲线,进一步分析其承载力、延性和耗能等相关力学特性。研究结果表明:同钢筋混凝土异形柱框架相比,型钢混凝土异形柱框架和钢管混凝土异形柱框架的承载力和延性均有提高;随着轴压比增大,两种异形柱框架的弹性刚度基本不变,但荷载一顶点位移曲线下降段越陡而导致延性降低;同样配筋率下,钢管混凝土异形柱框架的承载力和延性均高于型钢混凝土异形柱框架,并且可以提高施工速度;相关研究成果可为科研和工程设计提供研究参考。     

SRC异形十字边框柱-RC剪力墙抗震性能分析

针对钢筋混凝土剪力墙抗震性能不足的缺陷,在剪力墙的边缘设置SRC异形边框柱,提出了一种新型混合剪力墙结构。为验证SRC异形十字边框柱-RC剪力墙的抗震性能,基于开源分析程序Opensees,剪力墙采用分层壳单元,外围SRC异形柱框架采用纤维梁柱单元,对缩尺比为1∶2.5的模型结构进行静力弹塑性分析和滞回性能分析。得到构件不同轴压比情况下的pushover曲线、边框柱、剪力墙承担的剪力分配情况、滞回曲线以及等效粘滞阻尼系数。研究结果表明:剪力墙承担了大部分剪力,相比于RC剪力墙,SRC异形边框剪力墙的延性、抗剪承载力、极限位移以及耗能能力均有不同程度的提高,并且随着轴压比增大,提高系数下降。设置SRC异形边框柱有效地改善了RC剪力墙在地震作用下的抗震性能。     

震损钢筋混凝土框架柱加固修复试验研究

以地震损伤钢筋混凝土框架柱为研究对象,重点研究了损伤、加固后的钢筋混凝土框架柱的抗弯、抗震性能及加固措施。设计并制作了6根钢筋混凝土柱试件。第一步,对原试件进行损伤试验;第二步,对损伤柱试件进行碳纤维加固和钢板加固,试验分析加固试件的抗震性能。考虑了不同轴压比与加固方式等参数的影响,对比研究不同轴压比作用下,采用不同加固方式柱试件的滞回曲线、骨架曲线、耗能、延性及破坏形态等抗震性能,并对不同加固方案的效果进行分析比较,揭示了不同变化参数对加固后柱的抗震性能等指标的影响规律与程度,为我国建筑抗震设计规范和混凝土结构加固规范的修订提供试验和理论参考。     

混凝土梁式托柱转换层结构抗震性能分析

正确认识梁式托柱结构的抗震性能,是对此类型转换层结构进行合理抗震设计的基础。以某多层带梁式托柱转换层的钢筋混凝土框架为研究背景,分别建立了3种不同柱截面尺寸的梁式托柱转换层结构有限元模型,采用Pushover方法对结构进行静力弹塑性分析,分别对小震和大震下具有不同柱截面尺寸的梁式托柱转换层结构的层间位移反应和塑性铰分布状态进行了分析比较,评价了梁式托柱转换层结构的抗震性能,并给出有益的设计建议。结果表明:小震作用下,柱截面尺寸变化对转换层下部结构的位移响应影响较小,转换层上部结构的层间位移角发生突变,且随着上托柱截面尺寸的增大,层间位移角表现出减小的趋势;大震作用下,柱截面尺寸变化对梁式托柱结构的层间位移角影响更大。此外,在转换层处和底层框架中易出现"强梁弱柱"现象。     

带防屈曲支撑的钢管混凝土框架抗震性能参数分析

设置防屈曲支撑的钢管混凝土框架是一种新型钢管混凝土减震结构。采用有限元软件Opensees对设置防屈曲支撑的单层单跨钢管混凝土减震框架进行数值模拟,研究了框架梁柱线刚度比、防屈曲支撑初始刚度以及钢管混凝土柱轴压比等设计参数对该减震结构抗震性能的影响。研究结果表明:1数值模拟和试验结果吻合较好,验证了有限元模型的正确性;2梁柱线刚度比在0.1~0.3之间变化时,钢管混凝土减震框架的抗震性能较好;3BRB耗能支撑的初始刚度K1在40~80kN/mm变化时,减震框架的耗能减震效应较明显;4在合理的钢管混凝土柱轴压比范围内,当轴压比较大时,在钢管混凝土框架中设置防屈曲支撑能明显地提高结构的耗能能力和改善结构的强度退化现象。     

框架柱抗震抗火设计因素分析

在介绍地震火灾危害基础上,分析了钢筋混凝土框架柱地震与火灾引起的破坏形式,论述了同时考虑抗震与抗火的钢筋混凝土框架柱相悖与相符的设计因素及其依据,给出了相悖设计因素的弥补方法。相关结论对需要同时考虑抗震与抗火的钢筋混凝土框架柱的设计具有一定的指导意义。     

