Microsoft Word - ETASR_V12_N5_pp9113-9119 Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9113 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads Mohamed Baghdadi LGC-ROI, Department of Civil Engineering Faculty of Technology University of Batna 2 Batna, Algeria m.baghdadi@univ-batna2.dz Mohamed S. Dimia LGC-ROI, Department of Civil Engineering Faculty of Technology University of Batna 2 Batna, Algeria ms.dimia@univ-batna2.dz Djassem Baghdadi Laboratory of Research in Civil Engineering University of Mohamed Khider Biskra, Algeria djassem.baghdadi@univ-biskra.dz Received: 2 July 2022 | Revised: 17 July 2022 | Accepted: 21 July 2022 Abstract-Columns are the structural members of buildings that ensure structural stability. A fire can severely affect the columns' structural performance by degrading the properties of their constituent materials, thereby reducing the strength capacity, stiffness, and stability. In seismic zones, the knowledge of the post-fire behavior of these elements is a fundamental requirement for a realistic seismic performance assessment. This study utilized numerical analysis using the parametric fire model of Eurocode-1 to estimate the post-fire axial and lateral performance of reinforced concrete columns. In the first step, the axial load- bearing capacity was evaluated from a parametric study for cantilever columns. In the second step, the lateral load capacity, force-displacement behavior, stiffness, ductility, energy dissipation capacity, and residual displacements were estimated to determine the impact of fire damage on the behavior of columns under lateral loads. The results showed that both the lateral load capacity and the ductility of the reinforced concrete columns decreased significantly due to fire exposure. This also indicated that fire damage decreases the vertical load-bearing capacity, and the reduction in lateral capacity was attributed to the loss of concrete's compressive strength. The column characteristics that significantly influence the residual response behavior were identified as section size, column height, axial load ratio, and concrete's compressive strength. Keywords-natural fire; columns; post-fire behavior; fire damage; residual strength; lateral load capacity I. INTRODUCTION Fires and earthquakes are among the most severe conditions buildings may face. In the case of fire, the structural and nonstructural elements may undergo different changes depending on the intensity and exposure duration. The fire safety of Reinforced Concrete (RC) structures highly depends on their fire resistance, which relies on the thermal conductivity and the resistance of load-bearing elements such as walls, columns, and beams. Fire damage leads to a decrease in the strength and deformation properties of structures. A Post-Fire Earthquake (PFE) is an eventual disaster, but its damage to RC members is complicated and usually affected by uncertain factors. The reinforced concrete structure can remain standing after a fire, or after an earthquake. The full or partial collapse of concrete buildings during a fire is rare, however, earthquakes following a fire can cause significant damage depending on the residual properties of the structural elements. In post-fire performance assessment, it should be decided whether to repair and strengthen or demolish and rebuild the entire structure, taking into account the earthquake loads during its remaining service life. The behavior of a structure after a fire is related to its residual bearing capacity, so it is necessary to determine, quantify, and compare it with the safety levels. The study of the impact of earthquakes on structures damaged by real fires is a fundamental issue in assessing concrete's structural behavior in severe load combinations. Although the sequential application of these extreme loads may be too severe in most cases, this strategy may be appropriate for the design of important structures, where cost and technology are no barrier. However, current regulations do not consider fire and earthquake hazards [1]. Several studies investigated the influence of fire on the mechanical strength of RC members and