Marco Faggella

PERFORMANCE BASED EARTHQUAKE ASSESSMENT OF AN INDUSTRIAL SILOS STRUCTURE AND RETROFIT WITH SLIDING ISOLATORS

Recent seismic events pointed out the high vulnerability of existing industrial facilities, stressing on safety and high losses inherent to interruption of economic activities and release of environmentally hazardous materials. These structures often have irregular geometry and structural configuration, are subject to aging and corrosion, and are designed without specific performance-based or seismic design criteria. Due to these inherent complexities, retrofit using friction isolators can be a viable and practical solution for performance improvements. This work presents a case study of irregular industrial storage plant structure consisting of a group of six elevated silos resting on a steel frame on one side and connected to a vaulted RC structure on the other. A computational model is built incorporating nonlinearities from the components (braces, beams, columns, etc.) and from the mitigation devices. Retrofit using friction isolators is analyzed and evaluated through linear and nonlinear dynamic analyses under a set of natural ground motions. Results show the effectiveness of the mitigation strategy in terms of performance improvement.

Seismic Assessment of R/C Building Structure through Nonlinear Probabilistic Analysis with High-performance Computing

This paper presents a probabilistic seismic demand analysis of a three dimensional R/C building model subjected to tri‐axial earthquake excitation. Realistic probability distributions are assumed for the main structural and material properties and for the ground motion Intensity Measure (IM) Sa(T1. Natural ground motions are used in the analyses to represent the inherent randomness in the earthquake ground motion time histories. Monte Carlo simulations are performed to account for the record‐to‐record variability and Tornado diagrams are used to represent the uncertainty induced in the response by the basic uncertainties in the structural properties. In order to perform a probabilistic study on three‐dimensional engineering demand parameters (EDPs), a large number of ensemble time history analyses were carried out using the TeraGrid high‐performance computing resources available at the San Diego Supercomputer Center. Early results show that for the testbed building used in this study, uncertainty in the s...

PERFORMANCE-BASED NONLINEAR RESPONSE HISTORY ANALYSIS FRAMEWORK FOR THE “PROINDUSTRY” PROJECT CASE STUDIES

Within the PROINDUSTRY project a Performance-based analysis framework is defined for seismic assessment of industrial structures, based on Nonlinear Response History Analysis (NL RHA) using in particular the Incremental Dynamic Analysis (IDA) method. This paper describes the choice of the PBEE and IDA analysis methods starting from an overview of state-of-the-art methods. The choice is analyzed in relation to: analysis goals for the selected case studies (design-based vs. risk-based), availability of databases/tools for hazard analysis and GMs selection, accuracy of criteria to scale and match GMs to a target spectrum (UHS, CMS, etc.) and treatment of record components. Three possible approaches of GMs selection are described and analyzed: (1) UHS-coherent Unscaled (Design), (2) UHScoherent GMs scaled to Sa(T1) (Risk/Loss), (3) CMS-coherent GMs scaled to Sa(T1), (Risk/Loss). Within the scopes of PROINDUSTRY, the approach (1) is proposed, as a tradeoff between simplicity of conventional PBEE design methods and probabilistic robustness for a heterogeneous portfolio of structures/facilities. M. Faggella, R. Laguardia, R. Gigliotti, F. Morelli, F. Braga, W. Salvatore.

PERFORMANCE BASED EARTHQUAKE ASSESSMENT OF AN INDUSTRIAL GAS FILTER STRUCTURE

Industrial facilities often store a large amount of hazardous material and, in case of seismic event, there is a high probability that accidental scenarios as fire, explosion, toxic or radioactive dispersion may occur. Moreover, the structural configuration of industrial facilities are often the fruit of plants and functionality requirements, that lead to strong irregularities and different load resisting systems within the same structure. This paper presents a performance-based earthquake assessment of an industrial gas filter structure, characterized by the presence of important masses placed at significant height and of different horizontal resisting systems, such as moment resisting frames, inverted V bracings and diagonal bracings. Within the framework of the PROINDUSTRY research project critical failure mechanisms of industrial structures and relevant limit states are analyzed and discussed. The structural response is computed via nonlinear finite elements analyses of the static pushover (PO) and dynamic response history type (RHA). The seismic input is defined through Probabilistic Seismic Hazard Analysis (PSHA) and a set of natural Ground Motions (GM) which are selected and scaled with different criteria with respect to the Uniform Hazard Spectrum (UHS) and the Conditional Mean Spectrum (CMS). An overview of significant aspects of the structural performance assessment is presented with respect to input definition and choice of Intensity Measures (IM), irregular structural behaviour and probabilistic treatment of key Engineering Demand Parameters (EDP) for this type of industrial structure. 4184 COMPDYN 2017 6 ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.) Rhodes Island, Greece, 15 ! 17 June 2017 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 4184-4193