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The article presents the results of an experimental and numerical investigation on Azzone Visconti bridge, a 14th century arch bridge in Lecco (northern Italy). Starting from the historical data and from an extensive mechanical characterization of both the soil constituting the riverbed and of the masonry constituting the piers, the aim of the study is to investigate the bearing capacity of the bridge. A testing loading scheme defined according to the current Italian Code is adopted to check the structural behavior. A simplified finite element structural model was conceived and calibrated as a control tool to safely perform the experimental tests. Post-test nonlinear finite element analyses have allowed the prediction of the bridge bearing capacity and the definition of the bridge class according to the Italian regulations.  相似文献   

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我们从武英殿建筑群的武英门、武英殿、敬思殿、武英门东西值房、东配殿及北值房、西配殿及北值房、恒寿斋、井亭11座建筑的20余种木构件上,共采集1145个样本进行树种鉴定。结果表明,武英殿建筑群共使用了15个种或属的木材,其中有落叶松、软木松、硬木松、冷杉、云杉、黄杉、柏木、杉木、圆柏、金钱松等10种针叶材,桢楠、椴树、润楠、喃喃果、印茄等5种阔叶材。其中,杉木、桢楠和润楠是我国南方树种,喃喃果和印茄是东南亚进口材。武英殿主要承重木构件选用主要为北方树种中密度和力学强度较高的落叶松、黄杉和云杉,其他木构件则主要使用的是密度低、重量轻的软木松;敬思殿主要承重木构件使用的是云杉,其他木构件也以软木松为主,但使用的木材比较杂,角梁和爬梁全部使用了东南亚进口阔叶材;敬思殿在选材方面与武英殿的差异,可能是在光绪三十年重建时选材标准不如武英殿严格所致。武英门的木材,硬木松占了绝大多数,使用的都是强度较大的木材。所有配殿和值房的主要承重构件中,柱使用最多的是硬木松,其次是落叶松、软木松;月梁、三架梁和四架梁、瓜柱、四架梁随梁、抱头梁及其随梁木构件使用的是杉木,配殿、值房等建筑的梁没有使用强度高的木材。是以南方树种为主,其中某些主要构件还使用了珍贵的南方阔叶树种如桢楠、润楠等。这种情况表明,恒寿斋和井亭是武英殿几次大火后的仅存建筑,因而保留了明代建造时选材的历史信息。木材的使用差异具有一定的时代意义。从润楠在恒寿斋的柱和梁上,椴树、桢楠和润楠在斗棋上使用,以及根据构件的承重和位置不同进行树种配置,既考虑了对主要建筑结构材的强度要求,也考虑了尽可能减小其他木构件对主要构件的负荷,这种按照木材物理力学的性质和木材承重强度等因素进行选材的建筑原则,相当清楚地表明当时吉建筑在科学选材方面已达到很高的水平。在故宫维修工程中通过对各种木构件树种配置的研究,进行科学定性分析,将深层次地探索古建筑留给我们的历史痕迹和信息,揭示其科学性,为制定维修保护方案提供科学依据,并为故宫古建筑保护研究提供新的方法,丰富故宫历史档案资料。  相似文献   

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A simplified approach for analyzing the nonlinear response of masonry buildings, based on the equivalent frame modeling procedure and on the nonlinear equivalent static analyses, is presented. A nonlinear beam finite element (FE) is formulated in the framework of a force-based approach, where the stress fields are expanded along the beam local axis, and introduced in a global displacement-based FE code. In order to model the nonlinear constitutive response of the masonry material, the lumped hinge approach is adopted and both flexural and shear plastic hinges are located at the two end nodes of the beam. A classical elastic-plastic constitutive relationship describes the nonlinear response of the hinges, the evolution of the plastic variables being governed by the Kuhn-Tucker and consistency conditions. An efficient element state determination procedure is implemented, which condenses the local deformation residual into the global residual vector, thus avoiding the need to perform the inner loops for computing the element nonlinear response. The comparison with some relevant experimental and real full-scale masonry walls is presented, obtaining a very good agreement with the available results, both in terms of global pushover curves and damage distributions.  相似文献   

