单檐歇山式木构古建抵抗极端烈度地震试验调查研究

为更好地保护我国古建筑,基于《单檐歇山式古建筑抗震性能振动台试验》的相关成果,研究了强震作用下我国明清官式木构古建的抗震性能,制作了与该论文相同的试验模型,进行了振动台试验。通过对模型输入烈度逐渐增强的1940年El-centro波,并考虑地震波为水平双向作用,分析了强震作用下不同构造的试验现象,开展了详细的震后调查,获得了不同构造在强震作用下的抗震性能和震害机制。结果表明:强震作用下,我国明清官式木构古建的振动形式表现为柱架、斗拱、梁架及屋顶的近似同步往复摇摆;主要震害包括柱底偏移、榫卯节点开裂、拔榫、斗拱偏移及错位、额枋-垫板分离、墙体倒塌等,但承重木构架受损不严重,结构未产生倒塌。其良好抗震性能的原因与古建筑的构造特征密切相关。     

故宫太和殿动力特性与常遇地震响应

为更好地保护故宫太和殿,采用有限元分析方法,研究了太和殿的动力特性及常遇地震作用下的响应。采用弹簧单元模拟榫卯节点及斗拱构造,并考虑柱础为铰接,建立了太和殿有限元模型。通过模态分析,获得了太和殿基频及主振型;通过对模型进行时程分析,获得了典型节点的位移、加速度响应曲线,以及典型单元的内力响应曲线,评价了太和殿的抗震性能。结果表明:太和殿基频为0.9Hz,主振型以平动为主;常遇地震作用下,太和殿能保持稳定振动状态,结构的内力和变形均在容许范围内,且斗拱及榫卯节点均能发挥一定的减震作用。     

故宫太和殿结构现状数值模拟研究

为保护故宫太和殿,采用数值模拟方法,研究了太和殿的结构现状特征。采用ANSYS有限元程序,考虑榫卯节点、斗拱连接等构造,建立了太和殿有限元模型。分别对模型进行自重作用、风荷载作用下的静力分析及8度常遇地震作用下的时程响应分析,获得了太和殿在不同荷载作用下的内力及变形分布特征,评价了太和殿的结构安全现状。结果表明:重力及风荷载作用下,太和殿结构的内力、变形均在容许范围内;地震作用下,结构保持稳定状态,且榫卯节点及斗拱构造有利于减震。因此,太和殿结构现状是安全的。     

不同方法加固古建筑榫卯构架抗震试验

为保护古建筑,采用试验方法,研究了不同方法加固榫卯节点后木构架的抗震性能。基于故宫太和殿某开间梁柱节点的具体尺寸,制作了1:8比例的4梁4柱木结构空间框架模型,其中梁和柱考虑为燕尾榫形式连接。采用人工加载方式,进行了低周反复加载试验,研究了马口铁、CFRP布和钢构件加固榫卯节点后对木构架抗震性能的影响。基于试验结果,获得了加固前后构架的力-侧移滞回曲线和骨架曲线,分析了构架耗能能力、刚度退化规律及变形能力,对不同方法加固木构架的抗震效果进行了对比,对其工程应用提出了建议。     

滚珠式文物展柜隔震装置性能试验

为有效减小馆藏浮放文物的震害,研制了一款滚珠式文物展柜水平隔震装置。制作了2个文物展柜模型,并在各模型内浮放文物仿品。分别考虑文物展柜底部安装隔震装置、展柜底部浮放地面,进行了振动台对比试验,检测了隔震装置的效果。结果表明:与非隔震条件相比,隔震体系的基频减小,阻尼比增大;地震作用下,隔震体系中的文物仿品产生的位移、加速度峰值明显减小。但是隔震条件下,文物仿品的动力放大系数仍有大于1的情况,且隔震装置的复位能力尚需提高。建议对隔震装置采取的改进措施主要适当减小基频、增大阻尼比、提高加工精度等。     

明清古建筑木结构典型抗震构造问题研究

为保护古建筑,采用分类统计方法,研究了我国明清古建筑木结构的典型抗震构造问题。基于大量工程现场勘查结果,对古建筑木结构的典型抗震构造问题进行了归纳汇总,分析了原因,提出了加固建议;基于典型算例,对古建筑木结构加固方法进行了深入论证。结果表明:我国古建筑木结构的柱子、斗棋、榫卯节点、梁架、屋顶等各部位都容易产生开裂、糟朽、变形、拔榫等抗震构造问题并影响结构的抗震性能,而这些问题的产生原因主要与木结构的构造特征、木材材料性质及施工保养等因素有关;对这些抗震构造问题及时采取合理有效的加固措施,可减轻或避免结构产生的震害。     

传统方法加固馆藏浮放文物抗震性能试验

为探索馆藏浮放文物的有效抗震加固方法,采用振动台试验手段,研究了传统方法加固浮放文物的抗震性能。基于故宫博物院某展柜原型尺寸,制作了1:1比例陈列柜模型。在陈列柜内浮放一轻质陶瓷文物,分别考虑采用砂子、塑料卡、鱼线、橡皮泥及磁铁加固文物,进行了振动台试验。通过白噪声激励,获得了陈列柜基频分布;通过输入不同强度、不同类型的地震波,获得了不同方法加固条件下陈列柜和文物的位移响应、加速度响应和和动力放大系数,评价了不同方法的加固效果。结果表明:陈列柜的基频与输入地震波相差较大,这是陈列柜震害不明显的主要原因之一;传统方法加固文物后,输入地震波的加速度仍有一定放大,但是与加固前文物相比,文物的位移和加速度响应均有所减小,且文物因摇晃幅度而产生倾覆的可能性减小。此外,从减小文物加速度响应峰值角度考虑,橡皮泥和鱼线加固文物效果优于其它方法。试验结果可为文物防震保护研究提供较全面的参考。     

