Fire Design Research Articles

Application Analysis of Artificial Intelligence Technology in Electrical Engineering Teaching

This article combines the characteristics of artificial intelligence technology and educational technology to realize the possibility of application in electrical automatic control systems, and applies artificial intelligence and educational technology to electrical engineering examples such as monitoring fire alarm open circuit design and smoke box appearance inspection in power transformation and distribution systems. Analyze the impact of artificial intelligence on electrical automation technology. The research results show that artificial intelligence and education can make electrical automation technology have the characteristics of simplification, distribution, informatization, diversity, flexibility, continuity, real-time and control complexity. Use artificial intelligence technology and educational technology to effectively analyze and process electrical engineering related parameters and data, reduce the use of lines and transformers, simplify work procedures, reduce error rates, save manpower, material resources and costs, and improve the accuracy of automatic control.

Heat transfer mechanism and emergency operating speed of moving train fires in a metro tunnel

The primary strategy for a burning train in metro tunnels is to drive it out of the tunnel, or to the station or safe area ahead. However, the heat transfer mechanism and the emergency operating speed of moving train fires in tunnels have not been addressed. In this study, a 1:10 train-tunnel model was designed to conduct a series of moving model experiments. The results show that with the increasing train speed in tunnels, the flame height decreases, the flame width and length first increase and then decrease, and the flame tilt angle increases. The maximum temperature at the train top increases by 81.7 % when the train speed increases from 2 to 6 m/s. A piecewise model is proposed to predict the maximum temperature at the train top. The maximum temperature rise at the tunnel ceiling is 17.4 K and exponentially decreases with the train speed, posing a limited threat to the tunnel structure. The convective heat flux received by the train accounts for 82.1 %–94.4 %. The heat transfer between the train, tunnel and flame is codetermined by the train-tunnel aerodynamic effect and fuel-rich zone. The emergency operating speed of the train is suggested to be 22.8 km/h when the heat release rate is 7.5 MW. This study innovatively reveals the combustion behavior of moving train fires in a metro tunnel and proposes guidelines for determining the emergency operating speed of burning trains. The results can provide references for the fire safety design and running capacity improvement of metro trains.

Experimental study on fire resistance of high strength Q960 steel columns under axial compression

In order to obtain the mechanical behavior of H-shaped high-strength Q960 steel column under axial compression in fire, the bearing capacity tests of two Q960 steel columns at ambient temperature and fire resistance tests of six Q960 steel columns at elevated temperature were carried out. By considering different slenderness ratios, load ratios, and heating rates of the test columns, the furnace temperature, column temperature, lateral displacement, and axial displacement were measured and recorded. Then, critical temperature, fire resistance, and failure mode of the columns were obtained. The thermal-mechanical coupling analysis model for the Q960 steel column was established by using ABAQUS finite element analysis software. After verifying the accuracy of the model, parameter analysis was carried out to investigate the effects of load ratio, slenderness ratio, geometric imperfection, thermal creep, residual stress, and steel strength on the fire resistance of steel columns. Based on the test data and analysis results, a fire resistance design method for high-strength Q960 steel columns under axial compression is proposed.

Anti-sliding performance of parallel wire strand clamps at elevated temperatures

This study investigated the influence of temperature on the anti-sliding performance of prestressed parallel wire strand clamps (PWSCs) through experiments and numerical analyses. The ultimate anti-sliding resistance of the clamps at different temperatures was obtained through steady-state experiments, and formulae for calculating high-temperature reduction factors of anti-sliding resistance were proposed. When the temperature reaches 400 °C, the ultimate anti-sliding resistance that the cable clamps can withstand is only 20.8% of the ambient temperature. The function between the ultimate fire resistance time of the PWSC and thrusting load level was proposed under ISO-834 heating conditions through transient-state experiments. It was found that the higher the thrusting load level, the shorter the fire resistance time that the PWSC can withstand. When the load level is 0.9Ffc,20, the fire resistance time of the specimen is only 38.1% of that under 0.3Ffc,20. The bolt pretension loss process of PWSCs under high temperatures was studied through numerical simulations of steady-state experiments. At 400 °C, the pretension of the bolt was only 67.3% of that at 20 °C. On this basis, a refined calculation formula for the high-temperature bolt pretension loss was proposed on the basis of the numerical results. The findings of this research can further improve the fire resistance design of prestressed steel structures.

