SEISMIC DESIGN AND RESPONSE OF BARE AND MASONRY-INFILLED REINFORCED CONCRETE BUILDINGS. PART I: BARE STRUCTURES

Abstract

Eurocode 8 is applied for the complete design of 26 multi-storey reinforced concrete buildings to study its operationally and compare the implications of trading strength for ductility through designing the same structure for a different Ductility Class. The difference between the conventional full Capacity Design of columns in bending and the relaxed one allowed by Eurocode 8 is quantified, and the implications on the column capacities are examined. About half of the designed buildings, representative of the class of regular frames, are subjected to nonlinear dynamic response analyses to spectrum-compatible motions with intensities up to twice that of the design motion. Nonlinear modeling is very simple, but gives satisfactory agreement with available quasistatic or pseudodynamic test results on full scale structures. Results show that the three Ductility Classes of Eurocode 8 are essentially equivalent in terms of material quantities and seismic performance. Within the limitations of the nonlinear modelling, the response results suggest very satisfactory performance of structures designed to Eurocode 8, even under twice the design motion intensity. Softening of the structure due to concrete cracking and steel yielding significantly reduces the seismic force demands and contributes to the satisfactory performance, despite the increased P — 6 effects. Another important contributor to the good performance is the significant overstrength of the members considered in the analyses with their average as-built properties. Beam overstrength due to the contribution of the slab to flexural capacity is large enough to overcome the effects of the application of the relaxed Capacity Design rule to columns in bending. However, the resulting column plastic hinging does not lead to drift concentrations suggesting formation of storey-sway mechanisms.     

自然环境与云南历史文化城镇形象设计

云南复杂多样的自然环境对当地历史文化城镇的形象构成有着普遍而深刻的影响。考虑自然环境特点的云南历史文化城镇形象设计应遵循尊重和顺应自然的亲和原则,将自然与人文因素相结合的综合性原则,以及将城镇与其所在的自然环境统一考虑的整体性原则。同时要高度关注自然环境在城镇理念形象构成中的重要作用。在城镇视觉形象设计中,要注重城乡景观协调的整体效果,反映其田园山水城镇特色;注重三维景观效果;注重视觉体验的心理特点分析,组织景观层次系列;注重对城镇建筑色彩的控制。     

ECOSEMIOTICS: MAIN PRINCIPLES AND CURRENT DEVELOPMENTS

Ecosemiotics studies the role of environmental perception and conceptual categorization in the design, construction, and transformation of environmental structures. This article provides a brief review of the history of ecosemiotics, and formulates eight core principles of the ecosemiotic approach. The ecosemiotic view understands humans as capable of both prelinguistic (biosemiotic) and linguistic (cultural) modelling of their environment. Accordingly, the diversity of structures is, to a certain extent, resultant of the types of semioses partaking in their formation. Ecosemiotics could provide geography with conceptual tools to describe the role of signs and communication in the dynamics of physical environments.     

SEISMIC BEHAVIOUR OF PERIMETER AND SPATIAL STEEL FRAMES

The present study deals with the seismic performance of partial perimeter and spatial moment resisting frames (MRFs) for low-to-medium rise buildings. It seeks to establish perimeter configuration systems and hence the lack of redundancy can detrimentally affect the seismic response of framed buildings. The paper tackles this key issue by com-paring the performance of a set of perimeter and spatial MRFs, which were “consistently designed”. The starting point is the set of low-(three-storey) and medium-rise (nine-storey) perimeter frames designed within the SAC Steel Project for the Los Angeles, Seattle and Boston seismic zones. Extensive design analyses (static and multi-modal) of the perimeter frame buildings and consistent design of spatial frame systems, as an alternative to the perimeter configuration, were conducted within this analytical study. The objectives of the consistent design are two-fold, i.e. obtaining fundamental periods similar to those of the perimeter frames, i.e. same lateral stiffness under design horizon-tal loads, and supplying similar yield strength. The seismic behaviour of perimeter and spatial configuration structures was evaluated by means of push-over non-linear static analyses and inelastic dynamic analyses (non linear time histories). Comparisons be-tween analysis results were developed in a well defined framework since a clear scheme to define and evaluate relevant limit states is suggested. The failure modes, either local or global, were computed and correlated to design choices, particularly those concerning the strength requirements (column overstrength factors) and stiffness (elastic stability indexes). The inelastic response exhibited by the sample MRFs under severe ground motions was assessed in a detailed fashion. Conclusions are drawn in terms of local and global performance, namely global and inter-storey drifts, beam and column plas-tic rotations, hysteretic energy. The finding is that the seismic response of perimeter and spatial MRFs is fairly similar. Therefore, an equivalent behaviour between the two configurations can be obtained if the design is “consistent”.     