马口铁加固古建筑榫卯节点抗震试验

为保护古建筑,采用试验方法,研究了马口铁加固古建筑榫卯节点后对节点抗震性能的影响.基于故宫太和殿三次间结构原型,制作了1:8缩尺比例的木结构空间框架模型,并考虑梁柱连接为燕尾榫形式,进行了低周反复加载试验,其中未加固构架和马口铁加固构架试验各做了3组.基于试验相关数据,获得了节点的弯矩-转角滞回曲线和骨架曲线,并对比分析了节点加固前后的耗能能力,刚度退化和延性等抗震指标.结果表明:马口铁加固榫卯节点后,虽然节点耗能能力略有下降,但节点拔榫量减小,抗弯承载力提高,刚度退化不明显,且节点仍具有较好的变形能力.因此,马口铁具有较好的加固效果.     

石佛像减隔震保护研究

为研究预防性保护—减隔震技术在地面浮放石像文物中的应用,基于规范公式首先确定了佛像的隔震系数和支座刚度范围,进而采用时程分析程序对初选的减隔震支座进行了数值仿真验证,研究了高宽比为5.6的石佛像采用减隔震支座的可行性问题。研究结果表明:处于高烈度区浮放于地面的具有较大高宽比的石佛像文物的抗震性能存有隐患,科学合理的减隔震支座用于佛像等结构物可取得显著的减震效果。本研究所做石佛像减隔震设计及分析验证思路对类似工程有借鉴意义。     

武陟县陶楼是四阿顶不是歇山顶——兼谈汉代的歇山屋顶

《中原文物》1983年第一期发表的《武陟出土的大型汉代陶楼》一文,在描述陶楼的形制时,称“(陶楼)三檐歇山式建筑……。”仔细观察发表的陶楼照片,发现楼顶不是歇山顶,而是四阿顶(明、清时称庑殿顶)。房顶是中国木构建筑的最重要部分,它决定着房屋建筑的形制。在古代,按照封建统治者所规定的制度,屋顶的形式是有严格等级差别的,不允许随便乱用。通常以重檐庑殿为最高等级,如北京故宫的太和殿和明长陵棱思殿等。重檐庑殿(四阿顶)以下的     

Being a tourist as a chosen experience in a proximity destination

ABSTRACT

Being a tourist is not a passive attitude. It is the result of a conscious decision essentially based on how individuals build what they perceive as unknown and how they decide to get to know it. In other words, tourists deliberately create a distance with the destination which allows them to enjoy the tourist experience as something exceptional. This paper is part of ongoing research and focuses on the subjective construction of the otherness, since this process determines what is left to be discovered. First, a theoretical overview will introduce the concepts of usual environment, proximity and tourist. Then, we will focus on guided tours as a mechanism of mediation between individuals and places. Finally, we will move on to the case of Barcelona's walking tours and the local participants’ experience as a way to adopt a tourist's approach. Preliminary results show, first, four categories of experience of proximate guided tours: educational, expert, recreational and tourist. Then, they focus on the proximity tourist experience using Urry and Larsen's notion of the ‘tourist gaze’ and Tuan's theory on the tourist and the resident's points of view. According to these theories, participants’ motivations and their individual frame of reference define a tourist's point of view. Based on that, results show that proximity tourists and traditional tourists share curiosity as motivation but do not have the same points of reference. In spite of that, the feeling of proximity with the destination does not constitute a barrier to become a tourist. It is the conscious adoption of the tourist's role which makes the individual gaze upon the visited areas like a tourist, regardless of the proximity with the environment. This approach of proximity tourism constitutes a way to enhance familiar places and develop tourism in an environmentally concerned context where proximate destinations are being promoted.     

Ken Bullough: a scientist and a friend

The contributions made by Ken Bullough (1927–1994) to space physics and conflict research are briefly summarised. This brief obituary and review of his scientific contributions is supplemented by a complete list of his publications.     

Pollen analysis of a soil sample associated with a Greek cult statue as a guide to provenance

A Classical Greek cult statue of a Goddess, “Aphrodite”, currently on display in the J. Paul Getty Museum has recently been reclaimed by the Italian government. The statue is thought to have been sculpted between 425 and 400 B.C. in southern Italy or Sicily, but its provenance is obscure. Soil incorporated into the true right arm socket of the acrolithic statue at the time of burial was pollen analyzed to provide information on its geographic origin. Since palynomorphs are often not well preserved in soils, a preliminary study was undertaken to investigate preservation and abundance of palynomorphs to determine the potential benefits of undertaking further analyses. Although concentration was low, the soil contained sufficient pollen and spores to determine the environment in the vicinity of the burial site of the statue. The landscape had been cleared of natural arboreal vegetation and intensively cultivated. Juglans regia and cereals were cultivated, and pastoralism may have been practiced. A specific geographic location could not be inferred without comparative soil analyses.     

Geographical testimony: a short history of a Yugoslav family

ABSTRACT

I attempt in this essay to travel outside of and beyond the more spectacular or established geopolitical discourses associated with research on post-conflict regions, and follow instead the trail of another more essential or everyday history and geography. Listening to and responding to the testimony of a single Yugoslav family, I draw from and write of memories of former places, initially returning to the traumatic moments of 1992, and a journey across Europe. In so doing, I reflect upon the use of testimony in geographical writing, positioning it as an inherently geographical psychoanalytic technique, which not only eases suffering in individuals and communities, but also offers new possibilities for societal change and transitional justice in post-conflict regions.