Fire Exposure Duration Research Articles

Strengthening Fire-Damaged Lightweight Concrete T-Beams Using Engineered Cementitious Composite with Basalt Fiber-Reinforced Polymer Grid

Lightweight concrete (LWC) is a long-standing development in the area of construction materials. LWC has become increasingly important for sustainable construction due to its reduced susceptibility to cracking. However, when exposed to extreme temperatures during fires, LWC can lose its compressive strength and ductility. This study investigates the performance of lightweight expanded clay aggregate (LECA) concrete T-beams exposed to elevated temperatures. The research also focuses on the use of an engineered cementitious composite with a basalt fiber-reinforced polymer grid (ECCBFG) as a rehabilitation method for fire-damaged T-beams. Key variables considered include the concrete cover thickness (20 and 30 mm), fire exposure duration (30 and 60 min), and thickness of the ECCBFG layer. Thermocouples were installed at various points within the beams to monitor the heat gradient across the cross-section. Fourteen concrete beam specimens were tested, including control beams, fire-damaged beams, and beams strengthened with the ECCBFG layer. Key performance parameters, such as the energy absorption, cracking load, ductility index, maximum load capacity, and corresponding displacement, were analyzed. The experimental results showed that the strengthened beams outperformed the fire-damaged beams, closely matching the performance of undamaged reference beams in most aspects, except energy absorption. The findings suggest that further research is needed to optimize certain performance indicators and address challenges in strengthening fire-damaged beams.

BEHAVIOR OF CONCRETE UNDER FIRE EXPOSURE

Service structures could be built from different materials and concrete is commonly used in construction due to its beneficial mechanical properties, such as its superior compressive strength, long-lasting durability, and ability to resist fire. Structures are anticipated to withstand the various loads they encounter during their operational lifespan, which can typically be determined based on factors such as the type of service, geographical location, and dimensions. These loads can be accurately modeled using advanced software tools that are continuously evolving. However, fire incidents are difficult to predict, making it challenging to foresee their location, timing, and the extent of their impact on structures, resulting reductions in strength and unexpected stress. Therefore, in this study, to examine the performance of concrete of different strength grades and reinforced concrete (RC) beam specimens exposed to fire at different temperatures, an experimental investigation was carried out. During the test, the maximum duration of fire exposure taken is four hours and maximum concrete surface temperature considered is limited to 246°C. For the RC beams, test was conducted under one-point loading with different specimens of 25 mm and 35 mm concrete covers. The results showed that, the strength of RC beam after fire exposure reduces up to 18% and the compression strength of concrete at 246°C of fire exposure temperature with 25 MPa and 30 MPa were observed to drop by 32%, and 48%, respectively as compared to initial strength. Moreover, comparison of experimental results with numerical models were made. The results revealed that the predicted values of the residual compressive strength proposed by Hertz's model are in good agreement with the experimental values.

Post-fire seismic performance of precast concrete columns with grouted sleeve connections: An experimental study

This research explores the effects of fire on the seismic behavior of precast concrete columns with grouted sleeve connections. Five precast columns were subjected to fire for 0, 60, and 97 min, then tested under axial loads and horizontal cyclic loading at compression ratios of 0.1 and 0.3. A comparative analysis was performed against a cast-in-place column, identically treated. The study found that fire exposure alters failure modes: non-exposed columns failed flexural, while those exposed for 60 min showed either flexural shear or shear bond failures, varying with axial compression. After 97 min fire exposure, shear bond failure was predominant. Fire exposure duration was inversely proportional to load-bearing capacity, ductility, stiffness, and energy absorption. Conversely, higher axial compression ratios increased load capacity and stiffness but decreased ductility, without significantly affecting energy absorption post-fire. The study culminates in a refined calculation method for estimating post-fire load capacity, achieving accuracy within 5 % error.

