scholarly journals Performance-Based Analysis of Single-Layer Cylindrical Steel Reticulated Shells in Fire

2020 ◽  
Vol 10 (9) ◽  
pp. 3099
Author(s):  
Zhiwei Yu ◽  
Chen Lu ◽  
Yiqin Zhong
Keyword(s):  
Fire Resistance ◽  
Rapid Development ◽  
Single Layer ◽  
Steel Structures ◽  
Temperature Fields ◽  
Fe Model ◽  
Fire Dynamics ◽  
Interior Space ◽  
Coating Materials ◽  
Fire Scenarios

With the rapid development of architectural technology, long-span structures have been widely used due to their vast interior space and beautiful architectural composition. Due to the characteristics and high costs of coating materials on large steel structures, fire resistance designs for these kinds of structures have become more and more important. This paper presents comprehensive case analyses of the fire performance of single-layer cylindrical reticulated shells. Nonuniform fire temperature fields of single-layer cylindrical reticulated shells in different fire scenarios were generated using a Fire Dynamics Simulator (FDS). The influences of different parameters on the air temperature field during a fire in a reticulated shell structure were analyzed. A Finite Element (FE) model was developed using the FE software ABAQUS to model the structural behavior of single-layer cylindrical reticulated shells in different fire scenarios. The effects of various parameters on the responses of single-layer cylindrical reticulated shells during a fire were investigated. Using the results from the performance-based analysis in this research, we propose some recommendations for fire resistance designs for single-layer cylindrical reticulated shells.

A scenario-based methodology for determining fire resistance ratings of irregular steel structures

2019 ◽  
Vol 23 (1) ◽  
pp. 89-103
Author(s):  
Behrouz Behnam
Keyword(s):  
Fire Resistance ◽  
Safety Margin ◽  
Steel Structures ◽  
Soft Story ◽  
Regular Structures ◽  
Natural Fires ◽  
Irregular Structures ◽  
Fire Scenarios ◽  
Fire Resistance Rating ◽  
Resistance Rating

This article investigates the response of irregular steel structures under natural fires. As the severity and duration of natural fires depend on many factors, a probabilistic-based approach known as two-level factorial design is used, whereby possible fire scenarios are considered based on the minimum and maximum values of the involved factors. Two seven-story regular steel structures with three span lengths of 5500 and 7000 mm are designed to meet a 2.0-hr fire resistance rating based on the ISO834 fire. Two types of irregularities, setback and soft story, are then imposed on the regular structures to make them irregular. The regular and irregular structures are then exposed to the fire scenarios (32 in total) to evaluate their fire resistance ratings. The results show that while the regular structures are able to meet the required fire resistance rating under all of the fire scenarios, this is not the case for the irregular structures. It is shown that the reduction in the fire resistance ratings of the setback and the soft-story structures can be as low as 45% and 33% that of the required fire resistance ratings, respectively. Also, the setback irregular structures tend to collapse laterally, hence endangering the safety of adjacent buildings. To address the above deficiencies, it is proposed here that the maximum surface temperature on the structural members should be limited to 415°C–460°C. Alternatively, providing a 20%–25% increase in the insulation thickness can provide the required safety margin as dictated by fire codes.

scholarly journals Fire Protective Glass Fiber Reinforced Concrete Plates for Steel Structures under Different Types of Fire Exposure

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 187
Author(s):  
Marina Gravit ◽  
Elena Golub ◽  
Boris Klementev ◽  
Ivan Dmitriev
Keyword(s):  
Fire Resistance ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Lightweight Concrete ◽  
Limit State ◽  
Single Layer ◽  
Steel Structures ◽  
Fiber Reinforced Concrete ◽  
Fire Tests ◽  
Standard Fire