SEISMIC DESIGN AND RESPONSE OF BARE AND MASONRY-INFILLED REINFORCED CONCRETE BUILDINGS. PART II: INFILLED STRUCTURES

The effects of masonry infills on the global seismic response of reinforced concrete structures is studied through numerical analyses. Response spectra of elastic SDOF frames with nonlinear infills show that, despite their apparent stiffening effect on the system, infills reduce spectral displacements and forces mainly through their high damping in the first large post-cracking excursion. Parametric analyses on a large variety of multi-storey infilled reinforced concrete structures show that, due to the hysteretic energy dissipation in the infills, if the infilling is uniform in all storeys, drifts and structural damage are dramatically reduced, without an increase in the seismic force demands. Soft-storey effects due to the absence of infills in the bottom storey are not so important for seismic motions at the design intensity, but may be very large at higher motion intensities, if the ultimate strength of the infills amounts to a large percentage of the building weight. The Eurocode 8 provisions for designing the weak storey elements against the effects of infill irregularity are found to be quite effective, in general, for the columns, but unnecessary and often counterproductive for the beams.     

DESIGN SPACES: AGGLOMERATION AND CREATIVITY IN BRITISH DESIGN AGENCIES

Although there is a growing body of research into the cultural and creative industries, little work has focused specifically upon on the geography of design and its role in regional economies. The relative neglect of the geography of the UK design industry is surprising given recent assertions about the sector's role in national economic competitiveness; its contribution to product innovation; and its importance as an urban regeneration resource. This paper explicitly considers the extent to which existing conceptualizations of agglomeration and creativity provide insights into the realm of design. Our discussion reflects upon recent surveys of the design sector and analyses current design organization membership data, both of which reveal an overwhelming concentration of design activities in London and the South East. Our analysis of the strategies, organization and practices of agencies in London reveals that a number of the key features associated with cultural industries in general are significantly less discernible within design.     

体验经济时代下旅游项目设计与实证研究

体验性旅游项目设计包括纵向深度设计和横向整合设计。旅游项目纵向设计是深度挖掘单项旅游资源(或吸引物)潜力,实现单项旅游项目经济价值最大化。并就感官指数,时间指数,复杂指数,环节指数,互动指数,交叉指数,遗憾指数,惯性指数8个因子和23个指标提出其定量评价指标体系。旅游项目横向设计,即旅游线路设计,是在纵向设计基础上,对旅游项目在空间上、类型上进行全方位横向整合设计。并以贡嘎山海螺沟风景名胜区为例,在纵向与横向两度空间进行旅游项目体验性设计,为景区体验性旅游项目设计提供理论、方法和范例。     

双休日休闲旅游市场特征及产品开发

本文对双休日休闲旅游性质及其市场特征进行了分析,认为这一旅游形式在当前我国国内旅游发展中占有重要地位,其旅游动机回归自然趋向明显,市场具有范围有限、组织化差、基本消费为主、淡旺季不明显等特征,最后,提出了双休日休闲旅游产品开发的主要方向。     

SEISMIC DESIGN AND ANALYSIS OF A KNEE BRACED FRAME BUILDING

A five-storey steel frame incorporating dissipative knee elements is designed using the Eurocode 8 pushover analysis method. The non-linear analysis makes use of a novel knee element model capable of accurately simulating the bending and shear behaviour observed in full-scale tests. The performance of the structure is assessed using non-linear time-history analysis. This shows that the knee elements can be designed to yield under small earthquakes or early in a strong one (maximising their energy dissipation) while still being able to withstand a large event without collapse. Knee elements thus have the potential to give excellent seismic performance in steel framed structures. The time history analysis results are compared to those obtained with the three different pushover analysis methods (Eurocode 8, FEMA 356 and ATC 40). The FEMA 356 method, which includes a more accurate representation of the structure's significant post-yield stiffness, gave the closest agreement with the time history analyses, while the Eurocode 8 method gave rather conservative results and the ATC 40 method appears non-conservative for this type of structure.     