Enhancing fire resistance of glulam columns with modified laminas via resin impregnation and compression

Wood's vulnerability to combustion compromises its structural integrity during fire incidents, primarily due to a decrease in effective cross-section area. This study investigates the efficacy of impregnation Chinese fir lumbers with a 30 % concentration of borate-containing phenol–formaldehyde resin, coupled with a 30 % compression treatment, employed as exposed side laminas for glulam columns. Full-scale glulam columns underwent one-sided fire exposure to assess the impact of the modified laminas. Results reveal a significant increase in column ignition time by 55–195 s, due to the combined treatment. The charring rate of columns containing a single modified lamina in the fire-side zone decreased from 0.733 to 0.552 mm/min after 60 min of fire exposure and further reduced from 0.503 to 0.351 mm/min after 120 min fire exposure for double modified laminas. Compared to the control, glulam columns containing a single modified lamina showcased a 31 % increase in residual bearing capacity at 60 min fire exposure duration and a 62.1 % increase at 120 min with double modified laminas. ABAQUS simulation results corroborated experimental findings, highlighting substantial enhancement in fire resistance achieved due to the modified laminas in the fire-side zone.

Post-fire bond behaviour of reinforcement in concrete considering different bonded lengths and position of rebars

RC structures can be subjected to accidental fire load during their service life, which can have a strong negative effect on the bond strength. A reliable assessment of the bond behaviour after a fire event is essential to judge whether the fire affected structure is safe for further usage or does it require retrofitting or replacement. Until now, rather limited research has been carried out to understand the post-fire bond behaviour of reinforcement in concrete. This work reports and discusses the results of an experimental study on the post-fire (residual) bond behaviour carried out using beam-end-specimens, which simulate the boundary conditions closer to reality compared to conventional pull-out-specimens. The standard fire scenario is employed to expose the rebar to fire from one-side and three-sides for simulating the boundary conditions of a slab and a beam respectively. The specimens are subjected to fire for the target fire exposure duration and allowed to cool down naturally. An unconfined pull-out test is carried out thereafter to obtain the post-fire bond behaviour. The investigations reported here were carried out to study two aspects: (i) influence of concrete cover on the residual bond behaviour of the rebar placed at the corner of the specimen, and (ii) influence of bond length on the residual bond behaviour of rebar placed at the edge or in the corner. The test results highlighted the strong influence of fire on bond behaviour, with approx. 50% reduction in the bond capacity and even stronger reduction in bond stiffness just after 30 min of standard fire exposure. This is attributable partly to the material degradation and partly to the high thermal gradients and associated cracking.

Behavior of steel box bridge girders subjected to hydrocarbon fire and bending-torsion coupled loading

This paper presents an experimental together with numerical investigation on behavior of steel box bridge girders under hydrocarbon (HC) fire and bending-torsion coupled loading conditions. Four test bridge girders fabricated utilizing single-box configured with twin-chamber supporting thin concrete slabs, taking into consideration sectional features and loading methods, were simultaneously subjected to HC fire exposure and bending-torsion coupled loading to analyze thermal and structural response. A numerical model established through program ANSYS, validated dependent on measured data generated from fire tests, was used to conduct a parametric analysis. Results show that significant discrepancies of temperature occur in mid-web and side-web of test bridge girders exposed to HC fire. Steel top flange has a significant influence on heat accumulation and transfer inside steel box, escape of water vapour in concrete slab and also fire resistance of steel box bridge girders. Deflection difference in transverse section of test bridge girders subjected to bending-torsion coupled loading gradually become predominant with fire exposure time. Test bridge girders without steel top flange experience a wide longitudinal crack in concrete slabs instead of excessive flexural deflection through entire fire exposure duration. Increasing longitudinal stiffeners in mid-web and bottom flange can effectively enhance fire resistance of steel box bridge girders. Timely evacuation of applied loads enforced on bridge girders during fire exposure can greatly delay deflection progression. The post-fire residual bearing capacity in test bridge girders can recover more than 80 % of initial bearing capacity after HC fire exposure. The experienced maximum temperature and fire exposure time has a predominant influence on post-fire recovery ability of steel box bridge girders under ventilation cooling conditions.

Progressive collapse resistance of RC frames subjected to localized fire

Fire is one of the accidental loads that can cause progressive collapse of buildings. However, the behavior of fire-exposed reinforced concrete (RC) frames to resist progressive collapse are still unclear. Therefore, a numerical study on the RC assembly based on the sequential thermal-mechanical coupling method is conducted. Fire effects on the failure mode, load-resistant capacity, and the evolution of load-resistant mechanisms of the RC frame are captured. The numerical results show that compressive arch action (CAA) and catenary action (CA) can develop in sequence for the specimens exposed to fire within a short fire duration of 30 min. The failure of the specimen is controlled by the fracture of beam rebars near the removed column. However, when the fire duration exceeds 60 min, the specimen is difficult to develop effective CA due to a decrease of over 80% in the tensile strength of the bottom reinforcement. The failure of the specimen is dominated by the fracture of the rebar at the cut-off point of the beam top rebar. Fire lasting for 30 min, 60 min, 90 min and 120 min results in a decrease of 41%, 72%, 77% and 78% in ultimate load, respectively. Increasing the span-depth ratio can upgrade the deformation capacity of the specimen, but it is adverse to the development of CAA. The effects of the reinforcement ratio on the failure mode, the ultimate load and deformation capacity are mild as the fire exposure duration increases.

