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。     

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。     

西藏坚塞颇章宫的结构计算分析

本研究以全国重点文物保护单位西藏罗布林卡三大宫殿之一的坚塞颇章宫为实例,分析藏式古建筑的结构特点,探讨计算分析方法,并针对静力荷载工况和地震组合工况下的结构性能进行了讨论。本研究区别于以往藏式结构的研究方法,主要在于:在计算分析中将墙体建入整体结构模型,考虑墙体对结构的影响;考虑墙体和木柱的“收分”造型的影响;将楼板和屋面的密布木檩等刚度转化为单向板考虑;同时考虑构件已存的变形缺陷影响。计算结果表明:西藏坚塞颇章宫在静力荷载工况作用下,整体状态良好,梁柱墙及节点均满足承载力要求;在地震组合工况作用下,部分柱和墙不满足抗震承载力要求。在地震作用下,该建筑刚度较小的木结构构件首先发生振动。结构薄弱部位是中部四根二层通高木柱。这四根通高木柱长细比较大,刚度较小,一旦发生较大的变形,将直接影响整体结构安全。木柱与墙体之间的变形差异较大,两者变形协调性较差。此外,存在变形缺陷的中部通高木柱所在梁柱节点的抗震承载力不满足要求,应注意加强防护。研究涉及的计算分析方法及相关计算结论对藏式建筑结构的深入研究具有重要的参考价值。     

应县木塔横纹承压构件GFRP棒增强加固试验研究

应县木塔建造于1056年,高达67.31m,而当时对木材横纹承压受力性能缺乏应有的知识,致使木塔下部1～3层柱顶水平木构件横纹承压应力严重超过设计值,产生不可恢复的承压变形,部分构件已严重劈裂。本文提出用玻璃纤维增强塑料(GFRP)棒局部增强横纹承压技术,短期荷载试验结果表明,组合木构件的横纹承压强度大幅度提高,刚度有所增加,其延性性能得到大的改善。在深入研究GFRP棒增强机理的基础上,提出了GFRP增强木材组合构件横纹承压承载力的简化计算公式。     

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。     

斗口跳斗拱及相关问题

一斗口跳在中国古代建筑的斗拱中是结构较为简单的一种,是斗拱出跳的简洁形式。《营造法式》卷四“大木作制度”对四至八铺作的各类斗拱结构作了较为详细的规定,唯对斗口跳和把首绞项作两项未曾涉及,卷三十和三十一“大木作图样”中也同样缺如。因此,斗口跳拱的具体作法在《法式》中并不明了。但在卷十七“大木作功限”中规定了“斗口跳每缝用拱斗等数: “科口跳每柱头外出跳一朵用拱斗等下项泥道拱一只华拱头一只栌头一只交互斗一只散斗二只闇栔二条”     

地震与风作用下应县木塔结构响应及监测

应县木塔是世界建筑文化遗产的重要组成部分,具有极高的历史、文化与科学价值。为了探究在地震与风荷载作用下应县木塔的结构响应,采用梁单元建立的木塔有限元模型具有较高的准确性与可靠性;木塔在地震作用下层间位移角最大可达1/196,一定程度上会对木塔结构产生破坏;木塔在风振作用下会产生较大水平加速度,威胁木塔上的文物;基于木塔的地震与风振响应,提出了关注脆弱构件的残损监测、木塔构件变形监测、木塔振动监测与传递监测等四条建议。旨在为木塔进一步监测与有效保护奠定基础。     

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.     

