高温下钢管自密实混凝土柱抗火性能试验研究

进行了圆钢管自密实混凝土柱的高温抗火性能试验研究,主要测量钢管表面的温度场、构件轴向变形和跨中侧向位移随时间的变化关系;分析了各种因素对耐火极限和轴向变形、跨中侧向位移曲线的影响规律。     

钢结构防火保护新技术

随着大型钢结构建筑的日益增多,钢结构的防火保护越来越受到人们的关注.硬硅钙板包敷钢构件的防火保护方法具有强度高、隔热性能好、施工方便、无环境污染、耐久等优点,是一种理想的钢结构耐火保护方式.本文介绍了硬硅钙板的生产工艺、技术性能及施工方法,探讨了这种防护方法的特点及推广前景.     

The reinstatement of fire damaged steel framed structures

The paper examines the factors which can cause steelwork to distort and collapse during fires. In many situations no distortion occurs and the steelwork may be reused.Laboratory based experiments are described in which the strengths of various grades of steel were determined at elevated temperatures. The effects on mechanical properties of heating steelwork to temperatures in the range 100 — 1000°C and cooling back to ambient temperature have also been assessed. It has been shown that mild and microalloyed steels are likely to show distortion or collapse if they are heated to temperatures above 600°C, but no deterioration in mechanical properties occurs on cooling back to room temperature until steel temperatures have exceeded 650 °C.The available data on cast and wrought iron in fires are also summarised; these materials show similar behaviour to that of steels.Metallurgical examinations of several samples retrieved from the frameworks of structures involved in fires are included.Some guidelines are presented describing the major factors to be considered when contemplating the reinstatement of a steel framework after a fire. However, decisions on reinstatement need to be taken in the light of expert engineering and metallurgical advice in each individual case. This paper is intended for guidance purposes only and is not intended to be used as a definitive reference for such decisions.     

Temperature analysis of heavily-insulated steel structures exposed to fire

An exact analytical one-dimensional solution of the temperature response of insulated steel structures is derived and a closed form solution is given for a structure exposed to the ISO 834 standard curve.

Alternative approximate solutions are also given where all the heat capacity is assumed lumped in the steel core; only one third of the insulation heat capacity is then considered. It is also shown that approximate solution schemes given elsewhere strongly underestimate the temperature rise in structures protected with heavy insulations system. In addition the theoretical background of a proposed NORDTEST test method on how to obtain the thermal properties of an insulation system is outlined. Finally a numerical calculation scheme is recommeded.     

钢结构防火涂料的应用分析

随着钢结构防火涂料的使用日益广泛,国内外对其的研究也越来越多。本文对钢结构涂料的应用及今后的发展方向做了简单分析。首先介绍了防火涂料的工作原理和分类;接着对防火涂料的应用现状进行了分析,提出了存在的问题和解决方案;最后明确了钢结构防火涂料的发展方向。     

Survivability of steel frame structures subject to blast and fire

The lesson learned from the terrorist attacks on buildings is the need to assure structures’ ability to sustain local damage without total collapse. Some of the terrorist attacks take the form of blast followed by fire which may cause catastrophic failure of the structure. This paper presents a numerical model for analyzing steel frame structures subject to localized damage caused by blast load and subsequently investigating their survivability under fire attack. The proposed numerical method adopts a mixed-element approach for modeling large-scale framework and it is proven to be sufficiently accurate for capturing the detailed behaviour of member and frame instability associated with the effects of high-strain rate and fire temperature. Design implications related to the use of various numerical models for separate assessment of blast and fire resistance of steel structures and their components are discussed. Fire–blast interaction diagrams are generated to determine the fire resistance of columns considering the initial damage caused by the blast loads. A multi-storey steel building frame is analyzed so that the complex interaction effects of blast and fire can be understood and quantified. The frame is found to be vulnerable, as it possesses little fire resistance due to the deformation of key structural elements caused by the high blast load.     

钢结构防火涂料喷涂方面的问题

为了提高钢结构防火涂料的喷涂质量 ,确保钢结构的耐火极限 ,辽宁省消防技术检测站依据国家有关规范、规定 ,制定了《钢结构防火涂料检验规程》,购置仪器设备 ,并于 2 0 0 0年 12月起对钢结构防火涂料的喷涂质量进行了检验 ,经对沈阳市 2 7个单位的统计 ,合格率仅占 70 % ,这充分说明了问题的严重性 ,同时也证明了对钢结构防火涂料喷涂质量进行检验的重要性和必要性。现借贵刊将这些问题赘述于后 ,期望能引起各有关方面的注意 ,切实从方方面面提高钢结构防火涂料的喷涂质量 ,确保钢结构的耐火极限 ,减少火灾损失 ,更好地保护国家和人民生命…     

Determination of accidental forklift truck impact forces on drive-in steel rack structures

The paper addresses the problem of determining the accidental forklift truck impact forces on steel storage racks. Based on first principles of mechanics, simple models of a loaded forklift truck and a drive-in racking structure are presented. Model masses, as well as stiffness and damping coefficients are calibrated against experimental results obtained from tests of a forklift truck and a drive-in racking structure. Comparisons between experimental results and solutions obtained from the simple mechanical models show that the simple models accurately reproduce the static and dynamic behaviours of their associated structures. Based on the drive-in rack impact test results presented in a companion paper (Gilbert and Rasmussen, submitted for publication) [1] and the simple mechanical models for drive-in racks, actual impact forces are calculated and presented. Finally, using the impact test results and the simple mechanical models, the actual motion of the forklift truck body is calculated. This motion, being a common characteristic to all drive-in racking impacts, allows impact forces to be obtained for various pallet loads, impact elevations and rack characteristics. Thus, the paper concludes with a general method for calculating forces generated under forklift truck impact.     