Heating duration effects on post-fire structural steel mechanical properties

Post-fire mechanical assessment of steel structures is challenging due to the changes in mechanical properties from the heating and cooling phases of a fire. While the effects of cooling rate and temperature of exposure have been researched in depth, the effects of heating duration are not comprehensive. This paper investigates the effects of heating duration on post-fire A572 Gr. 50 steel mechanical properties over a temperature range of 500–800 °C for durations of 0.5 and 2.0 h. Specimens are subjected to tensile testing in accordance with ASTM A370, Vickers microhardness testing, and optical microscopy. The findings suggest that heating duration has an influence on the post-fire mechanical properties of steel at elevated temperatures (700, 800 °C). At these temperature exposures, retention of yield stress, retention of ultimate stress, and microhardness all decrease. Members subjected to 700 °C for 0.5 h have more retention in yield stress and microhardness compared to those exposed for 2.0 h, while the 800 °C conditions show little difference in mechanical properties between exposure times. The results of this study show that the duration of fire exposure is an important factor when estimating the mechanical properties of fire-exposed steels, in addition to the temperature and cooling rate.

Numerical simulation of blast resistance of reinforced concrete slabs under fire conditions

To study the blast resistance of reinforced concrete slabs under fire, the finite element software ABAQUS is used to simulate the static loading test of RC slabs under fire and the blast test of RC slabs at ambient temperature. After being validated, the FE model is employed to investigate the failure mechanism of RC slabs under the combined action of fire and blast using thermo-mechanical coupling technique. Moreover, the effects of fire exposure duration, scaled distance, and charge weight on the blast resistance of the RC slabs after fire are studied. The results show that blast results in the local shear failure in the center of the RC slab subjected to fire. Then, the whole floor slab undergoes flexural failure. With the increase of fire duration, the damage of RC slabs becomes more severe, and the plastic deformation gradually enables energy dissipation. The scaled distance and charge weight have the most significant influence on the failure mode and dynamic response of the RC slabs. The smaller the scaled distance, the more serious damage to the RC slabs. When the scaled distance is greater than 3 m/kg1/3, no damage occurs. The larger the charge weight, the more serious damage to the RC slabs.

Post-Earthquake Fire Punching Shear Behavior of GFRP-Reinforced Slab-Column Connections

It is not uncommon for reinforced concrete slab-column assembly to experience a punching brittle shear failure type under seismic loading. This research work numerically investigates the punching shear behavior of interior GFRP-reinforcedslab-column connections under post-earthquake fire. Two experimental results reported in the article were used for validation analysis using ANSYS nonlinear finite element software program. Further, parametric studies on influential variables such as fire exposure duration, concrete grade, slab thickness, fire exposed surface, and column aspect ratio were performed to get insight into the post-earthquake fire behavior of GFRP-reinforcedslab-column connections. Finite element analysis results showed decreasing fire exposure duration, enhancing grades of concrete, increasing slab thickness, minimizing fire exposure surfaces, and increasing column aspect ratio, which improved the punching shear capacity of GFRP-reinforced slab columns. Moreover, increasing slab thickness provided good performance against post-earthquake fire loading as compared to enhancing concrete grades in GFRP-reinforcedslab-column assemblies. The research concludes that it is crucial to take post-earthquake fire into account when designing structures to ensure no collapse safety design requirements.