structures [2-4]. Post- fire material tests showed that concrete's mechanical properties degrade after fire exposure and do not fully recover after cooling [5-7]. Different models were proposed in [8, 9] on the post-fire full stress-strain response of fire-damaged concrete and the residual stress-strain relationship after exposure to high Corresponding author: Mohamed Baghdadi Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9114 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads temperatures. Numerical investigations in [10, 11] evaluated the impact of fire duration and intensity on the residual load- bearing capacity and delayed failure of reinforced concrete columns. Experimental research and test results on the post-fire behavior of RC columns were presented in [12, 13]. A new modified finite element model was developed in [14] to predict the behavior and strength of concrete-filled steel tubular subjected to axial compression, considering the influence of some determinant parameters. A numerical study examined the fire behavior of thermally insulated strengthened RC beams subjected to fire exposure in [15]. The effect of fire on the flexural behavior of RC beams was studied in [16, 17]. An experimental study on the seismic behavior of high- performance concrete frames after a fire was presented in [18], showing that fire exposure can transform the failure mode of a frame subjected to reverse-cyclic loads from strong-column- weak-beam to strong-beam-weak-column with poor cyclic performance. Another study was conducted in [19] on the seismic performance of reinforced concrete beam-column joints after a fire and their practical strengthening. The performance of RC frame structures in post-earthquake fire loading and their failure times were analyzed in [20, 21]. In [22, 23], the seismic performance of RC short columns with light transverse reinforcement and RC beam-column joints under varying axial forces was investigated. Several studies on fire resistance and post-fire seismic behavior of concrete shear walls were carried out experimentally and numerically [24-27]. A limited number of studies attempted to estimate the post- fire lateral capacity performance of concrete columns. Although the behavior of reinforced concrete columns at elevated temperatures has been extensively investigated under service loads after cooling, studies on post-fire seismic behavior of RC structural elements are extremely rare. The results of [28, 29] evaluated the post-fire seismic performance of reinforced precast concrete columns damaged by fire to determine the impact of fire damage on force-displacement behavior, moment-curvature relationship, and residual displacements. An experimental study investigated the seismic performance of shear critical post-heated RC columns that had been repaired [30]. In [31], the results of a study on the seismic resistance of strengthened concrete members after fire exposure were presented. Furthermore, a numerical investigation of the response simulation of RC columns under lateral loads was conducted in [32]. In [33], the residual strength and lateral/seismic load capacity of RC columns after fire exposure were evaluated using numerical analysis. This paper presents a numerical analysis that investigates the behavior of RC columns damaged by fire under vertical load and evaluate the lateral bearing capacity under horizontal loads, including a parametric study to identify the influential column characteristics. This study employed the structural analysis software SAFIR [34], which is capable of 3D simulation of building structures in fire. The parametric natural fire curves of Eurocode-1 were selected to perform the simulations. II. EVALUATION OF VERTICAL RESIDUAL LOAD-BEARING CAPACITY OF COLUMNS Each column was first subjected to constant loading, and then a section of the column was exposed to natural fire to assess its residual characteristics. Loading was applied in successive simulations in a decreasing and monotonous manner, and the time of the collapse was calculated for each loading level. The corresponding loading level represents the load-bearing capacity of the