An approach for analysis of urban morphology: methods to derive morphological properties of city blocks by using an urban landscape model and their interpretations

Yoshida, Hiroyuki; Omae, Manabu

doi:10.1016/j.compenvurbsys.2004.05.008

Cited by 77 publications

(30 citation statements)

References 5 publications

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“…1. While shapes, sizes and densities of buildings seem to be characteristics of socioeconomic blocks, for example, residential, commercial or business districts (Yoshida & Omae 2005), a city-taxonomy has been proposed by Figueiredo & Amorim (2007) based upon the likeness of urban arrangements to a grid. Those observations suggest the possibility to idealize some city districts as the periodic distribution of similar structures.…”

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confidence: 99%

Site-city interaction: theoretical, numerical and experimental crossed-analysis

Schwan¹,

Boutin

Padrón

et al. 2016

Geophys. J. Int.

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S U M M A R YThe collective excitation of city structures by a seismic wavefield and the subsequent multiple Structure-Soil-Structure Interactions (SSSIs) between the buildings are usually disregarded in conventional seismology and earthquake engineering practice. The objective here is to qualify and quantify these complex multiple SSSIs through the design of an elementary study case, which serves as a benchmark for theoretical, numerical and experimental crossed-analysis. The experimental specimen consists of an idealized site-city setup with up to 37 anisotropic resonant structures arranged at the top surface of an elastic layer and in co-resonance with it. The experimental data from shaking table measurements is compared with the theoretical and numerical results provided respectively by an equivalent city-impedance model derived analytically from homogenization in the long-wavelength approximation and a model based on boundary elements. The signatures of the site-city interactions are identified in the frequency, time and space domain, and in particular consist of a frequency-dependent free/rigid switch in the surface condition at the city resonance, beatings in the records and the depolarization of the wavefield. A parametric study on the city density shows that multiple SSSIs among the city structures (five are sufficient) can have significant effects on both the seismic response of its implantation site and that of the buildings. Key parameters are provided to assess site-city interactions in the low seismic frequency range: They involve the mass and rigidity of the city compared to those of the soil and the damping of the building.Key words: Earthquake dynamics; Earthquake ground motions; Body waves; Seismic anisotropy; Site effects; Wave propagation. I N T RO D U C T I O NUrban and industrial areas require a particular attention in seismic analysis due to the concentrations of population, real estates, strategic public services and human activities having a large socioeconomical impact. However, the presence of the city is usually disregarded in conventional methods applied in seismology and earthquake engineering: The ground motion is supposed to result from the seismic source and substratum properties only, for example, Bonnefoy-Claudet et al. (2008), while the response of a structure to the ground motion is studied independently from the surrounding buildings, for example, Jennings & Bielak (1973). These standard approaches omit the effects of multiple soil-structures dynamic interactions on the seismic field and the buildings' response.While these approximations are reasonable in most cases, they are questionable in urban areas, where high-rise buildings, similar in height and design, are built closely from one another. Neighbouring buildings can exchange significant amounts of energy with each other, and form, with the soil, a fully coupled dynamic system that should be treated as a whole. The problem of mutual interactions between two buildings have been formulated initially by Luco & Contesse (19...

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mentioning

confidence: 99%

Site-city interaction: theoretical, numerical and experimental crossed-analysis

Schwan¹,

Boutin

Padrón

et al. 2016

Geophys. J. Int.

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“…The problem is that some of the aforementioned variables are hard to calculate for realistic and complex spatial models, which makes it impossible for application in existing urban environment evaluation. In a study to analyze urban morphology in Tokyo, Yoshida and Omae [53] chose a 2 km × 2 km area as their study site. City blocks were used by the authors as spatial units for morphological variable calculation.…”

Section: Built Form Descriptorsmentioning

confidence: 99%

The Impact of Urban Design Descriptors on Outdoor Thermal Environment: A Literature Review

et al. 2017

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This paper presents a literature review on urban design indicators addressing the impact of urban geometry and vegetation on the outdoor thermal environment at the pedestrian level, as urban geometry and vegetation have been regarded as the most influential urban design factors that affect outdoor microclimate. The thermal balance concept is first introduced to elaborate how each component of energy fluxes is affected by the urban built environment, which helps to explore the underlying thermophysical mechanisms of how urban design modifies the outdoor thermal environment. The literature on numerous urban design descriptors addressing urban geometric characteristics is categorized into five groups in this paper according to the design features that the parameters entail, including land use intensity, building form, canyon geometry, space enclosure and descriptive characteristics. The literature on urban vegetation descriptors is reviewed together, followed by the combined effect of urban geometry and vegetation. This paper identifies a series of important urban design parameters and shows that the impact of design parameters on thermal environment varies with time, season, local climate and urban contexts. Contradictory impacts often occur between daytime and nighttime, or different seasons, which requests trade-offs to be achieved when proposing design strategies.

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“…For more details, please consult Baltsavias [30]. Data derived from LiDAR technology can be used, for instance, on the extraction of valuable and useful urban indicators such as the assessment of the solar potential of roofs [31], the estimation of urban tree crown volume [32] or the analysis of the urban form [33].…”

Section: Introductionmentioning

confidence: 99%