基于NetSLab远程协同试验平台的多跨桥梁抗震研究

利用远程协同试验平台NetSLab,对一个多跨的桥梁结构进行了抗震试验研究。该平台是基于客户机/服务器概念开发的,提出了供结构拟动力远程试验用的数据模型和应用协议。它能够在远程结构实验室或计算机之间通过互联网传送控制和反馈数据。桥梁系统由3个柱子组成,分别在湖南大学、哈尔滨工业大学和清华大学之间模拟。湖南大学站点试验模型为GFRP约束弯曲型钢筋混凝土桥墩柱,哈尔滨工业大学站点试验模型为CFRP约束剪切型钢筋混凝土桥墩柱,清华大学站点则进行数值模拟。对该桥梁进行了3个水准地震作用下的远程协同拟动力试验,地震动加速度选用E l Centro波。试验结果表明,GFRP加固柱具有良好的延性及抗震性能,CFRP加固可阻止柱子的脆性剪切破坏,有效地提高其滞回性能及能量耗散能力,从而可大大地提高整个桥梁系统的抗震能力。     

装配式RCS框架-屈曲约束支撑组合结构抗震性能研究

将屈曲约束支撑应用于装配式钢筋混凝土柱-钢梁组合框架结构(简称装配式RCS组合框架结构)中,若处理不当将会产生开合效应并导致相邻梁柱破坏。为有效减轻框架开合效应造成的破坏,提出基于梁端铰接的装配式RCS框架-屈曲约束支撑组合结构。在保证关键连接节点力学性能的前提下,设计某9层装配式RCS框架-屈曲约束支撑组合结构,采用基于OpenSees软件的动力弹塑性时程分析方法研究结构的抗震性能。结果表明,钢梁腹板开洞的装配式RCS节点、装配式混凝土柱-钢梁-屈曲约束支撑组合节点具有高承载、可装配和震后损伤小等特点,装配式RCS框架-屈曲约束支撑组合结构满足抗震规范要求,具有优良的抗震性能;梁-梁间的铰接连接不会影响屈曲约束支撑的耗能效果,且可以改变梁柱屈服机制,保证整体结构高效装配的同时减轻结构塑性损伤,有助于实现结构的功能可恢复。     

新型可恢复功能组合柱设计及其抗震性能研究

为实现框架结构震后性能的快速恢复，提出了一种有良好自复位能力且易于修复的新型可恢复功能组合柱。考虑钢绞线滑移及无粘结钢绞线的受力特征，采用OpenSees对柱抗震性能进行验证及参数分析。对不同设防烈度普通钢筋混凝土(reinforced concrete, RC)框架、钢绞线混凝土框架及应用可恢复柱的可恢复框架进行静力推覆及地震荷载下的残余位移及最大位移响应分析，得出各框架层间最大位移与残余位移的关系，并对比分析各框架在不同地震强度下的可恢复性能。结果表明：钢绞线配置率对可恢复柱的抗震性能有重要影响；7度设防RC框架应用可恢复柱后，底层梁柱塑性铰发展大幅减轻，延迟了框架的破坏，且其承载能力与自复位能力均高于8度设防RC框架；在地震作用下可恢复框架的失效概率最低，可恢复性最高，且地震作用越大，其相对于普通RC框架可恢复性的提升越为明显。     

Cholera in Sudan: An account of an epidemic in a refugee camp in eastern Sudan, May-June 1985

In 1985 cholera has been a serious problem in the horn of Africa, particularly affecting the many famine victims and refugees in that region. In this paper the history of cholera in Africa is briefly summarized, as is the background to the current refugee situation in eastern Sudan. A cholera epidemic involving 1,175 cases in two adjacent refugee camps in eastern Sudan is described. In this epidemic there were thirteen inpatient deaths and thirty-eight known home deaths from cholera. The management of the epidemic is described in detail. Overall an average of 8 1. of intravenous fluid was used per case, a higher figure than was anticipated, probably because of the unexpected degree of vomiting and the shortage of trained nursing staff.
The relationship between cholera and malnutrition is explored and hypochlorhydria is suggested as the main reason for the increased susceptibility to cholera among malnourished populations. It was observed that severely malnourished adults and children appeared to nave less severe diarrhoea with their cholera, presumably because of reduced mucosal surface area and poor enterocyte function. Finally possible means of aborting cholera epidemics are discussed.     

A retrospective statistical review of deaths owing to migration through the southeasternmost land borders of the European Union,Greece 2000–14

The land borders of Evros, Greece, have been a common entry point for undocumented migrants on their way to Europe through Turkey. Adverse conditions, however, have resulted in many human casualties over the years. On the Greek side, 334 cadavers were retrieved between 2000 and 2014. This study provides a detailed forensic account of the humanitarian disaster in Evros to create an official scientific record of the situation. It showcases the gravity of the global issue of migration relating to health and mortality, and encourages communication and continual improvement of the approach and patterns of practices surrounding the subject. A retrospective statistical research review was conducted of border‐related fatalities between 2000 and 2014, assessing the age and gender of victims, the cause of death, the location of bodies, identification rates, and country of origin. Age ranged generally from 24 to 29 years, but infants and children were among the deceased.     

