Seismic Risk Assessment and Mitigation at Emergency Limit Condition of Historical Buildings along Strategic Urban Roadways. Application to the “Antiga Esquerra de L’Eixample” Neighborhood of Barcelona

ABSTRACT

This article presents a management tool for the large-scale assessment and mitigation of the seismic risk of urban systems. The research introduces a new perspective for a scientifically tackled holistic approach. The proposed methodology considers multiple objectives, from the identification of the most vulnerable buildings whose collapse may hinder the operationality of strategic urban roadways after the occurrence of an earthquake, up to the proposal of proper interventions to improve their functionality. The approach uses a performance-based approach founded on the concept of urban Emergency Limit Condition. Plotting maps of geo-referenced scenarios by means of GIS software have revealed to be extremely useful to detect the weak points of the urban network and to plan suitable strategies of seismic risk mitigation and appropriate enhancement of reliability. The proposed methodology is applied to the “Antiga Esquerra de l’Eixample” neighborhood of Barcelona that hosts the strategic route to the hospital and is characterized by high levels of seismic vulnerability of existing buildings and exposition of its high-density population.     

城中村拆迁与外来人口居住选择的影响因素研究——以上海市联明村为例

目前,上海正在大力推进城中村拆迁改造,城中村作为外来人口的聚居地,其拆迁改造势必对外来人口产生巨大影响。本文基于上海市联明村问卷调查数据,以外来人口视角,采用描述性统计和方差分析法,分析了城中村外来人口的流动特征、居住选择的变化,以及城中村拆迁对外来人口的影响。结果表明,城中村外来人口在上海有着明显的就近搬迁和在城中村之间转移的特征。房租便宜超过职住邻近成为影响外来人口居住选择的首要因素,但两者对外来人口的居住决策均起到决定性作用。外来人口对公共服务设施和居住条件考虑较少,但相较过去有所提高;同时,外来人口对血缘、地缘等社会关系的考量逐渐减少。最后,提供了相关政策启示。     

欠发达地区城市公交底线公平的空间分异特征及成因分析——以云南省为例

底线公平是欠发达地区城市公交发展的基础指标。基于底线公平理论,本文从公交服务公平性、资源配置公平性、保障公平性三个方面,建立了城市公交底线公平性测度指标体系,采用PCA模型对欠发达地区城市公交的底线公平性进行测度分析,以云南省为例获取城市公交底线公平的空间分异特征,并对其影响因素进行分析。结果表明,云南省城市公交的底线公平性总体较差,空间分布呈现“圈层”特征,全省城市公交底线公平的整体空间分异与主因子空间分异特征吻合;平均候车时间、公交站点覆盖率、公共汽电车责任事故死亡率、公交运营车辆人车比等指标是影响公交底线公平的关键指标。     

Investigation Techniques for the Seismic Response Assessment of Buildings Located in Historical Centers

ABSTRACT

It is an acknowledged fact that historical centers, given its significance from the cultural and architectural viewpoint, bring further challenges in terms of maintenance planning, survey, and safety assessment. The preparation of an adequate investigation plan and the extent of data to be collected is highly reliant on many aspects, such as the category of the architectonic asset, the importance of the heritage site, or the resources available, for example. In what regards the seismic response assessment of urban cultural heritage assets located in historical centers, the amount and detail of data also depend on this article, scale of assessment, and current state of conservation and occupation. Within this framework, this article provides an overview of the state of the art of investigation techniques currently used in survey operations, which are currently available for improving the knowledge level of urban cultural heritage assets within historical centers, as a supporting tool for the seismic response assessment of such singular assets. Finally, acknowledging the lack of accuracy when evaluating the seismic response of an asset enclosed in aggregate as an isolated structure, this article also focuses on the identification of the main particularities inherent to buildings enclosed in aggregate.     

Earthquake Risk Scenarios in Urban Areas: A Review with Applications to the Ciutat Vella District in Barcelona,Spain

ABSTRACT

The vulnerability index and capacity spectrum-based methods used to assess the expected physical damage in dwellings are revisited, and their main advantages and shortcomings are analyzed and discussed. Then, a vulnerability index-based method is used to assess the expected damage in the oldest district of Barcelona, Spain. The risk analysis is performed for earthquake scenarios defined by macroseismic intensities of V, V-VI, VI, VI-VII, and VII to design seismic emergency plans. According to the Spanish Seismic Code, the basic peak ground acceleration for a 475-year return period is 0.04 g, which corresponds to an intensity of VI. Thus, the expected physical damage is quantified and its impact on population and other quantities, such as debris and economic cost, are studied. In spite of the low-to-moderate seismic hazard in Barcelona, the results show that the risk is high, due to the high exposure and vulnerability of the built environment.     

