1,721,044 research outputs found
Seismic Risk Assessment of Non-Structural Components in Hazardous Facilities Through a Novel ANN-Based Technique
No full textSeismic events pose a significant threat to industrial facilities, and the risk assessment of non-structural components (NSCs) within these structures is paramount for ensuring the safety and functionality of critical infrastructure. This paper presents a novel approach utilizing machine learning techniques to enhance the seismic risk assessment of NSCs in industrial facilities. The proposed methodology integrates data from multiple sources, including seismic records, structural characteristics, and NSC vulnerability parameters, to develop predictive models for evaluating the vulnerability and potential damage to non-structural components during seismic events. The study starts from a dataset generated by using a numerical effective model subjected to a set of natural records. The advantages of using an efficient model that manages to be both reliable and computationally efficient are highlighted in this paper. With this in mind, the steps to be followed to create an efficient numerical model are herein illustrated. Subsequently, an artificial neural network machine learning algorithm is adopted for training and evaluation. The latter is used for predicting the likelihood of damage to NSCs based on factors such as the intensity and duration of ground motion, the NSC's location within the structure, and its inherent vulnerability characteristics. Results are compared with traditional methods. The outcomes indicate the effectiveness of machine learning in improving the accuracy and efficiency of seismic risk assessment for NSCs in industrial plant. The research contributes to the field of seismic risk assessment by demonstrating the potential of machine learning combined with an efficient numerical model in providing more accurate and timely predictions for the vulnerability of nonstructural components, thereby aiding in the development of targeted mitigation strategies and emergency response plans. This paper serves as a foundational step towards a data-driven approach to seismic risk assessment for non-structural industrial components, ultimately reducing the economic and human losses associated with seismic events
An innovative framework for risk assessment of non-structural components for industrial plants
No full textNa-Tech events (Natural Hazard Triggering Technological Disasters) are industrial accidents triggered by natural events such as hurricanes, floods, earthquakes, tsunami, etc. In the recent decades, various analytical approaches for the performance-based earthquake engineering (PBEE) have been developed. The most famous approach has been provided by the Pacific Earthquake Engineering Research (PEER) Center, which consists of four stages: hazard analysis, demand analysis, damage analysis, and risk assessment. The accuracy of this method in the case of complex critical infrastructure, such as nuclear and non-nuclear industrial plants, is still under investigation. Specifically for these critical structures, it is necessary to define different Limit States and appropriate Engineering Demand Parameters (EDP), especially in presence of critical Non-Structural Components (NSC), whose damage can have serious consequences. Furthermore, because of the narrow distribution of frequencies in the demand of NSC, the selection of ground motion records for fragility analysis is also a critical aspect. Consequently, the aim of the proposed study is to investigate the suitability of the PBEE approach in presence of NSCs and their dynamic interaction with the primary structure. On these premises, a comprehensive shake table test campaign was carried out with the aim to investigate the seismic behaviour of two structural configurations of a representative industrial multi-storey frame equipped with process NSCs. The main limit states for NCSs are identified and the related fragility curves are built, in a PBEE perspective, based on both experimental results and finite element model (FEM) simulations. For this purpose, an innovative algorithm for ground accelerogram selection is used. Finally, the mean annual frequency (MAF) of exceedance of the experimentally identified limit states for relevant NSCs is carried out
Inverse identification of buffeting and self-excited wind loads on the hardanger bridge from acceleration data
No full textThe traditional wind load assessment for long-span bridges rely on assumed models for the wind field and aerodynamic coefficients from wind tunnel tests, which usually introduces some uncertainties. It is therefore desired to develop tools that can utilize full-scale vibration response data from existing bridges in order to study the wind loading in detail for in-situ conditions. This paper presents a novel case study of inverse identification of dynamic wind loads on the 1310 m long Hardanger bridge, a suspension bridge equipped with a network of accelerometers. The identification method used is an extented Kalman-type filter for joint input, state, and parameter estimation. A system model considering the still-air modes in addition to a quasi-steady submodel for the self-excited forces of the bridge is presente. The coefficients for self-excited lift and pitching moment are considered unknown and are jointly estimated with the buffeting forces.Dynamics of StructuresOffshore Engineerin
Computation of axisymmetric vibration transmission using a well-conditioned system for elastic layers over a half–space
Full text linkIn the context of range-independent solid media, we propose a well-conditioned dynamic stiffness matrix for an elastic layer sitting over an elastic half-space. This formulation overcomes the well-known problem of numerical ill-conditioning when solving the system of equations for deep-layered strata. The methodology involves the exact solutions of transformed ordinary differential equations in the wavenumber domain, namely a projection method based on the transformed equations with respect to the depth coordinate. By re-arranging the transformed equations, the solutions remain numerically well-conditioned for all layer depths. The inverse transforms are achieved with a numerical quadrature method and the results presented include actual displacement fields in the near-field of the load in plane-strain and three-dimensional axisymmetric cases. Verification against finite element method (FEM) calculations demonstrates the performance and complexity of the two approaches
Dynamic Response of a Rigid Slab Supported by Four Rigid Cylindrical Rocking and Wobbling Columns
No full textOn the vibration attenuation performance of a geometrically nonlinear device mounted to a multi-storey structure
No full textISSN:2623-334
Reduced order modeling for the dynamic analysis of structures with nonlinear interfaces
No full textIn the present paper, linear substructures with nonlinearities localized at their interfaces, such as the joints in a beam structure, are studied. By subdivision of the total structure into substructures, reduced subsystems are obtained by component mode synthesis. Nonlinear elements are introduced at supports or between substructures. A numerical example is presented where a beam subjected to blast loading is studied. The influence of the nonlinear behavior as well as the number of retained fixed-interface normal modes in the reduced subsystems are evaluated. The response is also compared to the response of equivalent single-degree-of-freedom systems, which are frequently employed in blast load design calculations. For the load cases studied, the displacement computed from an equivalent single-degree-of-freedom system correspond fairly well to the displacement given by a refined two-dimensional beam model, reduced by substructuring. In contrast, the shear force differs significantly due to that higher order modes are neglected in the single-degree-of-freedom system
A nonlinear material model of corroded rebars for seismic response of bridges
No full textA generalized cyclic steel model characterized by isotropic and kinematic hardening, inelastic buckling in compression and corrosion for the rebar in reinforced concrete (RC) structures is presented. This model has been implemented in in-house fiber program CY.R.U.S.-M developed in MATLAB, to perform the seismic analysis of RC sections. The model is especially accurate, with respect to experimental cyclic behavior of rebars with buckling in compression, in case the strain in compression does not exceed 1.2 - 1.5 %. Four RC sections were selected as the case studies for a single concrete geometry and different steel configurations assumed representative of RC bridge piers (in a suitable scale) and subjected to a cyclic curvature history representative of a severe seismic load, not far from collapse. Different rebar characteristics (yielding stress, maximum stress, hardening ratio), axial loads, corrosion percentages have been selected to perform some cyclic parametric analyses. The numerical results have shown that the maximum strain of the rebar in compression is always smaller than 1.2 - 1.5 % and therefore the simple model for the steel is a valid tool for the structural assessment. Finally, corrosion of the rebars reduces the section capacity in term of strength and energy dissipation.</p
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