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。     

清式木建筑透榫节点加固方法的试验研究

我国传统木结构建筑的各构件间主要采用榫卯连接,这种节点形式在较大水平地震作用下容易出现局部拔榫、节点松脱现象,不利于结构的稳定和承载。为此针对榫卯节点的抗震性能及加固进行试验研究。依据清工部《工程做法则例》设计制作了4个足尺透榫节点试件,其中3个试件分别采用竹斜撑、角钢和碳纤维(简称CFRP)布进行加固。在改进榫卯节点拟静力试验装置的基础上完成了低周反复荷载试验,分析了对比节点和加固节点的破坏机理、承载力、延性、刚度退化、耗能和榫头拔出过程。试验结果表明,竹斜撑、角钢和CFRP布加固节点的正向峰值荷载较对比节点分别提高了92.4%、54.6%和63.0%,反向峰值荷载则分别提高了61.5%、75.7%和39.0%。对比节点和角钢加固节点初期刚度基本相同,且随转角增加出现先增大后减小的过程;竹斜撑加固和碳纤维布加固节点的初始刚度显著大于对比节点,随着转角的增加呈单调减少。此外,竹斜撑和角钢加固节点的榫头拔出长度明显小于相同转角下对比节点的榫头拔出长度,表明竹斜撑和角钢均起到了延缓榫头拔出的作用。     

Das Wissen der Schulden. Recht,Kulturtechnik und Alltagserfahrung im liberalen Kapitalismus

The Knowledge of Debt: Law, Media Technique, and Everyday Experience in Liberal Capitalism. Performing an object such as ‘the economy’ hinges on practices of formatting knowledge. The article proposes to look at such instituting moments in connection with social conflicts over the legitimate rules of exchange. This is exemplified by way of recounting the story of the codification of Swiss bankruptcy law in 1889. In order to homogenize the legal procedures of debt collection and bankruptcy, two subject categories were instituted: ‘merchants’ and ‘non-merchants’. These different categories were thought to account for the diverging temporalities and spaces of credit exchange in everyday economic life. The introduction of the commercial register, a media-technical apparatus, enabled a formal distinction between ‘merchants’ and ‘non-merchants’. However, this boundary was contested and proved to be porose.     

Studies on amerindian dogs, 1: Carbon isotopes in relation to maize in the diet of domestic dogs from early Peru and Ecuador

Work initiated purely as a dating project in support of a craniometric and morphological investigation of domestic dogs from early Peru has proved to have much wider implications. The stable carbon isotoperatios (¹³C/¹²C) of hair samples from ten dogs show that maize formed a significant part of their diet. Radiocarbon dates for these remains have confirmed that they belong to the period well after the cultivation of maize was first established. Stable carbon isotope measurements can thus be used to test for the presence of maize as a dietary constituent at earlier sites even where there is otherwise only indirect evidence for its cultivation. Collagen from animal or human bone is a suitable alternative to hair for this purpose and the method has been successfully applied to collagen dating to c. 3000 BC from the Valdivia culture site of Real Alto, Ecuador, as well as to a series of early Peruvian dogs.     

Two radiocarbon dates for freshwater shells from hierakonpolis: Archaeological and geological interpretations

Shells of two species of freshwater bivalve (Unio willcocksi Bullen Newton and Etheria elliptica Lamarck) from the predynastic Gerzean (Nagada II) Decorated Tomb at Hierakonpolis, Egypt have given dates of 5000±90 bp for the tomb, and 12,900±120 bp for an episode of Nile terrace accumulation (correlated here with the Sahaba-Darau aggradation event). The archaeological and geological significance of these results is discussed, together with an outline of problems associated with radiocarbon dating of shell. Comparisons are made with the few other radiocarbon dates available for the Predynastic period in Egypt and possible reasons for the presence of shells in the tomb are considered.     