Complexity,continuity and change: livelihood resilience in the Darfur region of Sudan

Darfur farming and pastoralist livelihoods are both adaptations to the environmental variability that characterises the region. This article describes this adaptation and the longer‐term transformation of these specialised livelihoods from the perspective of local communities. Over several decades farmers and herders have experienced a continuous stream of climate, conflict and other shocks, which, combined with wider processes of change, have transformed livelihoods and undermined livelihood institutions. Their well‐rehearsed specialist strategies are now combined with new strategies to cope. These responses help people get by in the short term but risk antagonising not only their specialist strategies but also those of others. A combination of factors has undermined the former integration between farming and pastoralism and their livelihood institutions. Efforts to build resilience in similar contexts must take a long‐term view of livelihood adaptation as a specialisation, and consider the implications of new strategies for the continuity and integration of livelihood specialisations.     

Risk communication in emergency response to a simulated extreme flood

Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties.     

Fiji, land of tropical cyclones and hurricanes: A case study of agricultural rehabilitation

Tropical cyclones and hurricanes have a severe impact on the social and economic activities of affected communities. For small island nations in the Pacific region, the effects can be devastating because of their smallness. FQi and several other countries in the region are vulnerable to such disasters as they are situated in the zone where cyclones occur frequently.
During the last decade, the frequency of natural disasters and their adverse impact on die economic and social development of small nations like Fiji, has aroused awareness mat relief efforts must go beyond immediate "mopping up" operations to those which contribute to attaining longer term benefits through reconstruction and rehabilitation.
The paper outlines the 1985 agricultural rehabilitation program and discusses related issues and problems.     

Risk and the neoliberal state: why post-Mitch lessons didn't reduce El Salvador's earthquake losses

Although El Salvador suffered light losses from Hurricane Mitch in 1998, it benefited from the increased international aid and encouragement for advance planning, especially mitigation and prevention interventions. Thus, one would have supposed, El Salvador would have been in a very advantageous position, able more easily than its economically crippled neighbours, Honduras and Nicaragua, to implement the 'lessons of Mitch'. A review of the recovery plan tabled by the El Salvador government following the earthquakes of early 2001 shows that despite the rhetoric in favour of 'learning the lessons of Mitch', very little mitigation and prevention had actually been put in place between the hurricane (1998) and the earthquakes (2001). The recovery plan is analysed in terms of the degree to which it deals with root causes of disaster vulnerability, namely, the economic and political marginality of much of the population and environmental degradation. An explanation for the failure to implement mitigation and preventive actions is traced to the adherence by the government of El Salvador to an extreme form of neoliberal, free market ideology, and the deep fissures and mistrust in a country that follow a long and bloody civil war.     

Epidemiology of tornado destruction in rural northern Bangladesh: risk factors for death and injury

The epidemiology of tornado-related disasters in the developing world is poorly understood. An August 2005 post-tornado cohort study in rural Bangladesh identified elevated levels of death and injury among the elderly (≥ 60 years of age) (adjusted odds ratio (AOR) = 8.9 (95 per cent confidence interval (CI): 3.9-20.2) and AOR = 1.6 (95 per cent CI: 1.4-1.8), respectively), as compared to 15-24 year-olds, and among those outdoors versus indoors during the tornado (AOR = 10.4 (95 per cent CI: 5.5-19.9) and AOR = 6.6 (95 per cent CI: 5.8-7.5), respectively). Females were 1.24 times (95 per cent CI: 1.15-1.33) more likely to be injured than males. Elevated risk of injury was significantly associated with structural damage to the house and tin construction materials. Seeking treatment was protective against death among the injured, odds ratio = 0.08 (95 per cent CI: 0.03-0.21). Further research is needed to develop injury prevention strategies and to address disparities in risk between age groups and between men and women.     

火灾场景中玻璃破裂行为研究综述

建筑物在火场中的结构响应问题中,门窗玻璃在火场中的热响应特性及破裂脱落是影响火灾发展的重要因素之一。通过事故案例分析了火灾场景中玻璃破裂脱落的危害性,指出了研究火灾场景中玻璃受热破裂脱落的意义,并对目前火灾场景中玻璃受热破裂过程和主要形态、玻璃的破裂机理和判据等的研究现状进行了详细的分析,总结了目前实验和计算机模拟的最新研究进展和不足,为今后进一步开展玻璃受热破裂脱落研究提出了若干建议。     

中国内陆自然环境的干旱化与未来趋势

根据中国内陆陕西、甘肃部分地区５０９ａ旱涝资料和主要测站气象、水文实测数据,应用Ｗｏｒｄ９７图形处理系统,证明在５２６ａ序列中目前处在１１ａ、５０ａ滑动的干旱期。近４６ａ气温上升了０．３℃,年降水减少了８０ｍｍ,径流量减少了０．７８％,出现了明显的干旱化,环境变化趋势不容乐观。