Fire resistance tests on polypropylene-fiber-reinforced prestressed concrete box bridge girders

This paper presents an experimental study on fire behavior of polypropylene fiber prestressed concrete (PFPC) bridge girders subjected to localized hydrocarbon-fuel fire (mixed diesel oil and natural gas) and applied structural loading. The thermal responses, including temperature inside chamber, temperature within concrete and prestressing strands, were measured and analyzed throughout entire fire exposure duration. Further, structural responses, embracing mid-span deflection, effective prestress, polypropylene (PP) fiber concrete spalling, fire resistance, damage evolution and failure modes, attained from test were investigated in detail. The experimental results show that PP fiber can significantly release pressure of water vapor generated within high-strength concrete used in PFPC bridge girders, thus effectively enhancing spalling resistance of concrete in PFPC girders at elevated temperatures. The diaphragm can keep temperature inside chamber and also within top flange of PFPC box bridge girders steady for a period of time when temperature reaches 100 °C. However, the diaphragm has little effect on structural response of PFPC box bridge girders. The mid-span deflection increases sharply at final stage of fire exposure. Meanwhile, fracture of prestressing strands occurs and the effective prestress decreases suddenly towards final stage of fire exposure. Thereafter, PFPC bridge girders rapidly get to limit state dependent on rate of deflection, thus exhibiting a brittle failure characteristic. This failure of PFPC bridge girders can be prevented using reserved prestressing strands. PFPC bridge girders, designed as per under-reinforced girder at room temperature, vulnerably present failure characteristics of rare-reinforced girder under fuel fire exposure conditions.

Fire impact on mechanically failed graphite/epoxy composites

AbstractAircraft crashes often initiate or accompany fire incidents. Post‐crash fires, in particular, can mask or destroy critical fractographic failure features necessary for accident reconstruction. As a first step in developing a coherent strategy for composite aircraft post‐crash forensic analysis, a series of vertical flame tests were performed on mechanically failed Cytec T40‐800/Cycom® 5215 graphite/epoxy unnotched compression, short beam strength, and in‐plane shear specimens. Visual inspection and scanning electron microscopy were used to examine the specimens fracture surfaces before and after fire testing. The fire‐induced damage included matrix decomposition, melt dripping, char, soot, delamination, and residual thickness increases. The composite thermal degradation was significantly influenced by the specimen stacking sequence, the fracture surface morphology, and the total available free surface area. In addition, microscopic inspection showed that char layers impeded heat conduction and oxygen transfer to the interior of the specimens resulting in less thermal damage to the underlying plies. Moreover, burned specimens with more available free surface area sustained more thermal degradation and fire combustion damage for a given fire exposure duration. Exposed fiber bundles from the fracture surfaces were susceptible to severe thinning and thermal oxidation, which destroyed critical fractographic failure features necessary for accident reconstruction.

Seismic performance evaluation of steel and GFRP reinforced concrete shear walls at high temperature

Fire-induced structural damage to the seismic performance of reinforced concrete shear walls is critical in the event of a fire-earthquake scenario. However, only few researchers have studied the seismic performance of reinforced concrete shear walls at high temperatures. This study focuses on the seismic performance of fiber reinforced concrete shear walls at high temperatures by using finite element (FE) software, ABAQUS. The experimental test available in a literature on seismic behavior of shear walls exposed to fire and thermal properties of glass fiber reinforced polymer (GFRP) bars were used to validate the FE model and showed good agreement and thus used in the simulation.The FE results showed that exposure of RC shear wall to fire reduced the strength of the wall. The strength of walls at the maximum applied drift of 3.2% with concrete cover thicknesses of 20 mm, 25 mm, and 30 mm was dropped by about 70%, 76%, and 85% of the reference shear wall, respectively. Similarly, the strength of RC walls was reduced by about 80%, 75%, and 68% of the reference shear wall for the duration of fire exposure of 30 min, 60 min, and 120 min, respectively. Additionally, the strength of walls due to one side, two sides, or all sides’ exposure to fire was decreased by about 68%, 56%, and 50% of the reference shear wall, respectively. It can generally be concluded that the fire exposure sides has largely affected the strength of the shear wall compared to the other parameters and GFRP bars were more sensitive to temperature than steel bars.

Effect of fire-induced restraint forces on fire behavior of reinforced and prestressed concrete beams

This paper presents results from a set of numerical studies on the effect of fire-induced restraint forces on the response of prestressed concrete (PC) beams. The main parameters studied are the effect of cross-sectional shape, support conditions, and level of prestress. The numerical studies are conducted using a validated three-dimensional (3D) finite-element (FE) based numerical model which accounts for critical governing factors such as magnitude and location of restraint forces, cracking and crushing of concrete, material, and geometric nonlinearity, and spalling. Especially, the model accounts for varying fire-induced restraint forces throughout fire exposure using a new efficient spring idealization framework for connections. The effect of fire-induced restraint forces on the fire response of PC beams is compared with equivalent RC beams to identify key differences in the fire behavior of PC and RC beams. Results from the advanced numerical studies show that significant restraint forces develop in PC and RC beams under fire exposure and these forces vary with fire exposure duration. Further the results show that the fire-induced restraint forces significantly alter the structural response of the beam.