Study on anti-sliding performance of cable clamps under and after elevated temperature

Cable clamps are key joints in building cable structures and are vulnerable positions in fire accidents. Currently, there is little research on the elevated-temperature mechanical properties of cable clamps. Therefore, the high-temperature mechanical properties of cable clamps were investigated in this study. First, anti-sliding tests at room temperature, elevated temperatures, and after elevated temperatures were conducted for the cable clamps, and the pushing force-sliding displacement curves of the cable clamps were obtained. The relaxation law of the bolt tightening force and the anti-sliding performance of the cable clamps were studied. The results indicated that when the temperature exceeded 300 °C, the anti-sliding performance of cable clamps started to decline. When the temperature reached 500 °C, the anti-sliding bearing capacity of cable clamp was approximately 27 % of that at room temperature. For cable clamps after high-temperature treatment, when the heat treatment temperature exceeded 300 °C, the anti-sliding bearing capacity was approximately 50 % of that at room temperature. Therefore, based on the ABAQUS finite element software, simplified and refined models of the cable clamps are proposed to simulate the sliding process of locked coil wire rope clamps. The effects of material properties and non-uniform expansion on the anti-sliding performance of cable clamps were studied, which provides a theoretical basis for the fire resistance design of building cable structures.

Blockchain-based fire safety inspection analysis and system design

Today's buildings usually rely on various firefighting equipment for warning, often neglecting the importance of safety inspections. Most fires occur due to the usual weak awareness of fire prevention. If regular and strict safety inspections are carried out according to the regulations of fire departments will greatly reduce the occurrence of fires. Safety inspections in each unit include fire supervisors from the government and inspectors from relevant maintenance agencies, and these inspectors usually use paper reports to record the safety inspection work. This traditional practice leaves hidden problems for unresolved and important issues, including data integrity and tamperability, which will directly lead to difficulties in tracing responsibilities based on these data after an accident. Therefore, this paper proposes a de-neutralized, blockchain-based traceability system for a fire safety inspection. Blockchain technology has the characteristics of traceability, decentralization, consensus trust, and hard to tamper, which can be combined with this system. The system's core mainly adopts the Hyperledger Fabric consortium blockchain framework, configured to build a blockchain network. The network is organized with three organizations: government, unit, and maintenance agency, and smart contracts are written to process safety inspection data, thus guaranteeing the sharing of fire inspection information as well as traceability.

Performance-based design for structures in fire: Advances, challenges, and perspectives

The Performance-Based Design approach provides a goal-oriented process to support safe, innovative, and resilient structural fire designs. However, adoption of this approach requires both a rigorous framework and appropriate analysis tools to assess the expected performance of structures in fire. The objective of this paper is to provide an overview of the Performance-Based Design approach, including the process and its specific elements, applied to structures in fire. First, the value of the approach is illustrated through a review of case studies. Then, the process is described with identification of the role of the structural fire engineer. Recent research in methods to enable the evaluation of the structural fire performance, conducted within the author's group at Johns Hopkins University, is discussed. Issues addressed include the coupling between the fire and thermal-structural models, the characterization of the material behavior at elevated temperature, numerical modeling of structures subjected to fire, probabilistic risk assessment, and cost-benefit analyses. The paper concludes with a discussion of some challenges and perspectives for the future of performance-based structural fire design.

Cross-sectional behaviour of QN1803 high-strength stainless steel I-section stub columns in fire

QN1803 is a novel high-strength stainless steel with low nickel. Compared to traditional stainless steel, QN1803 high-strength stainless steel has higher yield strength and lower cost without compromising anti-corrosion properties, thus leading to a wide application prospect. This paper focuses on the cross-sectional behaviour of QN1803 high-strength stainless steel I-section stub columns in fire. A total of eight stub column tests were finished, of which six were elevated temperature tests and two were room temperature control tests. Room temperature and elevated temperature tensile coupon tests were conducted to obtain the material properties of the QN1803 high-strength stainless steel. The design methods of European fire design standard EN 1993-1-2 and the latest fire design methods proposed by Xing et al., which will be incorporated into the upcoming version of EN 1993-1-2, were evaluated in terms of accuracy and safety for the fire design of QN1803 high-strength stainless steel I-section stub columns. It was found that most ultimate cross-sectional resistances of QN1803 high-strength stainless steel I-section stub columns predicted by the design rules of European fire design standard EN 1993-1-2 were unsafe, while the ultimate cross-sectional resistances predicted by the design methods of Xing et al. were safe and accurate for the tested QN1803 high-strength stainless steel I-section stub columns.

