Capacity reduction and fire load factors for LRFD of steel columns exposed to fire

Capacity reduction and fire load factors corresponding to the load and resistance factor design (LRFD) format are developed for steel columns exposed to fire. A sample deterministic framework to determine fire and steel temperatures and the capacity of steel columns is adopted for this analysis to structure the methodology. A specific number of parameters that affect the structural response, including the fire load, ratio of floor area to the total area of the fire compartment, opening factor, thermal absorptivity of compartment boundaries, thickness, density and thermal conductivity of insulation, dead load, and live load are taken as random variables. Mechanical and sectional properties of steel (e.g., yield strength, cross-sectional area, etc.), are also considered to be random variables. The effect of active fire protection systems (e.g., sprinklers, smoke and heat detectors, fire brigade, etc.), in reducing the probability of occurrence of a severe fire is included. Given the choice of framework and based on detailed reliability analyses, it is shown that the capacity reduction and fire load factors should vary depending on the presence of active fire protection systems in a building.     

Life cycle structural integrity management of offshore structures

An overview of structural integrity management of offshore structures in the oil and gas energy sector is presented in this article. Based on relevant experiences with the hazards, accidents and means to control the associated risks are categorised from a technical and physical as well as human and organisational point of view. Structural risk relates to extreme environmental and accidental events, as well as structural degradation and can be controlled by use of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. Such measures are briefly outlined, with an emphasis placed upon a quantitative design approach for dealing with a life cycle approach especially relating to crack degradation phenomena. The current status of risk and reliability methodologies to aid decisions in the safety management of novel and mature offshore structures is briefly reviewed.     

Das Sandwich‐Platten‐System (SPS)

Sandwich Plate System (SPS). SPS was initially developed to provide impact resistant plating for offshore structures, ice islands, working in the Canadian Beaufort Sea. Research and development over the last thirteen years has focused on basic research into structural behaviour and performance, material characterization, fire resistance and fire engineering analyses, as well as development of design rules and energy absorption design philosophies. In addition connection details specific to sandwich plate structures and methods for in‐situ installations (SPS Overlay), repair, prefabrication and inspection have been developed. This work summarized in this paper, clearly demonstrates that not only SPS plates can be designed to be structurally equivalent to stiffened steel plates, but that the implied economical use of SPS plates provides a number of further advantages with respect to performance and safety.     

复杂空间钢结构整体性防火分析的系统方法研究

复杂空间钢结构建筑的飞速发展为结构防火分析和设计带来了新的挑战。在分析现有规范和性能化设计方法中结构防火设计不足的基础上,基于火灾科学、结构工程、计算机模拟等多个学科领域的知识和研究成果,立足于复杂空间建筑的整体防火性能模拟与分析的理论研究和实际应用,建立空间整体结构火灾-结构耦合分析模型和系统集成方法,提出复杂空间结构整体性防火分析的系统分析模型,并进行实例研究。该系统分析模型综合考虑实际火灾的发展蔓延过程以及火灾对结构体系的影响,研究建筑火灾中火场状况与空间结构体系之间的相互关系,对大空间建筑在各种火灾场景下的结构反应进行仿真模拟,从而进行整体性系统化的分析和评估。本课题的研究在理论分析的基础上为结构整体防火分析提出了新的手段和思路,可为我国建筑防火研究和建筑防火设计、消防救援、应急预案制定等工程实际应用提供有益的参考。     

城市燃气消防工作中“消”的重要性

结合实际案例,论述了城市燃气消防工作中“消”的重要性,分析了城市燃气火灾爆炸事故的原因、特点、灭火防爆原理,提出了灭火防爆方法和对城市燃气安全管理的建议。     

石油罐区火灾爆炸事故风险评价

为研究石油罐区火灾爆炸事故多因素耦合视角下的风险定量评价方法,从人、机、环、管四个方面进行石油罐区火灾爆炸事故风险因素辨识,基于系统动力学构建石油罐区火灾爆炸事故风险因素因果回路模型研究各风险因素之间的耦合作用;通过构建相互作用矩阵对石油罐区进行风险评价研究,得出耦合视角下石油罐区火灾爆炸事故风险权重及风险评价等级;结合惠州某石油罐区实际案例对该风险评价模型进行应用。结果表明,该石油罐区风险处于中度风险严重度状态,影响该石油罐区安全最主要的因素包括人员违章操作风险、设备故障风险、安全管理实施力度风险以及人员安全意识风险。     