column to resist natural fire, including the heating and cooling phases. A. Time-Temperature Curves Used The fire curves were taken from the parametric fire model of Annex (A) of EN 1991-1-2(2002) [35] that represents the action of a natural fire, including the cooling phase. Figure 1 shows the various used fire curves, differing by the duration of the heating phase of 15, 30, 60, 90, and 120 minutes. Fig. 1. Time-temperature curves. B. Parametric Studies The following parameters were considered to evaluate the total residual capacity: • The section size of the column: 20×20cm, 30cm×30cm, 40×40cm, 60×60cm, and 80×80cm. • The duration of the heating phase of the fire (tpeak): 15, 30, 60, 90, and 120 minutes to assess the influence of the maximum temperature on the residual characteristics. • The height of the column: 3, 4, and 5m. • The columns were cantilever, fixed in rotation at the bottom and free at the top. C. Results and Discussions 1) Influence of the Effective Height of the Column Table I shows the results for columns, considering their height, before and after fire exposure. A 30×30cm section was chosen to perform the simulations. For the same height, the influence of the maximum temperature during fire was considerable: a loss of 70% of vertical capacity (Nr) was found for the fire of tpeak=60min for 3m columns. Considering the variation in column height for the same fire, the residual vertical capacity (Nr) of the 3m column was found to be greater than the 5m column's (about 90%). Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9115 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads TABLE I. VERTICAL LOAD BEARING CAPACITY BEFORE (N20°C) AND AFTER FIRE EXPOSURE (NR) FOR COLUMNS Height (m) Before fire N20°C(kN) Nr (kN) after exposure Fire of tpeak=15min Fire of tpeak=30min Fire of tpeak=60min Fire of tpeak=90min Fire of tpeak=120min 3 1978 798 669 589.5 559.5 540 4 1446 589.5 498 441 420 406.5 5 972 396 339 304.5 292.5 283.5 2) Influence of Section Size Table II presents the results of different-sized sections having the same height (4m). For the 40×40cm section, a loss of 75% was found for a 60min fire and a loss of 85% was found for the section of 80×80cm. The maximum temperature during fire exposure and cooling time was among the most important parameters responsible for the degree of concrete damage. The greater the section size, the higher the temperature gradient during the cooling phase and therefore, the higher damage induced in the concrete. With natural cooling, the interior temperature gradient within the concrete can be higher than during the heating phase. TABLE II. VERTICAL LOAD BEARING CAPACITY BEFORE (N20°C) AND AFTER FIRE EXPOSURE (Nr) OF SECTIONS Section Before fire N20°C (kN) Nr (kN) after exposure Fire of tpeak=15min Fire of tpeak=30min Fire of tpeak=60min Fire of tpeak=90min Fire of tpeak=120min sec20×20cm 295.5 123 108 99 96 93 sec30×30cm 1446 589.5 498 441 420 406.5 sec40×40cm 1725 652.5 537 466.5 439.5 421.5 sec60×60cm 8988 2847 2185.5 1776 1621.5 1521 sec80×80cm 16410 4689 3433.50 2658 2365.50 2175 III. LATERAL LOAD CAPACITY EVALUATION OF FIRE- DAMAGED RC COLUMNS The horizontal load capacity was also evaluated to examine the column's behavior under combined vertical and horizontal loads, which is a real situation that a column must survive in frame structures. The lateral load was assumed to be a seismic load. This process utilized a numerical SAFIR model in a cold situation to investigate the lateral load response of the columns. The axial load was 25% and 50% of the residual vertical capacity Nr and was held constant throughout the analysis. The lateral load was applied horizontally at the top of the columns in displacement-controlled mode and incremented from zero up to the column failure, as shown in Figure 2. It was possible to estimate the maximum horizontal load Hu that the column can support. The horizontal load Hu represents the shear force that an earthquake can induce in a column. Fig. 2. Evolution of Hu and Nr. A. Horizontal Load-Bearing Capacity (Hu) with Vertical Load The column was subjected to both axial load and lateral deformation. The axial load used was the vertical load capacity of the column after fire exposure. Two loading rates were used: 25 and 50% of the residual bearing capacity. 