美国乡土景观研究理论与实践——《发现乡土景观》导读

《发现乡土景观》①一书是美国"乡土景观之父"杰克逊关于文化景观研究的力作。杰克逊建立了美国乡土景观研究的理论框架:两种理想景观--政治景观和栖居景观,以及三种景观原型--景观一、景观二、景观三。在此框架下,探讨当代美国乡土景观的典型要素:平面空间、乡村小镇、乡土建筑、可移动房屋、石材与木材、科技风格、新型公园、新田园。该书提出的乡土景观研究方法论、乡土景观内涵的理解等,对当代中国景观研究和景观设计具有重要参考意义。     

兰州黄河文化园规划构思与项目创意

黄河文化园是规划开发中的黄河兰州市区段40km风情旅游线上一座融地理、历史、民俗于一体的文化主题公园。在提出3条规划思路的基础上,本文将该园划分为"文明之光"、"地理揽胜"、"文物瑰宝"、"民俗采风"、"古街余韵"等5大景区,相应设计了若干景点和诸多观赏性、参与性和娱乐性颇强的旅游活动项目,还对该园进行了旅游形象策划,并在绿化规划方面有独到的见解和创新。     

城市旅游空间规划布局及其生态环境的优化与调控研究

城市旅游发展所带来的主要病症之一是城市旅游生态环境的破坏。笔认为主要原因之一在于城市旅游空间发展的无序、空间布局的不合理及对城市旅游资源的过度开发。本对如何正确运用城市空间发展战略及正确使用城市旅游承载力优化与调控城市旅游生态环境作了初步探讨。     

CHORA IN CURRENT GEOGRAPHICAL THOUGHT: PLACES OF CO‐DESIGN AND RE‐MEMBERING

Reading places is integrally linked to geographical studies. One of the oldest Western formulations of place is chora, which was introduced in Plato's Timaeus and has thereafter contributed to a rich tradition of interpretations. The geographical interest in chora has gradually increased as it has proven its value in making sense of the flowing conditions of contemporary social change. The gradual turn towards chora is also due to intense methodological rethinking in geography during recent decades. This article discusses the latest formulations of the geographies of chora, and focuses especially on the interpretations inspired by Jacques Derrida and Julia Kristeva. Their formulations of chora, including succeeding critiques, have encouraged us to rethink places of co‐design and re‐membering as illustrations of the paradoxes of chora as a ‘place in‐between’.     

COMPETING BY DESIGN, SPECIALIZATION AND CUSTOMIZATION: MANUFACTURING LOCKS IN THE WEST MIDLANDS (UK)

The past thirty years have seen major shifts and improvements in manufacturing productivity, bringing greater output but fewer jobs. As a result, manufacturing is now less visible in "post-industrial" societies. Nevertheless, manufacturing still matters in developed market economies but our understanding of manufacturing has failed to evolve with developments in the management and organization of production processes. This paper explores the lock industry in the West Midlands (UK), a traditional low-tech manufacturing sector. West Midlands lock companies that produced standardized, mass-produced products have experienced intensive competition from low-cost producers. Many of these firms have downsized their operations in the UK. Nevertheless, this is only one response to intensified competition. Lock firms located in the West Midlands are unable to compete on price and have shifted away from the production of mass-produced locks to concentrate on high value-added niche markets. The firms have developed inimitability strategies based around design, expertise, specialization, customization and nearness to market that assist them in maintaining their revenue and profit streams. Niche manufacturers have been far less susceptible and relatively immune to foreign competition and they continue to diversify product ranges by targeting specialist end-users. The emphasis is on producing high-quality locks in small batches that can be produced just-in-time to meet customers' requirements. The continued survival of these lock firms is based upon a strategy that includes the development of product-based competitive advantage combined with locational advantage and supported by efficient, responsive and customer-focused manufacturing processes.     

SEISMIC HAZARD ASSESSMENT OF UNITED ARAB EMIRATES AND ITS SURROUNDINGS

This paper presents the seismic hazard assessment and seismic zoning of the United Arab Emirates (UAE) and its surroundings based on the probabilistic approach. The area that has been studied lies between 50°E-60°E and 20°N-30°N and spans several Gulf countries. First, the tectonics of the area and its surroundings is reviewed. An updated catalogue, containing both historical and instrumental events is used. Seismic source regions are modelled and relationships between earthquake magnitude and earthquake frequency is established. A modified attenuation relation for Zagros region is adopted. Seismic hazard assessment is then carried out for 20 km interval grid points. Seismic hazard maps of the studied area based on probable Peak Ground Acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100 and 200 years are shown. A seismic zone map is also shown for a 475-year return period. Although the results of the seismic hazard assessment indicated that UAE has moderate to low seismic hazard levels, nevertheless high seismic activities in the northern part of UAE warrant attention. The northern Emirates region is the most seismically active part of UAE. The PGA on bedrock in this region ranges between 0.22 g for a return period of 475 years to 0.38 g for a return period of 1900 years. This magnitude of PGA, together with amplification from local site effect, can cause structural damage to key structures and lifeline systems.     

