Seismic Hazard of Urban Areas: A Case-Study

Lacanna, Giorgio; Deguy, Pauline Isabelle; Ripepe, Maurizio; Coli, Massimo; Paoletti, Barbara; Barducci, Sara; Tanganelli, Marco; Viti, Stefania; Stefano, Mario De

doi:10.7712/100016.2232.10806

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…For its elevation characteristics, the most affected area in 1966 was the Santa Croce neighbourhood (outside the study area), with flood depths of the order of 4-5 m. The ancient nucleus of the city (the study area) was also affected with water depths lower than 2 m, according to the elevation of historical marble plates. Although the seismic and flood risks in the city of Florence have been separately investigated in the past, they have been carried out at different spatial scales or excluded this portion of the historical city (D'Agostino et al, 2019;Arrighi et al 2018;Ripepe et al 2018Ripepe et al , 2015Matassoni et al 2017;SISMED 2016, Lacanna et al 2016.…”

Section: Earthquakes and Floods In Florencementioning

confidence: 99%

Multi-risk assessment in a historical city

et al. 2022

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Natural hazards pose a significant threat to historical cities which have an authentic and universal value for mankind. This study aims at codifying a multi-risk workflow for seismic and flood hazards, for site-scale applications in historical cities, which provides the Average Annual Loss for buildings within a coherent multi-exposure and multi-vulnerability framework. The proposed methodology includes a multi-risk correlation and joint probability analysis to identify the role of urban development in re-shaping risk components in historical contexts. The workflow is unified by exposure modelling which adopts the same assumptions and parameters. Seismic vulnerability is modelled through an empirical approach by assigning to each building a vulnerability value depending on the European Macroseismic Scale (EMS-98) and modifiers available in literature. Flood vulnerability is modelled by means of stage-damage curves developed for the study area and validated against ex-post damage claims. The method is applied to the city centre of Florence (Italy) listed as UNESCO World Heritage site since 1982. Direct multi-hazard, multi-vulnerability losses are modelled for four probabilistic scenarios. A multi-risk of 3.15 M€/year is estimated for the current situation. In case of adoption of local mitigation measures like floodproofing of basements and installation of steel tie rods, multi-risk reduces to 1.55 M€/yr. The analysis of multi-risk correlation and joint probability distribution shows that the historical evolution of the city centre, from the roman castrum followed by rebuilding in the Middle Ages, the late XIX century and the post WWII, has significantly affected multi-risk in the area. Three identified portions of the study area with a different multi-risk spatial probability distribution highlight that the urban development of the historical city influenced the flood hazard and the seismic vulnerability. The presented multi-risk workflow could be applied to other historical cities and further extended to other natural hazards.

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Section: Earthquakes and Floods In Florencementioning

confidence: 99%

Multi-risk assessment in a historical city

et al. 2022

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“…The opportunity to focus the analysis on the foundation system is related to the amount of information recently provided by the geological and geotechnical studies (Briganti et al , 2003; Coli and Rubellini, 2013; Coli et al , 2016a) developed in the area. In these past years, indeed, the city of Florence promoted a lot of research aimed at assessing the seismic safety of both regular and monumental buildings (Bartoli et al , 2015; Ripepe et al , 2015; Lacanna et al , 2016a, b, 2019; Coli et al , 2016b, 2019; Coli, 2017, 2018; Cristofaro and De Stefano, 2017).…”

Section: Introductionmentioning

confidence: 99%

The Giotto's Bell Tower at Firenze (Italy): foundation assessment

Coli¹,

Tanganelli²,

Baldi³

et al. 2021

JCHMSD

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PurposeThe paper is aimed at assessing the safety of the Giotto's Bell Tower, with special attention to its foundation system, i.e. the foundation works and soil. The tower, well known all over the world, has a squared plan, with sides of 14.45 m each, and a total height equal to 84.7 m. The structural response of the tower is assessed with reference to the gravitational load and to the expected seismic action, quantified according to the seismic hazard of the site and the foundation soil.Design/methodology/approachA simplified analysis has been performed to check the safety level of the tower to seismic actions. Special attention has been paid to quantify the horizontal actions representing the seismic loads. Such quantification, indeed, has been made both through the elastic spectrum of the tower and by performing a site response analysis on the foundation soil, represented as a one-dimensional stratification of soil layers, described on the basis of experimental investigations. After defining the loading actions, a simplified assessment of the foundation safety has been made by considering the action over foundation, the geotechnical data and the safety factor.FindingsThe findings of the paper concern the assessment of the safety of the tower's foundation system. A lot of experimental data on the foundation soil, provided by various geological investigations, have been provided and used for the assessment. Moreover, the mechanical properties of the materials used for the structure have been collected and shown in the paper.Originality/valueThe paper collects a lot of technical information regarding the Giotto's Bell Tower, both regarding its foundation soil and the constituting materials. On the basis of the collected information, a structural analysis has been made to assess the seismic safety of the tower, and the results of such assessment are provided and discussed.

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“…Many investigations [13][14][15] have been made on the soil of the Florence area, providing a detailed knowledge of the lithostratigraphic subsurface, of the lithoid substrate profile and of the geotechnical properties of its soils. The survey included 1,850 drillings and 32 downhole tests, which provided, for the case-studies vicinity, different strathigraphies, varying in the steadiness of the soil and in the consequent uppermost v s,30 .…”

Section: The Seismic Demandmentioning

confidence: 99%