Experimental study on thermal behaviors of two-layered functionally graded concrete slabs subjected to fire

In order to improve structural thermal performances, this paper designed a two-layered functionally graded concrete (FGC) slab composed of an ultra-high performance concrete (UHPC) layer and a lightweight aggregate concrete (LWAC) layer. UHPC layers are used as structural layers to bear loads while LWAC layers are used for thermal insulation. Fire tests were conducted to investigate the fire resistance behaviors of the FGC slabs with different LWAC thicknesses under the ISO834 heating regime while homogeneous UHPC and normal concrete (NC) slabs were prepared as a contrast. The experimental results revealed that the LWAC could significantly reduce the temperature transferred to UHPC layers, where the interfacial temperatures of FGC slabs with 40 mm and 30 mm thick LWAC layers were 197 °C and 325 °C respectively. Meanwhile, the maximal mid-span deflections ranged from 26.1 mm to 31.5 mm respectively, approximately 55%-65% lower than those of homogeneous material specimens. Besides, FGC slabs presented good explosive spalling resistance, no delamination or debonding occurred at interfacial regions, and LWAC layers adhered to UHPC layers in the form of “multi-point attachment”. The studies provided a solution to the fire resistance design of reinforced concrete structures under high temperature based on the structural level, and the thickness of LWAC layers was optimized by finite element analyses.

Stability and design of stainless steel hollow section columns at elevated temperatures

This paper investigates the stability and design of stainless steel circular, elliptical, square and rectangular hollow section (CHS, EHS, SHS and RHS) columns at elevated temperatures. Nonlinear shell finite element models are employed to conduct comprehensive parametric studies whereby extensive benchmark structural performance data on the behaviour and resistance of stainless steel hollow section columns at elevated temperatures is generated. In total, 26,760 cold-formed and hot-rolled austenitic, duplex and ferritic stainless steel CHS, EHS, SHS and RHS columns at elevated temperatures are taken into account, considering various member slendernesses, cross-section geometries, cross-section slendernesses and elevated temperature levels. New flexural buckling design rules are put forward for stainless steel hollow section columns in fire, which consistently considers the elevated temperature strength at 2% total strain f2,θ as the reference material strength for all cross-sections classes. The accuracy, safety and reliability of the proposed new design rules are assessed for a wide range of cases. Comparisons are also made against the results obtained through the column fire design rules of the European structural steel fire design standard EN 1993-1-2 [1]. It is demonstrated that the proposed new design rules furnish more accurate, safe-sided and reliable flexural buckling resistance predictions for stainless steel hollow section columns at elevated temperatures relative to the column fire design provisions of EN 1993-1-2 [1].

Design and Development of Fire Fighting Robot with Live Streaming

Design and Development of Fire Fighting Robot with Live Streaming

Smart fire detection analysis in complex building floorplans powered by GAN

Ceiling-mounted fire service systems are the most widely used provisions to ensure building fire safety. Current design distribution of fire detectors is based on semi-empirical correlations derived from open-floor fire experiments, but building floorplan affects their activation. This work develops a generative adversarial network (GAN) model to achieve accurate and real-time fire detection analysis for buildings with complex floorplans. A numerical fire database with hundreds of floorplans, fire locations and ceiling heights is established to train the GAN model. The pre-trained model can recognize geometric characteristics and reveal hidden fire dynamics laws. Given any building floorplan and fire detector distribution, the model can predict ceiling temperature, velocity and soot density fields with an accuracy of 88% in a second and detection time with 95% accuracy. The proposed GAN model enables a smart fire detection analysis, reduces the fire engineering design cost, and improves fire safety for complex buildings.