Influence of Fire-Flame Duration and Temperature on the Behavior of Reinforced Concrete Beam Containing Water Absorption Polymer Sphere; Numerical Investigation

One of the most important parameters determining structural members' durability and strength is the fire flame's influence and hazard. Some engineers have advocated using advanced analytical models to predict fire spread impact within a compartment and considering finite element models of structural components to estimate the temperatures within a component using heat transfer analysis. This paper presented a numerical simulation for a reinforced concrete beam’s structural response in a case containing Water Absorbing Polymer Spheres (WAPS) subjected to fire flame effect. The commercial finite element package ABAQUS was considered. The relevant geometrical and material parameters of the reinforced concrete beam model at elevated temperature are first suggested as a numerical model. After that, the suggested numerical model was validated against the experimental tests conducted in this study. The validated numerical model was used to conduct a parametric study to investigate the effects of two important parameters on the structural behavior after being exposed to fire flame. The effect of burning temperatures (500, 600, and 700) oC, as well as the influence of fire duration (1 and 2) hours, were included. The experimental program validation requirement comprised four self-compacted reinforced concrete beams each of the same geometric layout (150x200x1500) mm, reinforcing details, and compressive strength (fc'=50 MPa). Four percentages of (WAPS) were considered (0, 1, 2, and 3)%. The specimens were exposed to a fire flame with a steady-state temperature (500°C), a rising rate compatible with ASTM-E119, a one-hour duration, and a sudden cooling procedure. A static (two-point) load was applied to the burned beams. Through the assessed numerical model, the numerical analysis offered by the WAPS ratio effect was carried out for the reinforced concrete beam under the effect of static load. The findings revealed that the WAPS ratio substantially impacted structural behavior. The numerical model's results were in reasonable agreement with the experimental results. Concerning the fire exposure duration (two hours) at 500 oC, the specimens containing a ratio (3%) of WAPS improved the ultimate load and the ultimate deflection by about (46.63 and 72.24)%, respectively. The highest percentage variation of the absorbed energy at failure load was also detected in the ratio (3%) to be (139.43) %. As for the hardening concrete properties (compressive strength, splitting tensile strength, and modulus of elasticity), the residual strength was (61.06, 48.87, and 32.00)%, respectively. Regarding the steady-state burning temperature (500, 600, and 700)oC for a one-hour duration, the specimens with a ratio of (3%) WAPS improved the ultimate load by about (40.70, 62.00, and 40.76)%, respectively, corresponding to zero percentage of WAPS. The residual compressive strength, splitting tensile strength, and modulus of elasticity were (72.40, 56.12, and 43.78)%, (74.36, 56.50, and 44.79)%, and (45.23, 36.57, and 28.94)%, respectively.

Structural integrity of composite floors in fire: A comparison of two large-scale experiments with varying slab reinforcement

This paper presents a comparison of two compartment fire experiments performed on the 9.1 m × 6.1 m composite floors using a full-scale two-story steel gravity frame to study the influence of slab reinforcement on the overall structural integrity. The floor specimens were designed to achieve a 2-h fire rating but had dissimilar slab reinforcement. The Test #1 specimen had steel wire reinforcement of 60 mm2/m width as the minimum permitted in the United States practice whereas the Test #2 specimen was reinforced with deformed steel bars (230 mm2/m) determined by incorporating tensile membrane action. The Test #1 specimen exhibited mid-panel slab integrity failure before reaching the specified fire rating period. However, the Test #2 specimen exhibited much smaller concrete cracks until it was heated up to 131 min and retained the post-fire residual strength at least two times greater than the design demand at ambient temperature. This unique large-scale testing demonstrated that the appropriate slab reinforcement scheme can delay the vertical deflection of the heated composite floor and maintain the structural integrity at large vertical displacements over a longer duration of fire exposure.