In a situation where a fire occurs either in a tunnel with a burning vehicle carrying petroleum products, at an offshore platform, or at an oil and gas asset to be protected, such a case is commonly described using a hydrocarbon fire curve. Therefore, it is extremely important to design construction, which can maintain stability and bearing capacity both under the standard and hydrocarbon fire modes. The purpose in this work is to hold a behavior simulation of a steel structure with fireproofing ensured through lightweight concrete slabs reinforced with fiber glass as well as a validation of the outcomes by assessing the experimental findings obtained from the relevant fire tests. A fire resistance study was carried out here for steel structures with a profile ratio of 156 mm−1 for the cases of a standard fire and of a hydrocarbon fire. A constant static load of 687 kN (70 tf) was taken for standard fire and 294 kN (30 tf) for hydrocarbon fire; the column was under vertical compression with one end resting on a hinged support and the other end rigidly fixed. The specimen design incorporated single-layer box-section cladding made of Pyro-Safe Aestuver T slabs, 40 mm thick and of a 650 kg/m3 density, pre-cut to fit the column size. The column strength loss (R) ultimately occurred after 240 min in the standard fire case and after 180 min in the hydrocarbon fire case. As the breach in the fireproofing structural integrity (E) or the installation accuracy cannot be considered, the limit state indicators may show certain discrepancies. According to the simulation performed using SOFiSTiK software, the design fire resistance rating of the structure in a hydrocarbon fire case was 58% higher than the figure obtained by holding fire tests due to the slabs cracking during the experiment session; the discrepancy between the outcomes of the session and the simulation in a standard fire case was as much as 15%.

scholarly journals An Intelligent Task Scheduling Mechanism for Autonomous Vehicles via Deep Learning

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1788
Author(s):  
Gomatheeshwari Balasekaran ◽  
Selvakumar Jayakumar ◽  
Rocío Pérez de Prado
Keyword(s):  
Execution Time ◽  
Autonomous Vehicles ◽  
Rapid Development ◽  
Single Layer ◽  
Battery Life ◽  
Learning Approaches ◽  
Task Management ◽  
Inference System ◽  
Safe Driving ◽  
Self Driving Cars

With the rapid development of the Internet of Things (IoT) and artificial intelligence, autonomous vehicles have received much attention in recent years. Safe driving is one of the essential concerns of self-driving cars. The main problem in providing better safe driving requires an efficient inference system for real-time task management and autonomous control. Due to limited battery life and computing power, reducing execution time and resource consumption can be a daunting process. This paper addressed these challenges and developed an intelligent task management system for IoT-based autonomous vehicles. For each task processing, a supervised resource predictor is invoked for optimal hardware cluster selection. Tasks are executed based on the earliest hyper period first (EHF) scheduler to achieve optimal task error rate and schedule length performance. The single-layer feedforward neural network (SLFN) and lightweight learning approaches are designed to distribute each task to the appropriate processor based on their emergency and CPU utilization. We developed this intelligent task management module in python and experimentally tested it on multicore SoCs (Odroid Xu4 and NVIDIA Jetson embedded platforms).Connected Autonomous Vehicles (CAV) and Internet of Medical Things (IoMT) benchmarks are used for training and testing purposes. The proposed modules are validated by observing the task miss rate, resource utilization, and energy consumption metrics compared with state-of-art heuristics. SLFN-EHF task scheduler achieved better results in an average of 98% accuracy, and in an average of 20–27% reduced in execution time and 32–45% in task miss rate metric than conventional methods.

scholarly journals Finite Element Study of Container Structure under Normal and High Temperature

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaoxiong Zha ◽  
Yang Zuo
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Research Result ◽  
Temperature Curve ◽  
Temperature Fields ◽  
Wind Loading ◽  
Coupled Analysis ◽  
Fire Dynamics ◽  
Standard Temperature ◽  
Actual Temperature

This paper does some research on the mechanical property of multilayer container structure under high temperature and gives some suggestions on how to make fire protection based on the performance-based fire design. Firstly, using the software of FDS (Fire Dynamics Simulator), the fire background and fire heating release curve are determined. Through the simulation, the actual temperature curves (of the top and bottom temperature curves of the middle, door, and corner position in the container) are obtained and compared with the standard temperature curve of ISO-834. Secondly, using the software of Abaqus, a full scale finite element model of multilayer container structure is established. Two temperature fields under the standard temperature curve of ISO-834 and the actual temperature curve (of the most unfavorable curve of the top temperature curve of the middle position in the container) are obtained, respectively. Thirdly, the thermal-mechanical coupled analysis is carried out for the container structure under the wind loading and temperature field. The research result can be feasible in design and construction of container buildings and provides some references to corresponding specification preparation.