Protection Design and Effectiveness Verification of High-temperature Fire for Civil Aviation Emergency Locator Transmitter

Considering the coupling between the heat of emergency locator transmitter and the external high-temperature fire environment, a thermal protection system for external insulation and internal heat absorption is proposed. The external insulation layer consists of flexible nanofiber heat insulation film and quartz ceramics to withstand the thermal impact of the external environment. The internal heat absorption layer is composed of microcapsulated paraffin, which is used to absorb the heat transmitted through the insulation layer and the heat generated by emergency locator transmitter. Using the enthalpy method to establish a transient heat transfer mathematical model of thermal protection system, and the protection performance of the system in high-temperature fire is analyzed. The calculation results show that the system can withstand a high-temperature fire for at least 15 minutes, during which the temperature of emergency locator transmitter is controlled below 60℃. After the fire is over, under the coupling of the waste heat of the incoming system and the heat of emergency locator transmitter, the temperature of emergency locator transmitter continues to rise to a maximum of 107℃. Then, as the influence of the waste heat of the incoming system weakens, the temperature of emergency locator transmitter gradually decreases. Finally, the accuracy of the simulation model and the effectiveness of the thermal protection system are verified through destructive experiments.

Nonlinear stability and design of prestressed stayed columns in fire considering non-uniform temperature distribution

Prestressed stayed columns are vulnerable to fire due to material weakening. The fire behaviour of the stayed columns is investigated with non-uniform temperature distributions considered using steady state analysis within ABAQUS. This study aims to reveal the load-carrying capacity reduction of stayed columns in fire and propose a design method. Results show that ultimate loads decrease with temperature increasing, and the stayed columns approximate failure at the temperatures higher than 600°C. The failure deflected mode maintains similar to the dominant linear buckling mode for the uniform temperature distribution, and the sensitivity of ultimate loads to prestressing levels becomes less significant at higher temperatures. Moreover, compared to buckling and ultimate behaviour, initial post-buckling behaviour shows more significant sensitivity to temperature distributions. The non-uniform distribution can lead to asymmetric deflected mode due to stiffness re-distribution from the material weakening at elevated temperatures, and the post-buckling behaviour of the cases with rotational symmetric mode dominance is sensitive to prestressing levels. Finally, a fire design method is proposed based on the ultimate load reduction in fire.

The Synergy of Local Government and Academia in Addressing Peatland Fires in Siak Regency with a Technology-Based Approach

This study aims to explore the synergy between the local government and academia in mitigating peatland fires in Siak Regency. In the fields of social humanities, science, and technology, this study uses an exploratory qualitative method. The study reveals the important role of the local government in disaster mitigation through regional regulations, policies, and synergy between related departments. Through the regional regulation on forest fire prevention and handling, the local government has involved the Regional Disaster Management Agency (BPBD) and other supporting units in mitigation efforts. In addition, academics have also contributed by developing a technology-based peatland fire detection system. The main results of this study show that collaboration between the local government and academia is very significant in peatland fire mitigation efforts. The role of the local government through Governor's Decree No. 9 of 2020 and Regent's Decree No. 4 of 2022, as well as synergy between departments, encourages more effective steps in preventing and handling peatland fires. In addition, the contribution of academics to producing a technology-based peatland fire mitigation technology design opens up the potential for innovative and sustainable solutions. These findings have significant implications, as they highlight the importance of collaboration between the local government and academia in facing the challenges of peatland fire mitigation in Siak Regency. This synergy allows a better understanding of the problem, the development of more effective policies, and the application of advanced technology in preventing and handling peatland fires.

Full-scale fire resistance tests of lightweight steel framed floor systems

As cold-formed steel profiles are increasingly used for load-bearing structural systems, their fire design requires specific attention due to their thin-walled nature and high slenderness. In some specific applications such as in storage hall floor systems, these structures are used without sheathing or thermal protection on the fire-exposed side. Yet, there is a lack of data from fire resistance tests on full-scale load-bearing thin-walled steel structures, especially with directly exposed steel. This article describes two standard fire resistance tests on full-scale light gauge steel frame floors made of cold-formed steel lipped channel girders and joists topped by chipboard panels. The experimental program was designed to investigate the fire resistance of the unprotected girders. A specificity of this program was that the girders were subjected to a low load level to probe the ability to achieve without passive fire protection a 30-min fire resistance rating typical for storage hall structures in the Czech Republic. The absence of protection resulted in differences in thermal gradients and bracing compared to common fire tests, as well as a very low degree of utilization leading to an expected failure temperature higher than 800 °C. The results showed that the two floors remained stable during the 30 min with limited deflections, but failed the deflection rate criteria after 24 and 22 min, respectively. Comparison is provided with the calculation methods from the Eurocodes. The presented results provide new data on the response of full-scale, unprotected cold-formed steel floor systems subjected to fire, which can be used to calibrate numerical models and fire design methods outside of the range currently covered by the codes.

