Yield design of dry‐stone masonry retaining structures—Comparisons with analytical,numerical, and experimental data     

A. S. Colas  J. C. Morel  D. Garnier 《国际地质力学数值与分析法杂志》2008,32(14):1817-1832

Over the past few years, there has been a steady increase in the interest in dry‐stone walling not only to preserve existing constructions but also to build new ones. Yet, dry masonry's expansion is slowed down by the lack of scientific knowledge to assess its reliability. This study aims at contributing to the construction of this scientific frame using a simplified model based on yield design and homogenization, which can be directly exploited for engineering purposes. A new analytical expression of the ultimate load is thus established. Then, the validity of the method is assessed by comparisons with limit equilibrium analysis, distinct element method, and field trials. Finally, possible improvements of the model are discussed. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

广利河口拦门沙治理的试验研究--模型设计与验证     

孙国峰  陈兆林  拾兵 《海岸工程》2004,23(2):15-18

基于广利河口水文、地形、地貌及潮汐条件,设计和制作了一个变率为8、水平比尺为400的平面模型。模型地形表面经球体梅花型布置加糙后,再现了天然潮汐及河道径流过程．其主要控制点潮位、流速、流向变化过程与原形实测资料吻合良好。  相似文献   

周期性排桩设计频段隔振原理性试验研究     

刘维宁  姜博龙  马蒙  高健 《岩土力学》2019,40(11):4138-4148

针对目前基于带隙理论开展的周期性隔振排桩性能研究偏重于解析理论分析和数值仿真计算的现状,采用原理性试验的方法,验证了周期性隔振排桩的衰减域特性。试验设计了4种工况：分别考虑了空心钢管桩和填土钢管桩两种排桩类型,以及六角晶格和正方晶格两种周期性布置方式。激振采用脉冲荷载激励,将隔振工况与无桩基本工况进行比较,对周期性排桩的振动衰减域进行了测试和分析,并与带隙理论计算的频率带隙结果进行对比。研究表明：在理论计算带隙范围内,各工况下实测衰减水平均在50%以上,最高达到98%。表明了周期排桩对特定频带的振动阻隔实际效果明显,隔振表现突出,证实了理论分析的有效性。周期排桩对水平方向的振动衰减优于竖直方向;从趋势上看,在其他条件相同时,六角晶格布置的周期排桩,其振动衰减水平优于正方晶格布置;桩内填土可有效增加六角晶格布置钢管桩的首阶带隙及衰减域宽度,有效降低正方晶格布置钢管桩的首阶带隙及衰减域起始频率。对应于试验的工程实际尺寸在0～80 Hz频段内出现多条带隙,并且最低可达20 Hz以下,这表明,基于带隙理论进行周期隔振排桩设计,在地铁列车振动环境影响的特征频段隔离或衰减中,具有广泛的应用前景。  相似文献   

地球物理场流动地磁、流动形变观测数据库设计     

周克昌  郑智江  刘文龙 《大地测量与地球动力学》2017,37(11):1201-1205

主要介绍地球物理场流动地磁观测数据库和流动形变观测数据库设计的有关方面,包括数据库内容、库和表设计、编码设计、重要技术内容说明等,给出流动地磁观测数据库和流动形变观测数据库的表清单及其E-R关系图。  相似文献   

新一代重力测量卫星核心指标分析     

肖云  刘晓刚  郭飞霄 《大地测量与地球动力学》2017,37(1):1-4

采用边界分析方法分析新一代重力测量卫星3个核心载荷--星间测距系统、非保守力测量仪和定位接收机的误差对恢复重力场的影响,提出新一代重力测量卫星的核心技术指标。分析表明,星间变率测量精度10~30 nm/s、非保守力测量精度（1~5）×10-11 m/s2、定轨精度2~3 cm时,可实现分辨率100 km、精度1~2 mGal的重力场测量。本文结论可为新一代重力测量卫星设计提供技术参考。  相似文献   

Analysis of the in‐plane response of earthen masonry infill panels partitioned by sliding joints          下载免费PDF全文

Marco Preti  Nicola Bettini  Laura Migliorati  Valentino Bolis  Andreas Stavridis  Giovanni A. Plizzari 《地震工程与结构动力学》2016,45(8):1209-1232