Die Kunst des Anschlags. Elisabeth Caland und die Physio‐Ästhetik des Klavierspiels

The Art of Touch. Elisabeth Caland and the Physio‐Aesthetics of Piano Playing The issue of how it is possible to play the piano without striking it was raised by Chopin: one must ‘caresser’ and not ‘frapper’ the piano. In her teachings on the art of piano playing, Elisabeth Caland (1862–1929) attempts to articulate a scientifically grounded solution to this complex (kin‐)aesthetic problem. The solution turns on her intuitively discovered ‘lowering of the shoulderblades’ which was documented in 1904, through X‐rays, by the Berlin physiologist René du Bois‐Reymond, and recorded as a way of coordinating movement which had been unknown to physiology up to that time. Caland's physio‐aesthetic of piano playing, which she worked out on the basis of du Bois‐Reymond's observations, turns on the ideal of ‘floating sound’ put forward by her teacher Ludwig Deppe, and on Ferruccio Busoni's technique of piano playing. Her method makes essential use of what Feldenkrais would later call the ‘sixth sense’ (i.e. proprioceptive perception); in fact, it represents the first modern kinaesthetically based conception of piano playing. Caland's doctrine of touch was ahead of its time and it virtually disappeared from discussions of piano technique after 1930. But it has become accessible again through reprints of her most important writings: Deppe's doctrine of piano playing (1897), Sources of power in piano playing (1904), and Artistic piano playing (1910).     

Some chronological implications of a fossil molluscan assemblage from a neolithic site at Brook,Kent, England

The later post-glacial history of a valley in the chalk escarpment near Brook, Kent, is described, based on molluscan stratigraphy, archaeological evidence and radio-carbon dating. Differences in size and colour banding, respectively, of fossil and living representatives of two species of land snails, Pomatias elegans (Müller) and Cepaea nemoralis (L.), are correlated with climatic change during the post-glacial period. The problems of the use of fossil shells of these species as samples for radiocarbon dating are discussed.     

China's Dynamic Industrial Sector: The Internet Industry

A Singapore-based economic geographer explores and analyzes the spatially uneven evolution of the Internet industry in China, arguing that the country's immense regional disparity in the provision of Internet services is best explained by the interplay of place- and path-dependence. The author demonstrates how the highly uneven regional endowments in relevant industrial and entrepreneurial resources have led to the substantial and persistent regional imbalance within China's emerging "new economy." His initial survey of the country's 100 leading Internet content providers (firms), identified from a listing of ca. 11,700 commercial websites, is selectively augmented to reflect an increase of over 70 million Internet users in 2007, reaching a total of 253 million in June 2008, and thus overtaking the United States as the world's largest Internet market. Journal of Economic Literature, Classification Numbers: L10, L86, O30. 6 figures, 1 table, 53 references.     

The 1911 International Exposition in Rome: architecture, archaeology, and national identity

This paper discusses the 1911 International Exposition in Rome and illustrates how this patriotic celebration of the fiftieth anniversary of the Italian Sate utilized symbolic landscapes of architecture and archaeology to promote nationalist sentiments of italianità and romanità centered on the young capital of Rome. Through modern art exhibitions at the Valle Giulia, scientific conferences at the Castel Sant’Angelo, archaeological exhibits on the Roman Empire in the Baths of Diocletian, and regional Italian pavilions in the Piazza d’Armi, exposition officials offered a complex representation of Italian national identity that was modern yet ancient, cosmopolitan yet bucolic, European yet regional, and imperial yet developing.     

Comparison of analytical techniques for analysis of archaeological bronze

While many analyses of archaeological bronzes have been reported in the literature, in practice it is very difficult to compare them. To assess the present status of the chemical analysis of bronze two ancient objects—a flat axe (arsenic bronze) and a sickle (tin bronze)—were cut into pieces weighing about 2 g each and were distributed to 11 laboratories. The participants used the following methods for analysis: INAA, ED–XRF, PIXE, TRXRF, FAAS, ICP–AES, ICP–MS, SEM–EDS, LA–ICP–MS and PGAA. The samples were analysed in at least quadruplicate. Dixon's and Iglewicz and Hoaglin's tests were used to detect outliers. The majority of methods provided comparable results, especially for macroelements, independent of the technique and standards used. The number of determined elements depended on the method and, naturally, on the concentration level. Therefore an important recommendation that can be made is to supply, with each archaeometric investigation, data from the analysis of appropriate Certified Reference Materials (CRMs) used in the study.