1) Effect of Effective Height For each fire and different heights, 44% and 42% loss of lateral capacity were found when applying 25% and 50% axial load of Nr respectively, as shown in Figure 3. (a) (b) Fig. 3. Hu as a function of various heights for (a) 0.25 of Nr, (b) 0.5 of Nr. Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9116 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads However, as can be observed in Figure 3, the reductions in the lateral load capacities for the same height were less than the reductions in the compressive strength, which minimized the impact of the compressive strength on the column behavior. 2) Influence of the Size of the Sections Figure 4 shows the evolution of Hu considering the effect of the section and the properties of the residual material after fire exposure. As the duration of fire increases, the residual properties of the material decrease, and a loss of 10% to 35% was evaluated for all columns considering the same height (4m). This degradation was due to the additional loss of the concrete’s compressive resistance caused by the continuity of the evolution of temperatures in the massive sections. For the same fire, the horizontal load-bearing capacity of the column can increase by 97% depending on the section's dimensions. (a) (b) Fig. 4. Hu as a function of section size: (a) 0.25 of Nr (b) 0.5 of Nr. B. Evolution of the Maximum Lateral Displacement 1) Influence of the Height of the Column Figure 5 shows the maximum lateral displacements at the top of the column for heights of 3, 4, and 5m using the same section of 30×30cm. Considering the residual resistance of the materials after the fire, the maximum lateral displacement was calculated for each fire. The results showed that the displacement value increased about 36% at the top of the 5m column compared to the reference column of 3m. The largest lateral displacement was 16cm for the 5m column exposed to fire with a heating phase (tpeak) of 15 minutes. Fire exposure has a greater effect on the residual compressive strength of concrete, and the structural response is governed by the geometrical properties of the column, such as inertia and height. Fig. 5. Evolution of maximal lateral displacement. 2) Influence of the Sections of Columns Figure 6 shows the influence of the section’s size on the maximum lateral displacement. For the 20×20cm sections, the displacement increased gradually and its maximum was about 13cm. This growth was due to fire damage to the mechanical residual property of the materials, and the strength of the columns decreased following the degradation of the strength. For the 80×80cm sections, the displacement of 5cm has a small variation, showing that a column's behavior depends on its geometrical properties. Fig. 6. Influence of section size on the maximum lateral displacement of a 4m column height. C. Lateral Loads and Displacement Response Analysis Horizontal displacements were calculated using the incremental method, evaluating the displacement for each time step. Figure 7 shows the load-lateral displacement which traces the development of lateral displacement on the top of columns under the incremental loading. 1) Energy Dissipation The area enclosed by the curve and the horizontal axis in Figure 8 is defined as the energy dissipated by the columns, representing the ability to consume seismic energy through plastic deformations. Figure 7 shows that these curves are approximately straight lines before cracking. Within each curve, the decrease in secant stiffness caused by fire loading is somewhat insignificant, leading to small energy dissipation. However, they bend towards the displacement axis towards the end of loading. In other words, the top lateral displacements develop at accelerating rates before the failure of the column. Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9117 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads The curves indicate that the stiffness of an unheated column is higher than that of a heated one. This is because elevated temperatures cause more damage to the stiffness of the column subjected to greater temperature exposure (120min fire). Figure 8 also shows that the stiffness of the column exposed fires of 60, 90, and 120 minutes is very similar. This can be attributed to the damage caused by the high-temperature effect on the residual resistance of concrete. Among the curves presented, the stiffness of the column that has not been exposed to elevated temperature is the highest. The loading curves indicate that an elevated temperature has a significant effect under these conditions. Energy dissipation can be divided into two phases: pre-cracking and post-cracking. The energy dissipation capacity in the pre-cracking phase is very small. Fig. 7. Load-displacement curves of 3m columns. Fig. 8. Energy dissipated by the column. 2) Ductility Degradation The displacement ductility factor μΔ, which is the ratio of the ultimate displacement Δu to the yield displacement Δy, was calculated for each column to compare the performance in terms of sustained ductility. Under a particular drift level, Table III shows that the ductility of the unheated column is about 60% of the fire-damaged column. The differences in ductility mainly reflect the effect of fire on mechanical properties. Furthermore, the differences in ductility mainly reflect that elevated temperature exposure reduces the capacity of the column. It can be concluded that the exposing temperature has a remarkable effect on the load-bearing capacity of the columns. The ductility of the columns was not found to be affected by fire exposure up to 30min. TABLE III. DUCTILITY PARAMETERS OF THE COLUMNS Before fire (at 20°C) After fire of tpeak=15min After fire of tpeak=30min After fire of tpeak=60min After fire of tpeak=90min After fire of tpeak=120min Lateral yield displacement Δy(cm) 3.387 4.544 5.506 5.36 5.01 5.1 Lateral ultimate displacement Δu(cm) 5.405 6.368 5.506 5.36 5.01 5.1 Ductility factor: μΔ=Δu/Δy 1.6 1.40 1 1 1 1 IV. CONCLUSIONS The following remarks can be extracted from this study: • The results showed that the lateral load capacity and ductility decreased substantially as a result of fire exposure. • Post-fire lateral load capacities were not considerably affected by the increase in fire duration up to 60min. After 60min of fire exposure, a little reduction in the lateral load capacity of the column was observed, which minimized the impact of the concrete compressive strength loss on the post-fire lateral capacity of the columns. • The reduction in lateral load capacity appeared to be caused by the residual properties of the concrete after fire exposure. For low axial loads (25% of Nr), the effects of vertical compressive load on the behavior of the columns were considerable. • The energy dissipation of the columns was not significantly affected by fires with duration up to 30min. For a column subjected to a 90min fire, the reduction was about 25% compared to an unheated one, which was attributed to the loss of compressive strength. The stiffness of the column after a 30min fire was not affected. The slope of energy dissipation curves was confusing after a 30min fire. • Ductility reduction was significantly affected compared to an unheated column after a 15min fire. This reduction was attributed to the post-fire loss in the mechanical properties of concrete. This can be explained by the greater loss in concrete’s compressive strength and thereby the lower lateral load-bearing capacity of the columns. • The application of the available Eurocode model for concrete after fire exposure resulted in a good estimation of the residual capacity of fire-damaged columns compared to the available existing results. NOMENCLATURE Nr = Vertical load-bearing capacity of a column. Hu = Horizontal load-bearing capacity of a column. Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9118 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads tpeak = Time corresponding to the end of the heating phase - duration of the heating phase of the fire. Δy = Lateral yield displacement. Δu = Lateral ultimate displacement. μΔ = Ductility factor. REFERENCES [1] A. S. Usmani, "Research Priorities for Maintaining Structrural Fire Resistance after Seismic Damage," presented at the 14th World Conference on Earthquake Engineering, Beijing, China, Oct. 2008. [2] D. Qin, P. Gao, F. Aslam, M. Sufian, and H. Alabduljabbar, "A comprehensive review on fire damage assessment of reinforced concrete structures," Case Studies in Construction Materials, vol. 16, Jun. 2022, Art. no. e00843, https://doi.org/10.1016/j.cscm.2021. e00843. [3] A. Agrawal and V. K. R. Kodur, "A Novel Experimental Approach for Evaluating Residual Capacity of Fire Damaged Concrete Members," Fire Technology, vol. 56, no. 2, pp. 715–735, Mar. 2020, https://doi.org/10.1007/s10694-019-00900-1. [4] J. Wróblewska and R. Kowalski, "Assessing concrete strength in fire- damaged structures," Construction and Building Materials, vol. 254, Sep. 2020, Art. no. 119122, https://doi.org/10.1016/j.conbuildmat. 2020.119122. [5] R. Felicetti and P. G. Gambarova, "The Effects of High Temperature on the Residual Compressive Strength of High-Strength Siliceous Concretes," Materials Journal, vol. 95, no. 4, pp. 395–406, Jul. 1998, https://doi.org/10.14359/382. [6] J. Lee, Y. Xi, and K. Willam, "Properties of Concrete after High- Temperature Heating and Cooling," Materials Journal, vol. 105, no. 4, pp. 334–341, Jul. 2008, https://doi.org/10.14359/19894. [7] Y. N. Chan, G. F. Peng, and M. Anson, "Residual strength and pore structure of high-strength concrete and normal strength concrete after exposure to high temperatures," Cement and Concrete Composites, vol. 21, no. 1, pp. 23–27, Jan. 1999, https://doi.org/10.1016/S0958- 9465(98)00034-1. [8] A. Nassif, "Postfire full stress–strain response of fire-damaged concrete," Fire and Materials, vol. 30, no. 5, pp. 323–332, 2006, https://doi.org/10.1002/fam.911. [9] Y. F. Chang, Y. H. Chen, M. S. Sheu, and G. C. Yao, "Residual stress– strain relationship for concrete after exposure to high temperatures," Cement and Concrete Research, vol. 36, no. 10, pp. 1999–2005, Oct. 2006, https://doi.org/10.1016/j.cemconres.2006.05.029. [10] M. Salah Dimia, M. Guenfoud, T. Gernay, and J.-M. Franssen, "Collapse of concrete columns during and after the cooling phase of a fire," Journal of Fire Protection Engineering, vol. 21, no. 4, pp. 245– 263, Nov. 2011, https://doi.org/10.1177/1042391511423451. [11] T. Gernay and M. Salah Dimia, "Structural behaviour of concrete columns under natural fires," Engineering Computations, vol. 30, no. 6, pp. 854–872, Jan. 2013, https://doi.org/10.1108/EC-05-2012-0103. [12] T. T. Lie, J. L. Woollerton, and Institut de recherche en construction (Canada), Fire resistance of reinforced concrete columns, test results. Ottawa, Canada: National Research Council of Canada, Institute for Research in Construction, 1988. [13] Y.-H. Chen, Y. F. Chang, G. C. Yao, and M.-S. Sheu, "Experimental research on post-fire behaviour of reinforced concrete columns," Fire Safety Journal, vol. 44, no. 5, pp. 741–748, Jul. 2009, https://doi.org/ 10.1016/j.firesaf.2009.02.004. [14] P. C. Nguyen, D. D. Pham, T. T. Tran, and T. Nghia-Nguyen, "Modified Numerical Modeling of Axially Loaded Concrete-Filled Steel Circular-Tube Columns," Engineering, Technology & Applied Science Research, vol. 11, no. 3, pp. 7094–7099, Jun. 2021, https://doi.org/10.48084/etasr.4157. [15] A. S. Ali and H. A. Al-Baghdadi, "Behavior of RC Beams Strengthened with NSM-CFRP Strips Exposure to Fire," IOP Conference Series: Earth and Environmental Science, vol. 856, no. 1, Jun. 2021, Art. no. 012035, https://doi.org/10.1088/1755-1315/856/1/ 012035. [16] H. M. Hekmet and A. F. Izzet, "Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature," Engineering, Technology & Applied Science Research, vol. 9, no. 5, pp. 4759–4768, Oct. 2019, https://doi.org/10.48084/etasr.3059. [17] L. Ping, X. Jing, B. Othman, F. Yuefei, Z. B. A. Kadir, and X. Ping, "An Intercultural Management Perspective of Foreign Student’s Adaptation in Chinese Universities: A Case Study of China Three Gorges University," Engineering, Technology & Applied Science Research, vol. 9, no. 2, pp. 3971–3977, Apr. 2019, https://doi.org/ 