The vulnerability of infilled frames represents a critical issue in many regions with high seismicity around the world where infills are typically made of heavy masonry as they are used for thermal control of the buildings because of their thermal inertia. In this context, the use of earthen masonry infills can give a superior performance because of their ability to regulate thermal‐hygrometric performance of the building and sustainability of its life‐cycle. This paper presents a numerical study on the seismic behaviour of infill walls made of earthen masonry and partitioned with horizontal wooden planks that allow the relative sliding of the partitions. The combination of the deformability of earthen masonry and the sliding mechanism occurring along the wooden planks gives a high ductility capacity to the in‐plane response of the infill and, at the same time, significantly reduces its stiffness and strength, as compared with traditional solid infills made of fired clay units. As a result, the detrimental interaction with the frame and the damage in the infill when subjected to in‐plane loading can be minimized. The numerical model is validated with results from an experimental study and is used to perform a parametric analysis to examine the influence of variations in the geometry and mechanical properties of the infill walls, as well as the configuration of the sliding joints. Based on the findings of this study, design guidelines for practical applications are provided, together with simple formulation for evaluating their performance. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

A method for the direct estimation of floor acceleration spectra for elastic and inelastic MDOF structures          下载免费PDF全文

Vladimir Vukobratović  Peter Fajfar 《地震工程与结构动力学》2016,45(15):2495-2511

This paper deals with floor acceleration spectra, which are used for the seismic design and assessment of acceleration‐sensitive equipment installed in buildings. In design codes and in practice, not enough attention has been paid to the seismic resistance of such equipment. An ‘accurate’ determination of floor spectra requires a complex and quite demanding dynamic response history analysis. The purpose of the study presented in this paper is the development of a direct method for the determination of floor acceleration spectra, which enables their generation directly from the design spectrum of the structure, by taking into account the structure's dynamic properties. The method is also applicable to inelastic structures, which can greatly improve the economic aspects of equipment design. A parametric study of floor acceleration spectra for elastic and inelastic single‐degree‐of‐freedom (SDOF) and multiple‐degree‐of‐freedom structures was conducted by using (non)linear response history analysis. The equipment was modelled as an elastic single‐degree‐of‐freedom system. The proposed method was validated by comparing the results obtained with the more accurate results obtained in a parametric study. Due to its simplicity, the method is an appropriate tool for practice. In the case of inelastic structural behaviour, the method should be used in combination with the N2 method, or another appropriate method for simplified nonlinear structural analysis. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Guidelines for trust interface design for public engagement Web GIS     

Artemis Skarlatidou  Tao Cheng  Muki Haklay 《International journal of geographical information science》2013,27(8):1668-1687

Attesting to the powerful capabilities and in technology trends, many scholars envisioned the consolidation of geographic information systems (GIS) into vital tools for disseminating spatial information. GIS are presently used to inform, advise and instruct users in several contexts and to further engage citizens in decision-making processes that can impact and sustain policy development. Interaction with these applications incorporates risk and uncertainty, which have been repeatedly identified as preconditions in nurturing trust perceptions and which instigate a user's decision to rely on a system and act on the provided information. Research studies consistently demonstrated that a trust-oriented interface design can facilitate the development of more trustworthy, mainly e-commerce, systems. Trust in the Web GIS context, despite its significance, has only relatively recently received some attention. A set of human–computer interaction (HCI) user-based studies revealed some Web GIS trustee attributes that influence non-experts' trust beliefs and found that when these are problematic or absent from interface design, users form irrational trust perceptions, which amplifies the risk and may impose dangers to the user. These Web GIS trustee attributes that influence non-experts' trust perceptions are formulated here into a set of trust guidelines. These are then evaluated using the PE-Nuclear tool, a Web GIS application, to inform the public about the site selection of a nuclear waste repository in the United Kingdom. Our preliminary results indicate that the proposed trust guidelines not only support the development of rational trust perceptions that protect non-experts from inappropriate use of Web GIS technology but also contribute towards improving interaction with such applications of public interest issue.  相似文献   

A Review of “Urban Climate Change Crossroads”     

Stephanie Buechler 《The Professional geographer》2013,65(2):295-297

This article examines the former location-based social medium Brightkite, over its three-year life span, based on the concept of natural cities. The term natural cities refers to spatially clustered geographic events, such as the agglomerated patches aggregated from individual social media users’ locations. We applied the head/tail division rule to derive natural cities, based on the fact that there are far more low-density areas than high-density areas on the Earth's surface. More specifically, we generated a triangulated irregular network, made up of individual unique user locations, and then categorized small triangles (smaller than an average) as natural cities for the United States (mainland) on a monthly basis. The concept of natural cities provides a powerful means to develop new insights into the evolution of real cities, because there are virtually no data available to track the history of cities across their entire life spans and at very fine spatial and temporal scales. Therefore, natural cities can act as a good proxy of real cities, in the sense of understanding underlying interactions, at a global level, rather than of predicting cities, at an individual level. Apart from the data produced and the contributed methods, we established new insights into the structure and dynamics of natural cities; for example, the idea that natural cities evolve in nonlinear manners at both spatial and temporal dimensions.  相似文献   

Return to the Center: Culture,Public Space,and City Building in a Global Era     

《The Professional geographer》2013,65(2):278-279

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