基于足尺抗火试验的三维框架结构消防安全分析

分析三维框架结构(如工业厂房)的消防安全。冷弯薄钢板作为结构构件使用,并对建筑进行了足尺抗火试验。利用有限元模型SAFIR进行盲预测分析,对火灾荷载密度为625MJ/m2、通风系数为0.009m1/2的标准火灾和自然火灾下结构构件的热响应进行预测。与预期一样,由于是薄钢板,冷弯截面的温度或多或少与防火分区内气体温度相关。力学响应的预测结果给出了27min(标准火灾)和54min(自然火灾)的抗火能力。利用足尺抗火试验结果对模型进行了验证,证明了62min的抗火能力。与一个简单的2.5D模型进行比较,证明了所提供的结果足够精确、适用于日常设计。     

An integrated approach for fire and explosion consequence modelling

Fire and explosion are accidents which potentially can occur in oil and gas processing facilities. While fire and explosion could occur as a consequence of each other, most published work has assessed fire and explosion separately, ignoring interactions between the two phenomena.The current study proposes a novel approach to model the entire sequences involved in a potential accident using liquid and gas release incidents as two test cases. The integrated scenario is modelled using Computational Fluid Dynamics (CFD) codes FLACS and FDS. An integrated approach is adopted to analyse and represent the effects (injuries/death) of the accident. The proposed approach can be used in designing safety measures to minimize the adverse impacts of such accidents. It can also serve as an important tool to develop safety training to improve emergency preparedness plans.     

建筑外墙外保温材料防火安全的选型设计探讨

近年来,我国因建筑外墙外保温材料防火安全问题而导致特大火灾事故频发,尤其是上海胶州路教师公寓火灾、沈阳皇朝万鑫大厦火灾和北京央视大楼火灾,造成重大人员伤亡和财产损失,使得建筑外墙外保温材料防火安全成为人们关注的焦点。该文针对目前建筑外墙外保温材料选型设计中不注重防火安全的实际问题,分析了各种建筑外墙外保温材料防火性能,探讨其不同的使用局限性和优缺点,为建筑外墙外保温材料的选型设计提供参考。     

Nonlinear analysis of reinforced concrete cross-sections exposed to fire

A nonlinear structural analysis of cross-sections of three-dimensional reinforced concrete frames exposed to fire is presented. The analysis includes two steps: the first step is the calculation of the transient temperature field in cross-sections exposed to fire and the second step is the determination of the mechanical response due to the effect of thermal and mechanical load. A nonlinear finite-element procedure is proposed to predict the temperature field history. In this thermal analysis, the effect of moisture has been taken into account by introducing a water vapor fraction function to define the variation of enthalpy. A mechanical nonlinear analysis of the cross-sections is performed for each temperature distribution and for the applied exterior load using an algorithm of arc-length control. The mechanical and thermal properties of concrete and steel are taken according to the European Standard ENV 1991-1-2 [ENV. Eurocode 2, design of concrete structures, part 1–2: general rules—structural fire design. ENV 1992-1-2, 1995]. In order to validate the proposed thermal and mechanical models, comparisons between numerical and experimental results have been performed. The agreement found is in both cases, fairly good. In addition, a numerical example of the structural analysis of several cross-sections of a reinforced concrete waffle slab under external load and fire is shown.     

现役结构安全度评估的环境荷载标准研究

本文在承认结构设计环境荷载基准期的确定是合理的基础上，通过引进结构设计使用期和结构评估再服役期，提出了以评估再服役期超越评估荷载的概率应等于设计使用期超越设计荷载的概率为原则（类比地）确定评估荷载基准期的方法２对于直接采用确定性或随机的环境荷载进行结构安全程度或可靠度评估的情况，分别导出了相应的评估荷载与设计荷载的关系；最后对建筑结构评估用风荷载和地震荷载的确定以及渤海８号平白评估用海洋环境荷载进行了具体的讨论，并得出了相应的结果。     