The monumental and the miniature: imagining ‘modernity’ in Astana

This article examines the elite nation-building project in post-independence Kazakhstan through an analysis of monumental architecture and miniature models in Astana. It considers the role of the country's new capital as a modernist project, in which elite geopolitical imaginaries are multiply inscribed in the cityscape. Drawing on interdisciplinary literatures on modernity and authoritarian regime legitimation, the article considers modernity as a discursive trope employed in legitimating the Nazarbayev government, and one that has various material manifestations in the urban landscape of Astana. The research is based on fieldwork in Kazakhstan in Summer 2009, and examines architecture, monuments, and the 2009 Astana Day celebrations. Through a focus on the monumental and the miniature, it highlights their similar roles in transforming symbols of Kazakhstani independence and identity into objects of reverie outside the field of political contestation.     

Bipolar antagonism and multipolar coexistence: framing difference and shaping fear in two Caribbean cities

This article proposes a new approach to urban geographies of fear, focusing on the connection between fear and cultural understandings and representations of difference. Much of the existing work on the relationship between fear, urban space, and social difference tends to take social difference as more or less given. In this article, we argue that how differences (such as ethnic, political or class differences) are framed has strong implications for geographies of fear. The article suggests that dualistic and nondualistic framings of difference influence levels of fear and that this becomes visible in the use and perceptions of urban space, and in the built environment through the erection of physical barriers. These spatial factors, as they limit mobility and interaction, tend to reproduce the specific framing of difference. Two discursive modes of representing difference are discussed. The first, ‘bipolar antagonism’, is based on a dualist rhetoric of irreconcilable opposites. This is contrasted with ‘multipolar co-existence’, in which social categories are understood as multiple or hybrid, with flexible or fluid boundaries, and as not necessarily antagonistic. This argument is elaborated through a comparative analysis of social–cultural and spatial processes in two Caribbean cities: Kingston, Jamaica, and Paramaribo, Suriname.     

Children's nomination of friendly places in an urban neighbourhood in Shiraz,Iran

This study investigates how children conceive of and value the outdoor environment as a child-friendly one with particular reference to an urban neighbourhood in Shiraz, Iran. It utilizes Chatterjee's (2005. “Children's Friendship with Place: A Conceptual Inquiry.” Children, Youth and Environments 15 (1): 1–26) place friendship construct to find out friendly places and their attributes from children's points of view. Semi-structured interviews were conducted with 106 middle childhood children. Findings suggest that a child-friendly neighbourhood is made up of diverse places that children use to meet their different needs. However, formal and informal open spaces, private precincts, and streets in the neighbourhood afforded highest contributions to place friendship.     

A Canadian Scholar'S Views on Geography in Canada and in the USSR

There has long been controversy over the exact location of the middle segment of the great medieval trade route from the Varangians (Northmen) in the Baltic to the Greeks (Byzantium) in the Black Sea. There is no ambiguity about the northern segment, between Novgorod and the Baltic, or the southern segment, from Smolensk down the Dnieper to the Black Sea, but authors have tended to disagree about the various rivers, lakes and portages used by traders in the Russian heartland between Novgorod and Smolensk. A Russian chronicle describing a campaign led by Aleksandr Nevskiy against a Lithuanian force in 1245 sheds light on the alignment of the middle segment of the trade route. It appears that the route originally passed through Velikiye Luki in the 10th century. As this area became embroiled in clashes between warring Russian principalities, the trade route shifted eastward to the Toropets area, which became dominant by the 13th century. The existence of two additional minor routes is also noted.     

Making meaning of heritage landscapes: The politics of redevelopment in Halifax,Nova Scotia

This article investigates the production and maintenance of the heritage landscape in downtown Halifax, Nova Scotia. It argues that the unequal power relations that produced and were inscribed in the landscape historically continue to operate in the present. It does so by critically evaluating and contextualizing contestation over new high‐rise construction on the streets below Citadel Hill. Drawing on qualitative field work between 2005 and 2008, the article suggests that the meanings and values of heritage resources, such as views that served to protect the city, are not properly understood. A spatialized historical account shows how the creation of the colonial city depended upon the marginalization of groups that were other to the British settlers. A review of the establishment of the modern planning apparatus reveals a model of heritage interpretation that encourages an adversarial approach to the evaluation of proposals for new development. The characteristics and aspirations of pro‐development and pro‐heritage groups are examined. Finally, a case study of a controversial proposal to build a high‐rise building in a prominent location is presented. The article contributes to critical landscape studies by using a postcolonial approach to study the ideological underpinnings of built heritage in the Canadian context.