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This study aims at investigating the effect of bolt hole-making processes on the post-fire behavior of S235 steel plates.

A total of nine steel plates with a single bolt hole are tested. The single bolt holes are fabricated using three different hole-making processes: drilling, waterjet and plasma. Among the nine steel plates, three fabricated specimens are control specimens and are tested at ambient temperature. The six remaining steel plates with a single bolt hole are subjected to a complete heating-cooling cycle and then monotonically loaded until failure. The six fabricated specimens are first heated up to two different temperatures 800 and 925 °C, and then cooled back to the ambient prior to loading.

The results show that after being exposed to post-fire temperatures (800 and 925 °C), the maximum decrease in strength of the S235 steel plate was 6% (at 925 °C), 14% (at 925 °C) and 22% (at 800 °C) when compared to the results of ambient specimens for waterjet, drilled and plasma bolt holes, respectively. For post-fire temperature tests, drilled and waterjet bolt hole-making processes result in having approximately the same load-displacement response, and both have larger strength and ductility than those obtained using plasma cutting.

This study provides preliminary data to guide the steel designers and fabricators in choosing the most suitable hole-making process for fire applications and to quantify the post-fire reduction in capacity of S235 plates.

Top-seat angle connection is known as one of the usual uncomplicated beam-to-column joints used in steel structures. This article investigates the fire performance of welded top-seat angle connections.

A finite element (FE) model, including nonlinear contact interactions, high-temperature properties of steel, and material and geometric nonlinearities was created for accomplishing the fire performance analysis. The FE model was verified by comparing its simulation results with test data. Using the verified model, 24 steel-framed top-seat angle connection assemblies are modeled. Parametric studies were performed employing the verified FE model to study the influence of critical factors on the performance of steel beams and their welded angle joints.

The results obtained from the parametric studies illustrate that decreasing the gap size and the top angle size and increasing the top angles thickness affect fire behavior of top-seat angle joints and decrease the beam deflection by about 16% at temperatures beyond 570 °C. Also, the fire-resistance rating of the beam with seat angle stiffener increases about 15%, compared to those with and without the web stiffener. The failure of the beam happens when the deflections become more than span/30 at temperatures beyond 576 °C. Results also show that load type, load ratio and axial stiffness levels significantly control the fire performance of the beam with top-seat angle connections in semi-rigid steel frames.

Development of design methodologies for these joints and connected beam in fire conditions is delayed by current building codes due to the lack of adequate understanding of fire behavior of steel beams with welded top-seat angle connections.

Elevated temperature material properties are essential in predicting structural member's behavior in high-temperature exposures such as fire. Even though experimental methodologies are available to determine these properties, advanced equipment with high costs is required to perform those tests. Therefore, performing those experiments frequently is not feasible, and the development of numerical techniques is beneficial. A numerical technique is proposed in this study to determine the temperature-dependent thermal properties of the material using the fire test results based on the Artificial Neural Network (ANN)-based Finite Element (FE) model.

An ANN-based FE model was developed in the Matlab program to determine the elevated temperature thermal diffusivity, thermal conductivity and the product of specific heat and density of a material. The temperature distribution obtained from fire tests is fed to the ANN-based FE model and material properties are predicted to match the temperature distribution.

Elevated temperature thermal properties of normal-weight concrete (NWC), gypsum plasterboard and lightweight concrete were predicted using the developed model, and good agreement was observed with the actual material properties measured experimentally. The developed method could be utilized to determine any materials' elevated temperature material properties numerically with the adequate temperature distribution data obtained during a fire or heat transfer test.

Temperature-dependent material properties are important in predicting the behavior of structural elements exposed to fire. This research study developed a numerical technique utilizing ANN theories to determine elevated temperature thermal diffusivity, thermal conductivity and product of specific heat and density. Experimental methods are available to evaluate the material properties at high temperatures. However, these testing equipment are expensive and sophisticated; therefore, these equipment are not popular in laboratories causing a lack of high-temperature material properties for novel materials. However conducting a fire test to evaluate fire performance of any novel material is the common practice in the industry. ANN-based FE model developed in this study could utilize those fire testing results of the structural member (temperature distribution of the member throughout the fire tests) to predict the material's thermal properties.

