Seismic Fragility Functions via Nonlinear Response History Analysis

Bakalis, Konstantinos; Vamvatsikos, Dimitrios

doi:10.1061/(asce)st.1943-541x.0002141

Cited by 127 publications

(77 citation statements)

References 47 publications

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“…The EDA rule principle was employed as the basis of a modified version that can be used to calculate similar results to those obtained via NLDA. This simplified procedure can be used to estimate, for instance, fragility curves via cloud analysis [11] without the need to perform NLDAs. Thus, the fragility curves for several damage state thresholds, related to MIDR 0.005, 0.01, 0.015 and 0.02, for the reinforced concrete six-story building shown in Figure 10a will be obtained based on the NLDA and the modified EDA.…”

Section: Discussionmentioning

confidence: 99%

On the Equal Displacement Approximation for Mid-Rise Reinforced Concrete Buildings

Alzate¹,

Pujades²,

González-Drigo³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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The equal displacement approximation is a well-known procedure for estimating the non-linear behavior of structures subjected to earthquake ground motions. This procedure plays a significant role in current seismic design, since it constitutes the basic assumption for defining strength reduction factors. In this paper, calculation of the performance point based on this rule is used to estimate engineering demand parameters such as those obtained by advanced probabilistic non-linear dynamic analysis, NLDA. We present a modification to the classic approach, to improve the predictability of the equal displacement rule. Uncertainties in seismic action and structural properties are considered. Mid-rise reinforced concrete buildings will be used as a testbed. To obtain a representative sample of buildings for statistical analysis, we describe the development through implementation of a numerical tool for calculating probabilistic NLDA. This tool, which is expected to evolve into interoperable software for assessing the seismic risk of structures, is developed within the framework of the KaIROS project. The results presented in this paper could be used to estimate the seismic risk of structures in a very simplified manner.

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Section: Discussionmentioning

confidence: 99%

On the Equal Displacement Approximation for Mid-Rise Reinforced Concrete Buildings

Alzate¹,

Pujades²,

González-Drigo³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…Since the distribution of the number of stories is known, other properties related to the number of spans, N sp , the story height, H st , and the span length, S l , are considered random variables. Thus, N sp follows a uniform, discrete distribution in the interval [3,6]. H st is distributed uniformly in the interval [2.8, 3.2] m. S l is distributed uniformly in the interval [4,6] m. These ranges are typical in the RC buildings in Barcelona and they were estimated after analyzing several blueprints and visiting some buildings in the district.…”

Section: Building To Building Variationmentioning

confidence: 99%

“…The numerical tools developed in Vargas-Alzate et al (2019) [2] were intended to estimate seismic damage via cloud analysis. However, in the present study, these tools have been adapted to estimate expected seismic damage based on stripe analysis [3]. To achieve this correctly, it is fundamental to have enough information to characterize the seismic hazard and the exposure.…”

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confidence: 99%

Seismic Risk Assessment Using Stochastic Nonlinear Models

et al. 2020

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The basic input when seismic risk is estimated in urban environments is the expected physical damage level of buildings. The vulnerability index and capacity spectrum-based methods are the tools that have been used most to estimate the probability of occurrence of this important variable. Although both methods provide adequate estimates, they involve simplifications that are no longer necessary, given the current capacity of computers. In this study, an advanced method is developed that avoids many of these simplifications. The method starts from current state-of-the-art approaches, but it incorporates non-linear dynamic analysis and a probabilistic focus. Thus, the method considers not only the nonlinear dynamic response of the structures, modeled as multi degree of freedom systems (MDoF), but also uncertainties related to the loads, the geometry of the buildings, the mechanical properties of the materials and the seismic action. Once the method has been developed, the buildings are subjected to earthquake records that are selected and scaled according to the seismic hazard of the site and considering the probabilistic nature of the seismic actions. The practical applications of the method are illustrated with a case study: framed reinforced concrete buildings that are typical of an important district, the Eixample, in Barcelona (Spain). The building typology and the district were chosen because the seismic risk in Barcelona has been thoroughly studied, so detailed information about buildings' features, seismic hazard and expected risk is available. Hence, the current results can be compared with those obtained using simpler, less sophisticated methods. The main aspects of the method are presented and discussed first. Then, the case study is described and the results obtained with the capacity spectrum method are compared with the results using the approach presented here. The results at hand show reasonably good agreement with previous seismic damage and risk scenarios in Barcelona, but the new method provides richer, more detailed, more reliable information. This is particularly useful for seismic risk reduction, prevention and management, to move towards more resilient, sustainable cities.Sustainability 2020, 12, 1308 2 of 21 software useful for estimating the stochastic response of multi degree of freedom systems (MDoF) systems by considering uncertainties in the seismic hazard and in the main features of the structures. Uncertainties were considered in relation to the geometry of the structure, the mechanical properties of the materials and the seismic action, amongst many other variables. In that study, thousands of non-linear dynamic analyses (NLDA) were executed using thousands of structural models and earthquake records. The procedure for combining the structural models and the earthquake records was based on the Latin hypercube and Monte Carlo sampling methods.From the NLDA results presented in Vargas-Alzate et al. 2019 [2], a simplified methodology was proposed to estimate maximum inter-story drifts ...

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“…In other words, this function provides as result some fragility curves, which can be obtained from the probability of violating some limit states, to which some given values of IM are associated. As reported in [27], fragility curves are ruled by mathematical relationships, like the one in equation 4:…”

Section: Seismic Fragility Of Existing Rc Buildingsmentioning

confidence: 99%

Influence of Infill Panels and Floor System in the Fragility Analysis of Existing Rc Buildings: A Case Study

Ruggieri¹,

Porco²,

Fiore³

et al. 2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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In the last few years, the study of the seismic fragility of existing Reinforced Concrete (RC) buildings has been the object of a wide interest within the scientific community, especially after the experiences provided by recent hazardous events, which have shown the vulnerability of the existing RC building stock. The recent studies about this topic have shown that the probabilistic approach of Performance Based Earthquake Engineering (PBEE) is the most suitable methodology for taking into account the different sources of uncertainty in fragility analysis, considering both the nature of the seismic demand and the problems related to the incomplete knowledge. For an accurate probabilistic seismic fragility estimation, a fundamental aspect is to consider the contribution of all the elements that constitute the building system, such as the secondary structural (floor system) and non-structural elements (infill panels). In this paper, the focus is aimed on the investigation of the role of secondary and non-structural elements in the evaluation of fragility curves of existing RC buildings. In particular, a real case study, representative of the typical existing school buildings of the Southern Italy, is analysed and discussed.

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Seismic Fragility Functions via Nonlinear Response History Analysis

Cited by 127 publications

References 47 publications

On the Equal Displacement Approximation for Mid-Rise Reinforced Concrete Buildings

On the Equal Displacement Approximation for Mid-Rise Reinforced Concrete Buildings

Seismic Risk Assessment Using Stochastic Nonlinear Models

Influence of Infill Panels and Floor System in the Fragility Analysis of Existing Rc Buildings: A Case Study

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