旅游口号设计框架构建及其偏离分析:基于衰减器作用视角

作为建立品牌认知、创建品牌资产和投射品牌形象的重要手段,旅游口号在"目的地竞争战"中发挥了重要作用。立足于"衰减器"作用机理,构建旅游口号设计规则框架。同时,根据旅游口号评价指标与设计规则的分歧倾向比例来定义偏离级次,实证分析不同地域尺度的旅游口号的偏离程度和偏离分布差异。研究结论显示：①衰减器的内部作用过程包括特征抽取和口号衰减两个阶段;②旅游口号的偏离情况具有地域尺度差异性。省域旅游口号的总偏离程度最高,景域旅游口号的偏离分布差异性最明显,而市域旅游口号和我国旅游口号的偏离分布一致。     

DAMAGE AND DUCTILITY DEMAND SPECTRA ASSESSMENT OF HYSTERETIC DEGRADING SYSTEMS SUBJECT TO STOCHASTIC SEISMIC LOADS

Damage phenomena observed in structures subject to intense seismic events are the result of stiffness and strength degradation. This paper studies the damage assessment of hysteretic degrading structures described by means of the Bouc-Wen model, modified to represent the mechanical degradation induced by severe earthquakes. In order to consider randomness of seismic action, the analysis is performed by adopting a stochastic approach and the Park and Ang damage functional is also evaluated in stochastic way. A parametric analysis is carried out with the aim to analyse the effect of mechanical characteristics and measure parameters of earthquake intensity on seismic response and damage level. Damage spectra are finally obtained and they are used to develop, on the basis of the Performance Based Seismic Design, ductility demand spectra.     

治理术与地理学:研究述评与展望

治理术作为福柯后期研究的一个重要概念具有丰富的内涵,已被广泛用于西方地理学的研究。本文在福柯的著作和西方相关文献的基础上,梳理了治理术的概念,归纳了西方地理学对治理术的主要应用。福柯的治理术主要包含治理技术和治理理性两个向度;治理术的分析框架以生命政治、计算和治理目的为支柱;与这一分析框架相对应,西方地理学对治理术的应用集中在以下三个话题:族群与生命政治,领土与计算,认知/空间合理性和城市管治。治理术的相关概念和方法在解释中国的单位制度和户口制度、阶级斗争和空间非均衡发展、分税制和城市规划及加强中国地理学的理论化和学术贡献上具有重要意义。     

油气地缘经济与中国油气安全

本文从地缘政治观念向地缘经济观念发展的观点出发,通过对全球油气中心随时空转移和变化的分析,着重阐述了冷战以后全球形成的"石油心脏地带"和"内需求月形地带"及"外需求月形地块"的油气地缘经济格局以及有关国家围绕争夺中亚油气资源和跨国运输通道构成的内外两个三角之间的油气地缘战略竞赛,在此基础上讨论了中国油气安全所面临的处境与应采取的对策。     

TEXTS AND TRADITIONS IN CHINESE AND COMPARATIVE PHILOSOPHY

This article considers Quentin Skinner's critique and methodology in his seminal essay “Meaning and Understanding in the History of Ideas” vis-à-vis the current methodological debates in Chinese and comparative philosophy. It surveys the different ways in which philosophers who work with ancient Chinese texts in those related fields deal with the tension between textual contexts and autonomy and how some of the errors criticized by Skinner under the mythology of coherence, mythology of doctrines, mythology of parochialism, and mythology of prolepsis might apply to those fields. It argues that Skinner's insistence that understanding a text requires recovering its author's intended meaning by studying its linguistic context has limited application to Chinese and comparative philosophy because those fields’ most important texts are not best understood as means of communication by specific historical authors with intended messages to convey to readers. These texts are instead the means by which Chinese traditions perpetuate their respective beliefs and practices. Instead of being circumscribed by authorial intent, the meanings of traditional texts are dynamic and co-created in the process of producing, reproducing, and consuming texts as well as in the evolution of practices that also constitute each tradition. The meanings received by the audience are never exactly what authors or transmitters intended but have been transformed by each audience's own concerns and interests, even if the audience attempts to grasp what the former intended. Using the Five Classics and the Analects as examples, this article illustrates how such texts’ purposes to teach and perpetuate the practices that constitute a way of life determine their meanings. Understanding is not merely cognitive but practical as well. The meanings of such texts are not static but dynamic as traditions evolve. The debates about methods of reading and interpreting ancient Chinese texts are also debates about the nature of Chinese traditions and struggles over their futures.