Structural response and design of stainless steel hollow section columns at elevated temperatures

AbstractThis paper investigates the flexural buckling behaviour and design of stainless steel circular, elliptical, square and rectangular hollow section (CHS, EHS, SHS and RHS) columns at elevated temperatures through numerical modelling. Shell finite element models are utilised to perform numerical parametric studies whereby benchmark structural performance data are generated. A large number of cold‐formed and hot‐rolled austenitic, duplex and ferritic stainless steel CHS, EHS, SHS and RHS columns at elevated temperatures are taken into account, considering various cross‐section and member slendernesses. Since the fire design provisions provided in the European fire design standard EN 1993‐1‐2 for stainless steel columns are largely based on those originally developed for carbon steel columns, they typically lead to rather inaccurate ultimate resistance predictions for stainless steel columns at elevated temperatures. To address this, in the present study, a new flexural buckling design method for stainless steel hollow section columns at elevated temperatures is put forward. The accuracy, safety and reliability of the proposed design method and the provisions in EN 1993‐1‐2 are assessed. It is observed that the proposed fire design method leads to more accurate, safe‐sided and reliable flexural buckling resistance predictions for stainless steel hollow section columns at elevated temperatures relative to the provisions in EN 1993‐1‐2.

Resistance and behaviour of carbon steel and stainless steel columns with axial and rotational end‐restraints in fire

AbstractDue to the presence of neighbouring structural elements, carbon steel and stainless steel columns are typically axially and/or rotationally restrained at their ends in fire. Despite the significant influence of the axial and rotational end‐restraints on the behaviour, the fire design rules for steel columns provided in the European structural steel fire design standard EN 1993‐1‐2 were originally developed considering the structural response of axially unrestrained steel columns with pin‐ended support conditions. Thus, EN 1993‐1‐2 may provide inaccurate ultimate resistance predictions for axially and/or rotationally restrained steel and stainless steel columns in fire. Considering this, this paper investigates the behaviour and design of carbon steel and stainless steel columns with axial and/or rotational end‐restraints at elevated temperatures. A number of carbon steel and stainless steel I‐section columns are considered, taking into account different axial and rotational end‐restraint stiffnesses, room temperature loading ratios, member and cross‐section slendernesses. A new design method for the fire design of axially and/or rotationally restrained steel and stainless steel columns is put forward. The accuracy of the proposed new design method is extensively verified against the results from nonlinear shell finite element modelling.

Fire‐Induced Collapse of Automated Rack‐Supported Warehouses

AbstractAutomated self‐supporting rack warehouses are becoming increasingly common in the international logistics sector. Their static and seismic design has been studied in the literature; however, the fire design still needs to be improved. Some Standards, such as the Eurocodes or Italian Fire Code, accept the collapse of rack warehouses during fires but require avoiding a progressive collapse or obtaining an implosive collapse regardless of any other active or passive fire protection systems. A hierarchy that guides the kinematics of collapse needs to be defined appropriately but without any Code going into further details. Moreover, the scientific literature focuses more on optimizing fire protection systems for racks, such as sprinklers, rather than preventing fire‐induced progressive collapse. Here, a case study is presented, which, using finite element modelling, provide a first robustness evaluation and highlights some possible aspects to be considered in the structural design to avoid a progressive collapse in the event of a fire. The analyses are performed using the LOCAFI method for localized fires and nonlinear dynamic finite element simulations.

Optimized fire design for steel industrial sheds

AbstractThis paper showcases some of the main contributions from the research project Switch2Steel, in which a web application is developed for the calculation and optimization of the cost of steel industrial sheds. Unprotected steel structures, compared to other construction materials, possess relatively low fire resistance. To enhance their fire performance, adequate fire protection is required. Simplified fire design, without considering the real influence of the main parameters on the development and propagation of natural fires, often leads to excessive amounts of costly protective material. On the other hand, the use of advanced software tools may be impractical because of iterative time‐consuming computational processes such as structural optimization. Hence, this work presents a simple user‐friendly calculation tool that allows users to define the characteristics of the sheds to be built and based on a set of metrics, weights, and advanced algorithms, to minimize their cost by reducing the consumption of steel and fire protection material. To illustrate the use of the tool, a reference case of a steel industrial shed is selected and the results obtained by the tool are compared with those obtained by FEM tools. The tool gives more optimized results than the use of prescriptive rules, and the results are obtained considerably faster than by advanced expensive computational tools.