Studies on the behavior of Reinforced Concrete Short Column subjected to fire

Balaji, Aneesha; K, Muhamed Luquman; Nagarajan, Praveen; Pillai, T. M. Madhavan

doi:10.1016/j.aej.2015.12.022

Cited by 25 publications

(6 citation statements)

References 14 publications

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“…According to the National Building Code of Canada (NBCC) (2015), fire-resistance rating is the duration of time during which the material can adequately withstand the passage of flame and transmission of heat under standard fire exposure. Some of the factors that affect the fire resistance of a reinforced concrete element include concrete cover thickness, moisture content, configuration of confining reinforcement, duration and type of fire, load intensity and grade of concrete (Kodur et al, 2017;Balaji et al, 2016). Building fires are different and their development, spread and severity are usually unpredictable.…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of the residual compressive strength of concrete columns subjected to different fire durations and load ratios

Nair

Salem

2020

JSFE

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Purpose At elevated temperatures, concrete undergoes changes in its mechanical and thermal properties, which mainly cause degradation of strength and eventually may lead to the failure of the structure. Retrofitting is a desirable option to rehabilitate fire damaged concrete structures. However, to ensure safe reuse of fire-exposed buildings and to adopt proper retrofitting methods, it is essential to evaluate the residual load-bearing capacity of such fire-damaged reinforced concrete structures. The focus of the experimental study presented in this paper aims to investigate the fire performance of concrete columns exposed to a standard fire, and then evaluate its residual compressive strengths after fire exposure of different durations. Design/methodology/approach To effectively study the fire performance of such columns, eight identical 200 × 200 × 1,500-mm high reinforced concrete columns test specimens were subjected to two different fire exposure (1- and 2-h) while being loaded with two different load ratios (20% and 40% of the column ultimate design axial compressive load). In a subsequent stage and after complete cooling down, residual compressive strength capacity tests were performed on each fire exposed column. Findings Experimental results revealed that the columns never regain its original capacity after being subjected to a standard fire and that the residual compressive strength capacity dropped to almost 50% and 30% of its ambient temperature capacity for the columns exposed to 1- and 2-h fire durations, respectively. It was also noticed that, for the tested columns, the applied load ratio has much less effect on the column’s residual compressive strength compared to that of the fire duration. Originality/value According to the unique outcomes of this experimental study and, as the fire-damaged concrete columns possessed considerable residual compressive strength, in particular those exposed to shorter fire duration, it is anticipated that with proper retrofitting techniques such as fiber-reinforced polymers (FRP) wrapping, the fire-damaged columns can be rehabilitated to regain at least portion of its lost load-bearing capacities. Accordingly, the residual compressive resistance data obtained from this study can be effectively used but not directly to adopt optimal retrofitting strategies for such fire-damaged concrete columns, as well as to be used in validating numerical models that can be usefully used to account for the thermally-induced degradation of the mechanical properties of concrete material and ultimately predict the residual compressive strengths and deformations of concrete columns subjected to different load intensity ratios for various fire durations.

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Section: Introductionmentioning

confidence: 99%

Experimental determination of the residual compressive strength of concrete columns subjected to different fire durations and load ratios

Nair

Salem

2020

JSFE

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“…where y i is the average vertical coordinate of layer i, computed from the sectional center of gravity (Figure 2). A perfect bonding between the steel reinforcements and concrete is supposed, as in Balaji et al (2016), Bamonte and Lo Monte (2015), Kodur and Dwaikat (2008), Prakash and Srivastava (2018b). For the layers containing the steel reinforcements the stresses in concrete and steel are computed separately, using 1D constitutive laws fitted to experimental data from the literature.…”

Section: Multilayered Beam Formulationmentioning

confidence: 99%

Probabilistic investigation of reinforced concrete structures under fire loading accounting for material and geometric uncertainties

Sosso

Berke

2023

Advances in Structural Engineering

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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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“…x,tot is computed from 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). Stresses in concrete and steel are computed separately from the layer strain using 1D constitutive laws that can be easily fitted to experimental data from the literature.…”

Section: Computational Formulationmentioning

confidence: 99%

“…The vast majority of the recent numerical efforts use commercial software (Jiang et al, 2017;Nguyen et al, 2018), specific in-house developed codes (Wu et al, 2018), or open sources packages (Jiang et al, 2014) with sometimes a limited set of constitutive models by default. The numerical approaches can be classified into two main types, namely: the detailed models (full 3D meshing using solid FE) (Ba et al, 2016;Balaji et al, 2016;Gao et al, 2013;Raouffard and Nishiyama, 2018;Sanad et al, 2000) and reduced approaches using fiber/layer cross-section discretization in 2D/3D (Cai et al, 2003;Franssen, 2005;Kodur and Dwaikat, 2008).…”

mentioning

confidence: 99%

Computational analysis of reinforced concrete structures subjected to fire using a multilayered finite element formulation

Sosso

Gutierrez

Berke

2021

Advances in Structural Engineering

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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 finite elements is employed in which the cross-section temperature is derived from a low-cost closed form model, as opposed to the more commonly used fully computational thermal analysis. The effect of geometrical and material nonlinearities (constitutive behavior fitted to experimental data for concrete and steel), material degradation as a function of temperature rise, and the contributions of thermal, transient, and creep strains are incorporated in the structural analysis. The computational results are favorably compared to experimental data from the literature for an RC beam and for a larger RC frame. Taking benefit of the layered beam formulation offering local insight into the cross-sectional and material behavior, the relationship between the structural degradation and data extracted from the cross-sectional behavior is successfully established. Noteworthy originalities of the contribution are the use of ultimate strain and its evolution as a function of temperature for both materials and the explanation of the observed structural response in fire conditions from cross-sectional data.

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Studies on the behavior of Reinforced Concrete Short Column subjected to fire

Cited by 25 publications

References 14 publications

Experimental determination of the residual compressive strength of concrete columns subjected to different fire durations and load ratios

Experimental determination of the residual compressive strength of concrete columns subjected to different fire durations and load ratios

Probabilistic investigation of reinforced concrete structures under fire loading accounting for material and geometric uncertainties

Computational analysis of reinforced concrete structures subjected to fire using a multilayered finite element formulation

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