Modern complex integrated circuits require more input/output connections and operate at faster switching speeds and higher power levels than was the case before LSI and VLSI devices. As a result, there is a need for packages with high electrical conductivity, low dielectric constant, high thermal conductivity, precise line resolution and low unit cost. Ideally, it should also be possible to include resistors and for the package to be manufactured in‐house for maximum control. Multilayer printed circuit boards, complex multilayer hybrid circuits and high temperature co‐fired ceramic packages have been used to accomplish the interconnection of complex ICs. A new technology has been developed which combines the benefits of thick film with the processing advantages of co‐fired ceramic. The thick film process begins with a bare substrate, usually 96% alumina, upon which gold, silver alloy or copper metallisation, and screen‐printable dielectric paste are applied. Processing is a series of printing and firing operations; the firing temperature is usually between 800°C and 1000°C. Interconnecting vias are typically formed by screen printing and are usually a minimum of 250 ?m (10 mil) in diameter. The high temperature co‐fired approach uses no substrate. Printing of tungsten, molybdenum or molymanganese metallisation is carried out on alumina tape dielectric. The vias are formed by mechanical punching and are typically a minimum of 200 ?m (8 mil) in diameter. A single firing is performed in a special atmosphere, usually at 1500°C. This paper describes a new materials system which consists of a tape dielectric and gold, silver and silver/palladium inner layer and via fill conductor compositions. Circuits and packages made with the system are fired in an air atmosphere in standard thick film furnaces and are compatible with other conventional thick film materials. The process for making these parts is described and critical process parameters are identified. The results of reliability testing under temperature, humidity and bias are discussed and supporting microstructural analysis is presented.

This paper aims to present the details of a study undertaken to develop an energy-based time equivalent approach to obtain the fire resistance ratings (FRRs) of light gauge steel frame (LSF) walls exposed to realistic design fire curves.

The energy-based time equivalent method was developed based on the performance of a structural member exposed to a realistic design fire curve in comparison to that of the standard fire time – temperature curve. The FRR predicted by the energy-based method for LSF wall configurations exposed to both rapid and prolonged fires were compared with those from fire design rules and finite element analyses (FEA).

The proposed energy method can be used to obtain the FRR of LSF walls in case of prolonged fires and cannot be used for rapid fires as the computed FRRs were higher than the results from FEA and fire design rules due to the influence of thermal bowing and its magnification effects at a high temperature gradient across the studs for rapid fires.

The energy-based time equivalent method was developed based on equal fire severity principles. Three different wall configurations were considered and exposed to both rapid and prolonged fires. The FRR obtained from the energy-based method were compared with fire design rules and FEA results to assess the use of the energy-based method to predict the FRR of LSF walls.

The Reinforced Concrete(RC) elements are known to perform well during exposure to elevated temperatures. Hence, RC elements are widely used to resist the extreme heat developing from accidental fires and other industrial processes. In both of the scenarios, the RC element is exposed to elevated temperatures. However, the primary differences between the fire and processed temperatures are the rate of temperature increase, mode of exposure and exposure durations. In order to determine the effect of two heating modalities, RC beams were exposed to processed temperatures with slow heating rates and fire with fast heating rates.

In the present study, RC beam specimens were exposed to 200 °C, to 800 °C temperature at 200 °C intervals for 2 h' duration by adopting two heating modes; Fire and processed temperatures. An electrical furnace with low-temperature increment and a fire furnace with standard time-temperature increment is adapted to expose the RC elements to elevated temperatures.

It is observed from test results that, the reduction in load-carrying capacity, first crack load, and thermal crack widths of RC beams exposed to 200 °C, and 600 °C temperature at fire is significantly high from the RC beams exposed to the processed temperature having the same maximum temperature. As the exposure temperature increases to 800 °C, the performance of RC beams at all heating modes becomes approximately equal.

In this work, residual performance, and failure modes of RC beams exposed to elevated temperatures were achieved through two different heating modes are presented.

The paper aims to give an insight into the behaviour of reinforced concrete columns during and after the cooling phase of a fire. The study is based on numerical simulations as these tools are frequently used in structural engineering. As the reliability of numerical analysis largely depends on the validity of the constitutive models, the development of a concrete model suitable for natural fire analysis is addressed in the study.

The paper proposes theoretical considerations supported by numerical examples to discuss the capabilities and limitations of different classes of concrete models and eventually to develop a new concrete model that meets the requirements in case of natural fire analysis. Then, the study performs numerical simulations of concrete columns subjected to natural fire using the new concrete model. A parametric analysis allows for determining the main factors that affect the structural behaviour in cooling.

Failure of concrete columns during and after the cooling phase of a fire is a possible event. The most critical situations with respect to delayed failure arise for short fires and for columns with low slenderness or massive sections. The concrete model used in the simulations is of prime importance and the use of the Eurocode model would lead to unsafe results.

The paper includes implications for the assessment of the fire resistance of concrete elements in a performance‐based environment.

The paper provides original information about the risk of structural collapse during cooling.

This paper aims to investigate the predicted temperature behaviour of the protected cellular steel beam (CSB) with circular web openings at elevated temperature through finite element simulation.

Temperature development along the CSB were analysed and used for parametric investigation. In addition, this research paper investigates the novelty application of various intumescent coating thicknesses covering the whole CSB to cut down the temperature development along the beam section.

From the simulation outcomes, it shows that intumescent coating has a significant effect in reducing the temperature development along the CSB section. Thicker intumescent coating contributes to a higher temperature drop at the bottom tee section than the upper tee section.

