Fully coupled multi-physics nonlinear analysis of structural space frames subjected to fire using the direct stiffness method
TL;DR: In this paper, a fully coupled hydro-thermo-mechanical formulation based on the direct stiffness method for analysis of steel and reinforced concrete structural space frames was developed for space frames.
Abstract: This article develops a fully coupled hydro-thermo-mechanical formulation based on the direct stiffness method for analysis of steel and reinforced concrete structural space frames. The superiority...
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TL;DR: In this article, an approach using corotational layered beam is proposed to mitigate fire risk in reinforced concrete (RC) structures and appropriate structural resistance against it has to be ensured.
Abstract: Fire is a critical risk in reinforced concrete (RC) structures and appropriate structural resistance against it has to be ensured. In this contribution, an approach using corotational layered beam ...
6 citations
Cites background or methods from "Fully coupled multi-physics nonline..."
...Noteworthy recent developments incorporate a two-way thermo-mechanical coupling in 2D (Prakash and Srivastava, 2018b) and 3D (Prakash and Srivastava, 2018a) based on a direct stiffness method....
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...…the generalized strains and is supposed to be the same for both concrete and steel materials, based on a perfect bonding assumption between the steel reinforcements and concrete, as in Balaji et al. (2016), Bamonte and Lo Monte (2015), Kodur and Dwaikat (2008), and Prakash and Srivastava (2018b)....
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...Using the Bernouilli beam theory that neglects shear strains is recognized to be a good approximation for beams with a length/height aspect ratio of roughly over 10 and was shown to yield good results in Kodur and Dwaikat (2008) and Prakash and Srivastava (2018a, 2018b)....
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TL;DR: In this paper , the sensitivity of reinforced concrete structures under fire loading was investigated using a relatively low cost 2D corotational layered beam finite element in a reduced latin hypercube sampling framework.
Abstract: The sensitivity of the structural response to variations of material and cross sectional geometrical parameters is investigated for reinforced concrete structures under fire loading. A relatively low cost 2D corotational layered beam finite element is employed in a reduced latin hypercube sampling framework for this purpose. The structural response is assessed in terms of vertical deflection versus time, failure time and cross sectional stress/strain distribution using standard fire curves. The numerical models represent experimentally tested cases in the literature and operate with experimentally derived parameter sets, when possible. A minimum set of three RVs, the bottom concrete cover thickness, steel and concrete yield stregths, out of the initial full set of 12 are identified that drastically reduces the number of RVs and thus the stochastic computation’s cost, while keeping a reasonable envelop for the results. The relationship between structural behavior, material degradation and data extracted from the cross sectional behavior is also successfully established and used to explain why the random set can be reduced to three parameters.
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TL;DR: In this paper, the authors present a review of the literature on modeling infill-frames under fire exposure, highlighting the major challenges in developing generic numerical models for analyzing thermo-mechanical behavior of infillframes and critically reviewing the available approaches for modelling infillframe subjected to fire.
Abstract: Purpose
Reinforced concrete structural frames with masonry infills (infill-frames) are commonly used for construction worldwide. While the behavior of such frames has been studied extensively in the context of earthquake loading, studies related to their fire performance are limited. Therefore, this study aims to characterize the behavior of infill-frames under fire exposure by presenting a state-of-the-art literature review of the same.
Design/methodology/approach
Both experimental and computational studies have been included with a special emphasis on numerical modeling (simplified as well as advanced). The cold behavior of the infill-frame and its design requirements in case of fire exposure are first reviewed to set the context. Subsequently, the applicability of numerical modeling strategies developed for modeling cold infill-frames to simulate their behavior under fire is critically examined.
Findings
The major hurdles in developing generic numerical models for analyzing thermo-mechanical behavior of infill-frames are identified as: lack of temperature-dependent material properties, scarcity of experimental studies for validation and idealizations in coupling between thermal and structural analysis.
Originality value
This study presents one of the most popular research problems connected with practical and reliable utilization of numerical models, as a good alternative to expensive traditional furnace testing, in assessing fire resistance of infill-frames. It highlights major challenges in thermo-mechanical modeling of infill-frames and critically reviews the available approaches for modeling infill-frames subjected to fire.
13 citations
TL;DR: In this article, a framework based on the direct stiffness method for nonlinear thermo-mechanical analysis of reinforced concrete plane frames subjected to fire is presented, which accounts for geometric nonlinearity.
Abstract: This article presents a framework based on the direct stiffness method for nonlinear thermo-mechanical analysis of reinforced concrete plane frames subjected to fire. It accounts for geometric nonl...
12 citations
TL;DR: In this article, a finite element formulation based on positions to deal with steel structures under high temperatures is presented, where the thermal analysis consists in achieving, along time, the temperature profile at frame elements cross sections that affects the constitutive relations and, consequently, residual stresses at the structural mechanical equilibrium.
10 citations
TL;DR: In this article, a coupled framework for analysis of reinforced concrete (RC) and steel planar frames subjected to fire is developed with three-way coupling between heat transfer, mechanical deformations and pore pressure build-up.
9 citations
TL;DR: In this article, a beam-column approach is proposed for large displacement and stability analysis of elastic plane frames subjected to temperature changes, taking into account the effect of curvature due to temperature gradient across the element cross section.
Abstract: Procedure for large displacement and stability analysis of elastic plane frames subjected to temperature changes is presented. The method of analysis is based on an Eulerian (corotational) formulation, which was developed initially for static loads, and is extended herein to include thermal effects. Local element force-deformation relationships are derived using the beam-column theory taking into consideration the effect of curvature due to temperature gradient across the element cross section. The changes in element chord lengths due to thermal axial strain, and bowing due to temperature gradient, are taken into account. This "beam-column" approach, using stability and bowing functions, requires significantly fewer elements per member (i.e., a beam or a column) for the analysis of a framed structure than the "finite-element" approach. A computational technique, using Newton-Raphson iteration, is developed to determine the nonlinear responses of structures. Numerical solutions are presented for a number of benchmark structures to demonstrate the feasibility of the proposed method of analysis.
9 citations