Experimental investigation on the effect of open fire on the tensile properties and damage evolution behavior of granite

The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process of rock. The microstructures of the treated granites were observed by scanning electron microscope (SEM). The results showed that the fire duration and cooling treatment have a significant effect on the P-wave velocity, static nominal tensile strength, and dynamic nominal tensile strength of granite. These characteristics decrease rapidly during 0 to 10 min, and slowly decrease after 20 min. Compared to the air-cooling treatment, the water-cooling treatment has greater damage to the heated granite. To better understand the results, the rapid heating process of open fire heating was simulated using Abaqus software. The results reveal that there is a thinner compressive stress zone at the bottom of the specimen, and there is a large zone in the middle of the sample with higher tensile stress. The crack extension would be expanded due to high tensile stress, leading to the reduction of the tensile strength of the rock. This paper aims to better predict the degree of damage of rock materials after actual fire, as well as preliminarily explore the effect of the fire exposure duration and fire extinguishing method on the tensile properties of rock.

Modeling the behavior of CFRP-strengthened RC slabs under fire exposure

This paper presents the development of a numerical model that simulates the fire response of reinforced concrete (RC) slabs externally strengthened with carbon fiber-reinforced polymer (CFRP)laminates using two different techniques, externally bonded (EB) and near-surface mounted (NSM). A three-dimensional (3D) nonlinear finite element (FE) model is developed to predict the thermal and structural behavior of strengthened RC slabs subjected to fire. The model incorporates temperature-dependent thermal and mechanical properties of concrete, steel reinforcement, and CFRP, as well as mechanical bond interaction between CFRP and concrete interfaces. The predicted temperature profiles, ultimate loads, and midspan deflections are compared with previously published experimental data. Results from the proposed model show a good correlation with the experimental data throughout the fire exposure duration. The validated model can be adapted to conduct parametric studies intended to inspect the effect of important factors that influence the behavior of strengthened RC slabs under fire.

EVALUATION OF FIRE RESISTANCE OF FIRE PROTECTED STEEL STRUCTURES BY CALCULATION AND EXPERIMENTAL METHOD

Based on the developed geometric, physical, computer and finite element model, the fire resistance of fire-resistant steel structures was evaluated by calculation and experimental method. The adequacy of the developed computational-experimental method for assessing the fire resistance of fire-resistant steel structures in assessing the fire resistance of a fire-resistant I-beam steel column was verified. The results of tests for fire resistance of steel columns with fire-retardant coating at standard temperature of the fire without the load applied to them (temperature in the furnace, temperature in certain places on the surface of fire-retardant steel columns, the behavior of the investigated fire-retardant coating). The analysis of tests on fire resistance of fire-resistant steel columns exposed to fire at standard temperature (temperature in the furnace, temperature in places of measurement of temperature on a surface of columns, behavior of a fire-retardant covering) is carried out. A computer model of the «steel column – reactive flame retardant coating» system has been built for numerical simulation of non-stationary heating of such a system. Simulation of non-stationary heating of the system «steel column – fire-retardant coating» in the software package FRIEND with the specified parameters (geometric model, thermal effects, initial and boundary conditions, properties of system materials). The reliability of the results of numerical modeling with real experimental data on the duration of fire exposure at the standard temperature of the fire to reach the critical temperature of steel. Based on the comparison of experimental results and numerical simulations, a conclusion is made about the adequacy of the developed model to the real processes that occur when heating fire-retardant steel columns without applying a load under fire conditions at standard fire temperature. The efficiency of the proposed calculation and experimental method for assessing the fire resistance of fire-resistant steel structures has been confirmed.

Study on shear performance of notched connections for glulam-concrete composite beams under fire

Shear connection guarantees that the timber beam and concrete slab of a composite beam interact effectively. Shear connection performance markedly affects the fire resistance of timber-concrete composite beams. Shear connection experiments under fire are uncommon in comparison to those conducted at ambient temperature, and there have been few previous investigations on the shear performance of notched connections under fire. Six specimens were sheared at ambient temperature and ten specimens were sheared at elevated temperature in this study to determine the shear behavior of notched connections exposed to ISO fire. The length of the notch connection and the duration of fire exposure are two factors that may influence the shear behavior of the connections. With the increase of fire time, the shear bearing capacity and slip modulus of notched connections decreased. As notch length increased from 150 mm to 250 mm, the failure modes of shear specimens under fire changed from shear failure of concrete in the notch to compression failure of timber near the notch. Experimental results and finite element thermal analysis results were used to establish an analytical model for the shear bearing capacity of notched connections for glulam-concrete beams under ISO fire exposure.