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ABSTRACT

The “Quartel das Esquadras” is an 18th century infantry barrack located within the limits of the bulwarked fortress of Almeida, in Portugal. An ongoing adaptive reuse project of the building aims to recover its full capacity and also its importance, by implementing a variety of new uses. The architectural intervention results in the need of the structure to withstand new and diverse imposed loads. As the current configuration of the structure will be altered, the main objective of this article is to evaluate the suitability of some of the proposed structural interventions. The current condition has been characterized following a multidisciplinary approach comprising historical research, visual inspection, non-destructive testing, and structural analysis to identify the possible sources of major structural problems. A portion of the building particularly affected by the alterations has been selected to carry out structural analysis. A comparative safety assessment of the selected area in both current and altered condition has been done through finite element modelling and nonlinear static analysis, resulting in an identification of the weaker points against the new implemented loads and alterations. Finally, proposals for the implementation of the studied intervention, as well as recommendations for future research and analyses, have been given.  相似文献   

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ABSTRACT

Historic heritage buildings are a part of historic basis of each society and an economic resource. Therefore, preserving and maintenance of these buildings are cultural, economic and social demand. This research investigates the seismic performance of a historical building named Arg of Tabriz (Arge Alishah) that dates back to 14th century and is located at the city center of Tabriz (NW of Iran). Static, modal, and finally nonlinear dynamic (time history) analysis were performed by both “Considering Soil-Structure Interaction (SSI)” and “fixed base (ignoring SSI)” Cases.

It is found from the results that, SSI extremely affects mode shapes and their frequencies and depending on the frequency content of the records, can has an incremental or decremental effect on structural responses. As expected, the building of Arg could carry gravity loads easily and despite its stability against earthquake loading in fixed base case, showed a weakness (especially in eastern and western walls direction) and overturned when it was analyzed in SSI case because of yielding of the surrounding soil.  相似文献   

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The lithic assemblage from the Middle Palaeolithic site of Payre (Rhone Valley, France) contains a large number of convergent tools and pointed tools of various shapes, sizes and retouch types. These were excavated from several archaeological units, dating from marine isotopic stages 8–5, which also yielded human skeletal remains. Consideration of this large tool kit has led to an improved analysis of Middle Palaeolithic tools with two retouched convergent edges. The 350 tools were not described within the classical typological framework, but, rather, from a lithic technological perspective in relation to a discoid debitage. In addition, an initial macroscopic use-wear analysis aided in establishing whether they were used according to their technical and/or morphological features. The Middle Palaeolithic convergent tools from Payre are shown to be quite diversified, and the question of the significance of the retouch and the definition of the various types is addressed. Initial functional results indicate that a clear relationship between shape and function cannot be easily established, and that these tools were used as hand tools. This study contributes to the debate on the use of stone tip spears in the Early European Middle Palaeolithic.  相似文献   

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The presence of cobbles with activity-related marks in the Mesolithic site of Font del Ros (Berga, Spain), and in particular one group of artefacts – pitted stones – raises problematic issues associated with the characterization of percussion activities. Although these artefacts have generated an extensive bibliography on ethological, ethnographic, ethnoarchaeological and archaeological levels, various questions persist in relation to their possible contextual function. In this paper we present the results of an experimental programme in which three types of activities that could create pitted stones are reproduced: bipolar knapping of vein quartz, hazelnut cracking, and hazelnut grinding. The aim of this experimental programme is to describe marks and use-wear traces related to such activities.  相似文献   

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佛光寺东大殿实测数据解读   总被引:4,自引:0,他引:4  
结合山西省古建筑保护研究所2004年、清华大学2005—2006年对五台山佛光寺东大殿的手工测绘和三维激光扫描测量,本文借鉴前辈学者对于佛光寺东大殿原始设计尺寸权衡的论述,在今天毫米级精度的测量数据的基础上,得出以下结论:东大殿所用营造尺长298毫米,中五间开间1丈7尺,标准柱高同之;斗拱材宽7寸;斗拱下昂斜度等于总举斜度,基本斜度可描述成“平出47分~(?),抬高21分~(?)”,总举为此基本斜度的11倍,稍间、进深各间尺寸因此定为1丈4尺8寸;中平槫到柱头的高度等于总举高。通过上述的分析与结论,本文强调提高古建筑测绘数据全面性和精度的重要意义及深远的科研前景。  相似文献   

