Large-Scale Seismic Vulnerability Assessment Method for Urban Centres. An Application to the City of Florence

2014 ◽  
Vol 628 ◽  
pp. 49-54 ◽  
Author(s):  
Maurizio Ripepe ◽  
Giorgio Lacanna ◽  
Pauline Deguy ◽  
Mario de Stefano ◽  
Valentina Mariani ◽  
...  

The seismic vulnerability assessment of a building requires a comprehensive knowledge of both building structural features and soils geophysical parameters. To achieve a vulnerability assessment at the urban scale a large amount of data would be necessary, with a consequent involvement of time and economical resources. The aim of this paper is hence to propose a simplified procedure to evaluate the seismic vulnerability of urban centres and possible seismic damage scenarios in order to identify critical areas and/or building typologies to plan future actions of seismic risk mitigation and prevention. The procedure is applied to the outstanding case study of the city of Florence. The research is based on the definition of major building typologies related to construction periods and type of the structural system (masonry or reinforced concrete), the identification of a set of sample buildings, the analysis of the dynamic behaviour and the evaluation of a vulnerability index with an expeditious approach. The obtained results allow to define potential vulnerability and post-event damage scenarios related to the expected levels of peak ground acceleration.

2020 ◽  
Vol 12 (3) ◽  
pp. 1276 ◽  
Author(s):  
L. Gerardo F. Salazar ◽  
Tiago Miguel Ferreira

Seismic risk is determined by the sum of multiple components produced by a certain seismic intensity, being represented by the seismic hazard, the structural vulnerability and the exposure of assets at a specified zone. Most of the methods and strategies applied to evaluate the vulnerability of historic constructions are specialized in buildings with higher importance, either public or private, by relegating ordinary dwellings to a second plane. On account of this, this paper aims to present a seismic vulnerability assessment, considering a limited urban area of the Historic Downtown of Mexico City (La Merced Neighborhood), thus showing the analysis of 166 historic buildings. The seismic vulnerability assessment of the area was performed resorting to a simplified seismic vulnerability assessment method, composed of both qualitative and quantitative parameters. To better manage and analyze the human and economic exposure, the results were integrated into a Geographic Information System (GIS) tool, which allowed to map vulnerability and damage scenarios for different earthquake intensities.


2020 ◽  
Vol 10 (18) ◽  
pp. 6411 ◽  
Author(s):  
Ehsan Harirchian ◽  
Kirti Jadhav ◽  
Kifaytullah Mohammad ◽  
Seyed Ehsan Aghakouchaki Hosseini ◽  
Tom Lahmer

Recently, the demand for residence and usage of urban infrastructure has been increased, thereby resulting in the elevation of risk levels of human lives over natural calamities. The occupancy demand has rapidly increased the construction rate, whereas the inadequate design of structures prone to more vulnerability. Buildings constructed before the development of seismic codes have an additional susceptibility to earthquake vibrations. The structural collapse causes an economic loss as well as setbacks for human lives. An application of different theoretical methods to analyze the structural behavior is expensive and time-consuming. Therefore, introducing a rapid vulnerability assessment method to check structural performances is necessary for future developments. The process, as mentioned earlier, is known as Rapid Visual Screening (RVS). This technique has been generated to identify, inventory, and screen structures that are potentially hazardous. Sometimes, poor construction quality does not provide some of the required parameters; in this case, the RVS process turns into a tedious scenario. Hence, to tackle such a situation, multiple-criteria decision-making (MCDM) methods for the seismic vulnerability assessment opens a new gateway. The different parameters required by RVS can be taken in MCDM. MCDM evaluates multiple conflicting criteria in decision making in several fields. This paper has aimed to bridge the gap between RVS and MCDM. Furthermore, to define the correlation between these techniques, implementation of the methodologies from Indian, Turkish, and Federal Emergency Management Agency (FEMA) codes has been done. The effects of seismic vulnerability of structures have been observed and compared.


2020 ◽  
Vol 12 (18) ◽  
pp. 7787 ◽  
Author(s):  
Jihye Han ◽  
Jinsoo Kim ◽  
Soyoung Park ◽  
Sanghun Son ◽  
Minji Ryu

The main purpose of this study was to compare the prediction accuracies of various seismic vulnerability assessment and mapping methods. We applied the frequency ratio (FR), decision tree (DT), and random forest (RF) methods to seismic data for Gyeongju, South Korea. A magnitude 5.8 earthquake occurred in Gyeongju on 12 September 2016. Buildings damaged during the earthquake were used as dependent variables, and 18 sub-indicators related to seismic vulnerability were used as independent variables. Seismic data were used to construct a model for each method, and the models’ results and prediction accuracies were validated using receiver operating characteristic (ROC) curves. The success rates of the FR, DT, and RF models were 0.661, 0.899, and 1.000, and their prediction rates were 0.655, 0.851, and 0.949, respectively. The importance of each indicator was determined, and the peak ground acceleration (PGA) and distance to epicenter were found to have the greatest impact on seismic vulnerability in the DT and RF models. The constructed models were applied to all buildings in Gyeongju to derive prediction values, which were then normalized to between 0 and 1, and then divided into five classes at equal intervals to create seismic vulnerability maps. An analysis of the class distribution of building damage in each of the 23 administrative districts showed that district 15 (Wolseong) was the most vulnerable area and districts 2 (Gangdong), 18 (Yangbuk), and 23 (Yangnam) were the safest areas.


2020 ◽  
Vol 194 ◽  
pp. 01005
Author(s):  
Weiwei Sun ◽  
Dina D’Ayala ◽  
Jinxing Fu ◽  
Wentao Gu ◽  
Jun Feng

This paper investigates the seismic performance of a high-rise molten-salt solar tower by finite element modelling. The integrated and separated models for solar tower based on the concrete damage plastic model are validated by matching the behaviour of similar reinforced concrete chimney specimens. The modal analysis demonstrates the first four modes of the solar tower are translational vibration. Seismic simulations are developed through the incremental dynamic analysis. The most disadvantageous position of the tower is all concentrated in the opening section under multidirectional seismic excitations. The top displacement of the tower under bidirectional and three-directional earthquake actions is larger than that under unidirectional earthquake actions. The results of the seismic vulnerability assessment show that when the PGA equals to 0.035g, the tower will be intact; when the PGA equals to 0.1g (design peak ground acceleration), the probability of the moderate damage state is within 1.5%; when the PGA equals to 0.22g (maximum considered earthquake), the probability of the destruction state is below 0.7%. The seismic partitioned fragility analysis of the tower under multidirectional earthquake excitations illustrates that there are two peaks in the vulnerability surfaces. The anti-collapse analysis indicates the tower has a good seismic performance under multidirectional seismic excitations.


Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.


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