10.48084/etasr.2589. [18] X. Jianzhuang and X. Meng, "An experimental study on the seismic behavior of HPC frames after fire," China Civil Engineering, vol. 38, no. 8, pp. 36–42, 2005. [19] X. Liu, T. Gernay, L. Li, and Z. Lu, "Seismic performance of post-fire reinforced concrete beam-column joints strengthened with steel haunch system," Engineering Structures, vol. 234, May 2021, Art. no. 111978, https://doi.org/10.1016/j.engstruct.2021.111978. [20] M. Moradi, H. Tavakoli, and G. AbdollahZade, "Sensitivity analysis of the failure time of reinforcement concrete frame under postearthquake fire loading," Structural Concrete, vol. 21, no. 2, pp. 625–641, 2020, https://doi.org/10.1002/suco.201900165. [21] H. Mostafaei and T. Kabeyasawa, "Performance of a six-story Reinforced Concrete Structures in Post-Earthquake Fire," in Proceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering, Toronto, Canada, Jul. 2010, Art. No. 659. [22] C. T. N. Tran and B. Li, "Seismic performance of RC short columns with light transverse reinforcement," Structural Engineering and Mechanics, vol. 67, no. 1, pp. 93–104, 2018, https://doi.org/10.12989/ sem.2018.67.1.093. [23] Y. Hu, M. Maeda, Y. Suzuki, and K. Jin, "Seismic performance of exterior R/C beam-column joint under varying axial force," Structural Engineering and Mechanics, vol. 78, no. 5, pp. 623–635, 2021, https://doi.org/10.12989/sem.2021.78.5.623. [24] J. Zh. Xiao, J. Li, and F. Jiang, "Research on the seismic behavior of HPC shear walls after fire," Materials and Structures, vol. 37, no. 8, pp. 506–512, Oct. 2004, https://doi.org/10.1007/BF02481574. [25] G. R. Liu, "Experimental study on fire resistance and post-fire seismic behavior of concrete shear wall," Ph.D. dissertation, Dalian University of Technology, 2010. [26] S. Ni and A. C. Birely, "Post-fire seismic behavior of reinforced concrete structural walls," Engineering Structures, vol. 168, pp. 163– 178, Aug. 2018, https://doi.org/10.1016/j.engstruct.2018.04.018. [27] M. Baghdadi, M. S. Dimia, M. Guenfoud, and A. Bouchair, "An experimental and numerical analysis of concrete walls exposed to fire," Structural Engineering and Mechanics, vol. 77, no. 6, pp. 819–830, Jan. 2021, https://doi.org/10.12989/sem.2021.77.6.819. [28] A. Ilki and U. Demir, "Factors Affecting the Seismic Behavior of Reinforced Concrete," NED University Journal of Research - Special Issue on First South Asia Conference on Earthquake Engineering, Feb. 2019. [29] U. Demir, M. F. Green, and A. Ilki, "Postfire seismic performance of reinforced precast concrete columns," PCI Journal, pp. 62–80, Nov. 2020. [30] C. G. Bailey and M. Yaqub, "Seismic strengthening of shear critical post-heated circular concrete columns wrapped with FRP composite jackets," Composite Structures, vol. 94, no. 3, pp. 851–864, Feb. 2012, https://doi.org/10.1016/j.compstruct.2011.09.004. [31] N. Benichou, H. Mostafaei, M. F. Green, and K. Hollingshead, "The impact of fire on seismic resistance of fibre reinforced polymer strengthened concrete structural systems," Canadian Journal of Civil Engineering, vol. 40, no. 11, pp. 1044–1050, Nov. 2013. [32] H. Mostafaei and J. K. Hum, "Response Simulation of Reinforced Concrete Columns Under Lateral Loads," National Research Council of Canada, Feb. 2010. https://doi.org/10.4224/20375047. [33] H. Mostafaei, F. J. Vecchio, and N. Bénichou, "Seismic Resistance of Fire-Damaged Reinforced Concrete Columns," in Improving the Seismic Performance of Existing Buildings and Other Structures, San Engineering, Technology & Applied Science Research Vol. 12, No. 5, 2022, 9113-9119 9119 www.etasr.com Baghdadi et al.: A Parametric Study of Fire-Damaged Reinforced Concrete Columns under Lateral Loads Francisco, California, United States, Dec. 2009, pp. 1396–1407, https://doi.org/10.1061/41084(364)128. [34] J.-M. Franssen and T. Gernay, "Modeling structures in fire with SAFIR®: theoretical background and capabilities," Journal of Structural Fire Engineering, vol. 8, no. 3, pp. 300–323, Jan. 2017, https://doi.org/10.1108/JSFE-07-2016-0010. [35] Eurocode 1: Actions on Structures: Part 1.2 General Actions : Actions on Structures Exposed to Fire. London, UK: BSI, 2002.