Structure-Soil Interaction of Buried Corrugated Steel Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2112-2117
Author(s):  
Miao Xin Zhang ◽  
Bao Dong Liu ◽  
Peng Fei Li ◽  
Zhi Mao Feng
Keyword(s):  
Finite Element ◽  
Steel Structures ◽  
Internal Force ◽  
Structural Deformation ◽  
Fe Model ◽  
Soil Pressure ◽  
Load Range ◽  
Finite Element Program ◽  
Load Conditions ◽  
Peak Value

Corrugated steel plate and surrounding soils are working together to share the load in buried corrugated steel structures. It is complicated to consider the structure-soil interaction, so the finite element method has already become the chief means of complicated structure analysis. Based on a practical project, considering structure-soil interaction, by using the finite element program of ANSYS, the paper set up a 2-D FE model and analyzed the soil pressure, the structural deformation and the internal force under different load conditions in detail. The analysis shows that structure-soil interaction has brought about stresses redistribution of surrounding soils, and adverse effects of soil pressure and displacement were limited. The variation range of soil pressure on the crown of arch increases with the load increases and the peak value of soil pressure approach to the code value and a rebound appears in the vehicle load range. The tendencies of vertical soil displacement are nearly the same to different load conditions, and the peak value of moments has an obvious change and can be influenced greatly by deflective load.

Fire of steel and composite beam bridges

2019 ◽  
Author(s):  
Henryk Zobel ◽  
Wojciech Karwowski ◽  
Agnieszka Golubińska ◽  
Thakaa Al-Khafaji
Keyword(s):  
Fire Resistance ◽  
Composite Beam ◽  
Structural Integrity ◽  
Bridge Structure ◽  
Long Span ◽  
Long Span Bridge ◽  
Bridge Structures ◽  
Fire Scenarios ◽  
Design Construction ◽  
Cable Stayed Bridges

<p>The problem of bridge fires is growing. Because of a bad experience in Poland, it was decided to improve fire resistance of long span bridge structures, and of cable-stayed bridges in particular. Statistics shows that fire is a real threat to this kind of structure. They also confirm that the worst results of fire are for those with an orthotropic deck rather than with a concrete one. The basic problems to solve are how to predict fire resistance of a particular bridge and how to ensure safety and structural integrity of the bridge structure. Taking into account the fact that bridge standards do not include information relating to fire protection, and fire standards do not determine rules for design, construction and maintenance of such structures, there are no regulations for this problem. Fire scenarios are devoted to buildings, but the thermo-structural behavior of bridges is different.</p>

Simulation and Modelling in Fire Safety

2020 ◽  
pp. 232-262
Author(s):  
Tomaz Hozjan ◽  
Kamila Kempna ◽  
Jan Smolka
Keyword(s):  
Virtual Reality ◽  
Fire Safety ◽  
Rapid Development ◽  
Fire Spread ◽  
Practical Training ◽  
Smoke Movement ◽  
Fire Engineering ◽  
Limited Budget ◽  
Fire Scenarios ◽  
In Fire

Actual and future concerns in fire safety in buildings and infrastructure are challenging. Modern technologies provide rapid development in area of fire safety, especially in education, training, and fire-engineering. Modelling as a tool in fire-engineering provides possibility to design specific fire scenarios and investigate fire spread, smoke movement or evacuation of occupants from buildings. Development of emerging technologies and software provides higher possibility to apply these models with interactions of augmented and virtual reality. Augmented reality and virtual reality expand effectivity of training and preparedness of first (fire wardens) and second (firefighters) responders. Limitations such as financial demands, scale and scenarios of practical training of first and second responders are much lower than in virtual reality. These technologies provide great opportunities in preparedness to crisis in a safety way with significantly limited budget. Some of these systems are already developed and applied in safety and security area e.g. XVR (firefighting, medical service).

Определение требуемой толщины вспучивающегося огнезащитного покрытия на стальных конструкциях для заданных пределов огнестойкости

2020 ◽  
Author(s):  
Yury Shebeko ◽  
Aleksey Shebeko ◽  
Andrey Zuban
Keyword(s):  
Fire Resistance ◽  
Confidence Level ◽  
Fire Retardant ◽  
Steel Structure ◽  
Steel Structures ◽  
Mean Square ◽  
Mean Square Deviation ◽  
R Value ◽  
The Given

Проанализирована взаимосвязь разброса значений пределов огнестойкости стальных конструкций со вспучивающимися огнезащитными покрытиями и соответствующего этому разбросу интервала толщины огнезащитного покрытия. Предложена методика, на основании которой может быть осуществлен выбор необходимой толщины огнезащитного покрытия в зависимости от заданных значений дисперсии предела огнестойкости и приведенной толщины конструкции при заданной доверительной вероятности.An analysis of a relationship between fire resistance limits scatter for steel structures coated with intumescent fire retardant coating and an appropriate interval of thicknesses of the coating was carried out. A methodology for the determination of this relationship was proposed. This methodology was tested on a practical example. A steel structure with a reduced thickness of 6 mm was considered. A typical dependence of the required thickness of the structure was taken into account. A ratio of a mean square deviation of the fire resistance limit to this limit was accepted to be equal 0.1. Using these values an appropriated interval of the thicknesses of the intumescent fire retardant coating was determined. This interval can be calculated for any given confidence level. Boundaries of this interval can be not symmetric in relation to the value of the normative thickness of the fire retardant coating. The proposed methodology can be used for the determination of the required thicknesses of the intumescent fire retardant coatings on steel structures for the given r value, reduced thickness of the structure and the confidence level.