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Percussive activities are highly relevant in the economy of modern hunter-gatherer societies and other primates, and are likely to have been equally important during the Palaeolithic. Despite the potential relevance of percussive activities in the Early Stone Age, attempts to study battered artefacts are still rare. In order to establish protocols of analysis of battered tools, this paper pursues an interdisciplinary approach combining techno-typological, refit, use-wear and GIS studies of experimental anvils from Olduvai Gorge (Tanzania). The main aim is to classify types of damage on battered artefacts according to the percussive task performed, and hence identify patterns that can be used to interpret the Oldowan and Acheulean evidence. Our results indicate that abrasion marks on anvil surfaces are typical of nut cracking, while bone breaking leaves characteristic scars and abrasion marks on the edges of anvils. Pounding of soft materials such as meat and plants also causes battering of anvils, producing morphological and spatial patterns that can be discerned from the heavy breakage of anvils during bipolar flaking. By integrating macroscopic, microscopic and spatial analyses of experimental stone tools, this paper contributes to create a referential framework in which Early Stone Age battered artefacts can be interpreted.  相似文献   

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A male human skeleton from Thrace dated at around 320 BC was found in a wealthy tomb 12 km from what is now Tekirdağ, Turkey. The occupant of the tomb died at the age of 40–45 years and has a pathologic left humerus caused most probably by traumatic injury. It is 9 cm shorter than the right humerus. A drainage fistula penetrating into the medullary cavity occurs at its proximal end. Due to severe arthritic destruction, the left humeral head has completely lost normal articulation, with the glenoid cavity of the left scapula displaying, in turn, severe erosive lesions and important reduction in its articular surface. A marked abscess is discernible bilaterally on the chondro‐costal sternal end. The individual also has a hip with a total sacroiliac joint fusion and shows slight or moderately developed exostoses on different parts of his skeleton. These joint destructions most likely indicate that he suffered from chronic osteomyelitis and septic arthritis. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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故宫博物院古建筑防雷保护工作的回顾   总被引:2,自引:0,他引:2  
北京故宫在建成之时,就有雷害伴随,不断出现雷击起火,损毁建筑物的事故。本文回顾了故宫博物院上世纪50年代以来古建筑防雷工作的情况,特别是1984年国家颁布试行《建筑防雷设计规范》后,对故宫古建筑之材料进行相关的数据调查和实验,作为防雷设计的依据。同时对防雷问题较严重的几座殿宇的防雷装置的改进,大大提高了防雷保护能力。此外,作者还对故宫落雷的条件和一些雷击事故加以科学分析。  相似文献   

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New data regarding the white shark (Carcharodon carcharias) at the archaeological complex Huaca Pucllana (200–700 ad ) are presented on the basis of the recent discovery of teeth in ritual offering features. Previous information of this species from fossil, archaeological and modern records is reviewed. The use of the white sharks as an El Niño indicator is rejected. Past and present white shark distribution in the South East Pacific is reviewed, and the extermination of pinniped colonies as a factor in the poor modern record is discussed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

15.
Abstract

The site of Riparo Dalmeri yielded numerous flint, bone, and shell artifacts, as well as faunal and botanical remains, which are evidence of the Late Upper Palaeolithic (or Late Epigravettian culture, ca. 16,000–12,000 cal b.p.) occupation of the Alps region. The importance of the site is related to the discovery of 267 stones painted with anthropomorphic, zoomorphic, and geometric designs. Here we report on ground stone tools from Riparo Dalmeri investigated by means of an integrated technofunctional and experimental approach to reconstruct their production and use. The results support the hypothesis that the ground stone artifacts were employed in specialized activities (e.g., hide treatment, flintknapping) as well as in the production of some of the painted stone artifacts.  相似文献   