某煤化工企业煤气化装置火灾爆炸事故模拟

以某大型煤化工企业为例，运用SAFETI软件对煤气化装置火灾爆炸事故后果进行模拟分析，设置多个模拟场景，评估事故的影响范围及危害性，为企业安全防范设计及管理措施提供依据。通过实例分析，煤气化装置生产工艺设备繁杂，生产介质种类多，火灾危险性大，在进行事故后果模拟分析时，设置多个事故模拟场景是十分必要的。     

液体危化品远程无人化侦检装备研发

针对液体危化品泄漏导致的火灾爆炸事故中快速初步无人化侦检需求,利用手持激光拉曼光谱仪OEM内芯,采集了我国37种重点监管液体危化品的拉曼谱图,经过数据处理,建立了包含我国重点监管液体危化品的拉曼光谱数据库,并在此之上自主研发了消防机器人挂载的滚动式液体危化品侦检球,通过机械臂抛投至石化爆燃等现场,可实现泄漏液体危化品的无人化自动采样、识别及数据回传,为液体危化品泄漏火灾或燃爆事故态势的感知研判提供技术和装备支撑,同时保证了消防员的人身安全。     

气雾剂火灾危险性分级方法研究

综述国内外气雾剂产品安全的相关研究,介绍气雾剂的火灾危险性及我国发生气雾剂火灾爆炸事故的情况。研究联合国橙皮书关于危险货物运输的建议书中关于气雾剂火灾危险性分级的试验内容,以及泡沫气雾剂、喷雾气雾剂的火灾危险性分级方法。在对此类方法研究的基础上,结合实际情况建立适宜我国经济发展和安全保障的气雾剂的火灾危险性分级方法,可以为相关行业标准的出台作技术性铺垫。     

Determination of the steel fire protection material thickness by an analytical process—a simple derivation

Structural fire safety is assured if the design value of the effect of the actions (thermal and mechanical) is lower than the design value of each structural element fire resistance or, in other words, structural safety is assured when the steel temperature in a fire situation only reaches values less than the structure critical temperature. The critical temperature is the temperature that causes structural collapse in a fire situation. The temperature in the structural element can be determined either experimentally or analytically. In the case of a structure covered with thermally protective material, such methods serve, in practice, to determine the thickness of the protective material. In this work, a previously unpublished expression for the calculation of the temperature in thermally protected steel structural elements in fire is derived. Comparisons with international recommendations and with experimental and numerical analysis results are made. In view of its simple form and derivation, the use of such expression is recommended for the revision of the Brazilian Standard “Steel structures fire design”.     

A method for progressive structural crashworthiness analysis under collisions and grounding

Collisions and grounding always give rise to structural crashworthiness issues involving crushing, yielding, and fracture. For accidental limit state design and safety assessment associated with collisions and grounding, the resulting progressive structural crashworthiness characteristics should be analyzed to evaluate the energy absorption capability of the structure in the corresponding accidental event in conjunction with the associated criteria. The accidental energy absorption capability of a structure under collisions or grounding can be predicted by integrating the area below the reaction forces versus penetration curve until or after the accidental limit state is reached. For risk assessment associated with such accidents, the results of structural crashworthiness analysis are also used as a basis of the consequence analysis. The aim of the present paper is to present an efficient and accurate method which is useful for the progressive structural crashworthiness analysis of ships and ship-shaped offshore structures under collisions or grounding. Theoretical outline of the method is addressed. Application examples of the method to ship-shaped test structures are presented by a comparison with experimental results.     

液化石油气储罐火灾爆炸模拟评价方法研究

系统分析了液化石油气的危险特性 ,结合典型事故案例 ,对液化石油气火灾爆炸事故发生的过程、机理进行了研究与分析。     

某鼓楼式高层酒店结构抗火与防火设计分析

以某鼓楼式高层建筑为例,针对其造型独特、外观新颖和民族特色鲜明的特点,以结构抗火和防火设计中存在的难点为切入点,在确保该建筑的结构抗火和建筑防火安全的前提下,依据国家有关规范、标准,基于结构可靠度和智慧防火理念,对其结构抗火材料、安全疏散、消防登高操作场地及消防设施设计的优化措施进行探讨。提出在设计类似鼓楼式的高层建筑时,应充分考虑火灾与风荷载等多灾种的耦合性,积极应用智慧消防等新技术,全面提升其结构可靠度和消防安全性。