scholarly journals PERFORMANCE BASED DESIGN OF UNBRACED STEEL FRAMES EXPOSED TO NATURAL FIRE SCENARIOS

2016 ◽  
Author(s):  
Carlos Couto ◽  
Thiago Silva ◽  
Martina Carić ◽  
Paulo Vila Real ◽  
Davor Skejić
Keyword(s):  
Fire Resistance ◽  
Steel Frames ◽  
Design Methods ◽  
The Other ◽  
Performance Based Design ◽  
The Finite Element Method ◽  
Natural Fire ◽  
Fire Scenarios ◽  
Buckling Coefficient ◽  
Structural Engineers

<p>According to the Eurocode 3 Part 1-2 (EN1993-1-2) (CEN 2005b), it is possible for structural engineers to consider physical based thermal actions and to do performance based design instead of using prescriptive rules based on nominal fire curves. However, some uncertainties remain in the use of such approaches. This study focus on the clarification of the use of the simplified design methods to assess the fire resistance of unbraced steel frames exposed to fire. On the other hand, a recent study (Couto et al. 2013) suggests the use of a buckling coefficient of 1.0 for all the columns except those belonging to the first storey of a pinned framed where 2.0 should be taken instead and it is unclear if the consideration of such values for the buckling lengths is adequate when using performance based designs.</p>In this study, a comparison is made between simple and advanced calculation models and it is demonstrated that the simple design methods, using the suggested buckling coefficients to calculate the fire resistance of the frames are safe sided when compared to the use of advanced calculations using the finite element method (FEM).

scholarly journals Numerical Study of Alternative Seismic-Resisting Systems for CLT Buildings

Buildings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 162 ◽  
Author(s):  
Cristiano Loss ◽  
Stefano Pacchioli ◽  
Andrea Polastri ◽  
Daniele Casagrande ◽  
Luca Pozza ◽  
...  
Keyword(s):  
Numerical Study ◽  
High Capacity ◽  
Shear Walls ◽  
Sustainable Urban Development ◽  
Fe Model ◽  
Base Shear ◽  
Interior Space ◽  
Linear Dynamic ◽  
Story Drift ◽  
Uplift Forces

Changes to building codes that enable use of materials such as cross-laminated timber (CLT) in mid- and high-rise construction are facilitating sustainable urban development in various parts of the world. Keys to this are the transition to multi-performance-based design approaches along with fewer limitations on heights or the number of storeys in superstructures constructed from combustible materials. Architects and engineers have increased freedom to apply new design and construction concepts and methods, as well as to combine timber with other structural materials. They also have started to develop wall arrangements that optimise interior space layouts and take advantage of the unique characteristics of CLT. This paper discusses the seismic response of multi-story buildings braced with a CLT core and perimeter shear walls anchored to foundations and floor platforms using modern high-capacity angle brackets and hold-downs, or X-Rad connectors. Linear dynamic finite element (FE) models of seismic responses of superstructures of various heights are presented, based on experimentally determined characteristics of wall anchor connections. Particular attention is given to fundamental vibration periods, base shear and uplift forces on walls, as well as inter-story drift. Discussion of FE model results focuses on structural engineering implications and advantages of using CLT to create shear walls, with emphasis on how choice of wall anchoring connections impacts the possible number of storeys and configurations of superstructures. Employing CLT shear walls with X-Rad or other types of high capacity anchoring connections makes possible the creation of building superstructures having eight and potentially more storeys even in high seismicity regions. However, it is important to emphasise that proper selection of suitable arrangements of shear walls for CLT buildings depends on accurate representation of the semi-rigid behaviors of anchoring connections. The linear dynamic analyses presented here demonstrates the need during engineering seismic design practices to avoid use of FE or other design models which do not explicitly incorporate connection flexibilities while estimating parameters like fundamental periods, base shear and uplift forces, as well as inter-story drift.

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