The use of structural CSB has gained popularity among engineers and architects. This type of beam allows serviceability ducts and pipes to pass through the main steel web section under the flooring system, thus providing larger headroom for designers. Nevertheless, in any structural steel building, it is highly risky for CSB to be exposed to fire hazard if it were triggered accidentally. To mitigate and reduce fire exposure risk which might compromise the strength and stiffness of CSB, a passive fire protection is proposed to minimise the risk. One of the common passive fire protection materials used for steel beam section is intumescent coating. Intumescent coating is by far the cheapest solution to protect CSB as compared to other passive fire protection system. Intumescent coating can absorb some portion of heat exposure which subsequently translates a lower temperature development along the CSB section.

Light-Gauge Steel Frame (LSF) structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel lipped channel sections negative fire performance, cavity insulation materials are utilized in the LSF configuration to enhance its fire performance. The applicability of lightweight concrete filling as cavity insulation in LSF and its effect on the fire performance of LSF are investigated under realistic design fire exposure, and results are compared with standard fire exposure.

A Finite Element model (FEM) was developed to simulate the fire performance of Light Gauge Steel Frame (LSF) walls exposed to realistic design fires. The model was developed utilising Abaqus subroutine to incorporate temperature-dependent properties of the material based on the heating and cooling phases of the realistic design fire temperature. The developed model was validated with the available experimental results and incorporated into a parametric study to evaluate the fire performance of conventional LSF walls compared to LSF walls with lightweight concrete filling under standard and realistic fire exposures.

Novel FEM was developed incorporating temperature and phase (heating and cooling) dependent material properties in simulating the fire performance of structures exposed to realistic design fires. The validated FEM was utilised in the parametric study, and results exhibited that the LSF walls with lightweight concrete have shown better fire performance under insulation and load-bearing criteria in Eurocode parametric fire exposure. Foamed Concrete (FC) of 1,000 kg/m3 density showed best fire performance among lightweight concrete filling, followed by FC of 650 kg/m3 and Autoclaved Aerated Concrete (AAC) 600 kg/m3.

The developed FEM is capable of investigating the insulation and load-bearing fire ratings of LSF walls. However, with the availability of the elevated temperature mechanical properties of the LSF wall, materials developed model could be further extended to simulate the complete fire behaviour.

LSF structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel-lipped channel sections negative fire performance, cavity insulation materials are utilised in the LSF configuration to enhance its fire performance. The lightweight concrete filling in LSF is a novel idea that could be practically implemented in the construction, which would enhance both fire performance and the mechanical performance of LSF walls.

Limited studies have investigated the fire performance of structural elements exposed to realistic design fires. Numerical models developed in those studies have considered a similar approach as models developed to simulate standard fire exposure. However, due to the heating phase and the cooling phase of the realistic design fires, the numerical model should incorporate both temperature and phase (heating and cooling phase) dependent properties, which was incorporated in this study and validated with the experimental results. Further lightweight concrete filling in LSF is a novel technique in which fire performance was investigated in this study.

Most of the industrial buildings which are designed to moderate loads are constructed using light gauge cold-formed steel (CFS) sections. Residual mechanical properties of CFS sections exposed to elevated temperature need to be investigated as it is necessary to predict the deterioration of elements to avoid failure of the structure or its elements. Also, it would be helpful to decide whether the structural elements need to be replaced or reused. The use of fire-resistant coatings in steel structures significantly reduces the cost of repairing structural elements and also the probability of collapse. This study investigates the effect of fire-resistant coating on post-fire residual mechanical properties of E350 steel grade.

In this study, an attempt has been made to evaluate the residual mechanical properties of E350 steel. A tensile coupon test was performed for the extracted specimens from the exposed CFS section to determine the mechanical properties. Four different fire-resistant coatings were selected and the sections were coated and heated as per ISO 834 fire temperature curve in the transient state for time durations of 30 minutes (821°C), 60 minutes (925°C), 90 minutes (986°C), and 120 minutes (1,029°C). After the exposure, all the coupon specimens were cooled by either ambient conditions (natural air) or water spraying before conducting the tension test on these specimens.

At 30 min exposure, the reduction in yield and ultimate strength of heated specimens was about 20 and 25% for air and water-cooled specimens compared with reference specimens. Specimens coated with vermiculite and perlite exhibited higher residual mechanical property up to 60 minutes than other coated specimens for both cooling conditions. Generally, water-cooled specimens had shown higher strength loss than air-cooled specimens. Specimens coated with vermiculite and perlite showed an excellent performance than other specimens coated with zinc and gypsum for all heating durations.

As CFS structures are widely used in construction practices, it is crucial to study the mechanical properties of CFS under post-fire conditions. This investigation provides detailed information about the physical and mechanical characteristics of E350 steel coated with different types of fire protection materials after exposure to elevated temperatures. An attempt has been made to improve the residual properties of CFS using the appropriate coatings. The outcome of the present study may enable the practicing engineers to select the appropriate coating for protecting and enhancing the service life of CFS structures under extreme fire conditions.