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The relationship between fracturing and fracture filling in opening‐mode fractures in the Triassic Buntsandstein in the Lower Saxony Basin (LSB; NW Germany) has been studied by an integration of petrographic and structural analysis of core samples, strontium isotope analysis and microthermometry on fluid inclusions. This revealed the relationship between the timing of the fracturing and the precipitation of different mineral phases in the fractures by constraining the precipitation conditions and considering the possible fluid transport mechanisms. The core was studied from four different boreholes, located in different structural settings across the LSB. In the core samples from the four boreholes, fractures filled with calcite, quartz and anhydrite were found, in addition to pore‐filling calcite cementation. In boreholes 2 and 3, calcite‐filled fractures have a fibrous microstructure whereas in borehole 1, fractures are filled with elongate‐blocky calcite crystals. Anhydrite‐filled fractures have, in all samples, a blocky to elongate‐blocky microstructure. Fractures that are filled with quartz are observed in borehole 2 only where the quartz crystals are ‘stretched’ with an elongated habit. Fluid inclusion microthermometry of fracturing‐filling quartz crystals showed that quartz precipitation took place at temperatures of at least 140°C, from a fluid with NaCl–CaCl2–H2O composition. Melting phases are meta‐stable and suggest growth from high salinity formation water. Strontium isotopes, measured in leached host rock, indicate that, in boreholes 2 and 3, the fluid which precipitated the calcite cements and calcite‐filled fractures is most likely locally derived whereas in borehole 1, the 87Sr/86Sr ratios from the pore‐filling cements and in the elongate‐blocky calcite‐filled fracture can only be explained by mixing with externally derived fluids. The elongate‐blocky anhydrite‐filled fractures, present in boreholes 1, 3 and 4, precipitated from a mixture of locally derived pore fluids and a significant quantity of fluid with a lower, less radiogenic, 87Sr/86Sr ratio. Taking into account the structural evolution of the basin and accompanying salt tectonics, it is likely that the underlying Zechstein is a source for the less radiogenic fluids. Based on the samples in the LSB, it is probable that fibrous fracture fillings in sedimentary rocks most likely developed from locally derived pore fluids whereas elongate‐blocky fracture fillings with smooth walls developed from externally derived pore fluids.  相似文献   

17.
A polyphasic tectonic‐fluid system of a fault that involves crystalline and carbonate rocks (Hospital fault, Barcelona Plain) has been inferred from regional to thin section scale observations combined with geochemical analyses. Cathodoluminescence, microprobe analyses and stable isotopy in fracture‐related cements record the circulation of successive alternations of hydrothermal and low‐temperature meteoric fluids linked with three main regional tectonic events. The first event corresponds to the Mesozoic extension, which had two rifting stages, and it is characterized by the independent tectonic activity of two fault segments, namely southern and northern Hospital fault segments. During the Late Permian‐Middle Jurassic rifting, these segments controlled the thickness and distribution of the Triassic sediments. Also, dolomitization was produced in an early stage by Triassic seawater at shallow conditions. During increasing burial, formation of fractures and their dolomite‐related cements took place. Fault activity during the Middle Jurassic–Late Cretaceous rifting was localized in the southern segment, and it was characterized by hydrothermal brines, with temperatures over 180°C, which ascended through this fault segment precipitating quartz, chlorite, and calcite. The second event corresponds to the Paleogene compression (Chattian), which produced exhumation, folding and erosion, favouring the percolation of low‐temperature meteoric fluids which produced the calcitization of the dolostones and of the dolomite cements. The third event is linked with the Neogene extension, where three stages have been identified. During the syn‐rift stage, the southern segment of the Hospital fault grew by tip propagation. In the relay zone, hydrothermal brines with temperature around 140°C upflowed. During the late postrift, the Hospital fault acted as a unique segment and deformation occurred at shallow conditions and under a low‐temperature meteoric regime. Finally, and possibly during the Messinian compression, NW‐SE strike‐slip faults offset the Hospital fault to its current configuration.  相似文献   

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Cementum banding patterns have been used by archaeozoologists and wildlife managers for a number of decades to assess the season and age at death of mammalian populations. However, the observation and measurement of the nature of cementum banding, especially that of the final band, has proved to be difficult except under conditions of excellent preservation and advanced microscopy. The research presented here details a method for extracting luminance data from the banding patterns of cementum in order to quantify the optical properties of cementum tissue. By doing so, analysis of the relationship between cementum deposition and environmental variables is achieved. We present the results of a digital cementum luminance analysis (DCLA) on a sample of first molars from two species, Ovis aries, Soay and Capra ibex. The results indicate that significant relationships occur between seasonal temperature changes and cementum histology. Furthermore, we show that luminance values can be used to assess the geographical range of genetically similar populations. Our results demonstrate that the study of luminance is a vital tool for the quantitative study of dental cementum for both archaeological and ecological studies. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

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