Optimising design decision-making for steel structures in fire using a hybrid analysis technique

Steel structures can be protected against the effects of fully-developed fires by the use of sprayed on materials, board systems and intumescent paints, etc. or by using sufficiently large unprotected elements. This paper presents how optimum decisions for the protection of steel structures in fires can be achieved in a performance-based design environment, given conflicting structural fire design decision criteria and multidisciplinary fire design stakeholder views. In particular, a novel hybrid analysis approach is proposed for combining stakeholder views on the different fire protection options and the numerical outcomes of structural fire analysis. As for the stakeholder views, reference is made to benefits and costs criteria priorities for assessing competing options resulting from a previous study from the same authors. The fire protection structural performance is numerically and probabilistically assessed according to a parametric study. The proposed approach is exemplified by making reference to a limit state structural fire design of single steel elements. A synthesis and ranking technique is then applied to integrate the qualitative results obtained in terms of benefits and costs priority scores; and the quantitative measures of failure probabilities and costs for the different fire protection options. The results show that the ranking technique accounts for multidimensionality in synthesising the structural fire design decision problem. The results also show that intumescent paints and board systems are the most cost-effective options in different stakeholder influence scenarios, given a general selection of steel structural fire protection. The hybrid technique is proposed to support an optimal and cost-effective structural fire design decision-making for buildings in a performance-based design environment.     

Nonlinear behavior of steel structures considering the cooling phase of a fire

The nonlinear behavior of steel structures considering the heating and the cooling phases of a fire is investigated by the Vector Form Intrinsic Finite Element (VFIFE) method. The temperature dependent constitutive relations of steel which include strain reversal effects are adopted. The numerical model is first verified by comparing the results with the published analytical and experimental results for steel structures in the cooling phase. Several numerical examples are then fully studied to investigate the cooling behavior of steel structures. The proposed numerical model can effectively predict the nonlinear behavior of the steel structure in both the heating and cooling phases.     

型钢混凝土框架结构耐火性能有限元分析

为了研究型钢混凝土框架整体结构的耐火性能,为其抗火设计提供参考,采用受火楼层建立精细化有限元计算模型、非受火楼层建立梁单元计算模型的方法,建立了型钢混凝土框架整体结构的耐火性能计算模型。考虑火灾位置、荷载分布形式、柱轴压比等参数的影响,对火灾下型钢混凝土框架整体结构的变形规律、承载机制、破坏形态以及耐火极限进行参数分析。分析结果表明：火灾下框架结构出现了整体破坏和局部破坏两种典型的破坏形态,受火构件受到的约束作用对其耐火性能有较大的影响;在局部破坏形态中,由于受热膨胀,火灾下框架梁首先出现了较大的轴压力,受火框架梁处于压弯受力状态;之后,框架梁出现了悬链线效应,轴力对框架梁的受力状态有较大影响;在整体破坏形态中,根据轴压比及荷载分布形式的不同,框架出现了中柱破坏和边柱破坏两种典型破坏形态,同时,随楼层受火位置的升高,柱的轴压比减小,框架结构的耐火极限增加。     

硅灰石和膨润土增强膨胀型钢结构防火涂料

合成具有改善钢结构耐火性能的膨胀型涂料的新配方,涂料配方基于硅灰石和膨润土增强的可膨胀石墨,根据硅灰石和膨润土含量及不同研磨时间配制了十种膨胀型涂料配方。结果表明：随着填料（硅灰石和膨润土）含量和研磨时间增加,炭膨胀率增加,同时能够减少热源向钢板基材的热渗透。X 射线衍射（XRD）分析表明残炭中含有硼酸铝,硼酸铝具有很高的热稳定性,能增强涂料的耐火性能。随着填料含量和研磨时间增加,残炭中碳含量增加、氧含量减少、磷含量增加,较高比例的磷能够有助于增加碳质炭的形成。较高填料含量和研磨时间能够增加残余重量和耐火性能。     

浅谈钢结构抗火计算方法

对钢结构抗火设计的意义、建筑室内火灾的发展与温度变化进行了介绍，主要对钢结构在火灾条件下反应分析的有限元方法及其研究成果进行综述，并且指出了钢结构高温设计分析的发展方向。     

钢结构防火涂料施工质量控制的探讨

对钢结构建筑工程中防火涂料的应用进行了概述,并以某钢结构办公楼防火涂料施工完成后存在的问题进行了探讨和分析,指出对钢结构防火涂料施工质量的控制进行探讨,有着很重要的实际应用意义。     

建筑钢结构防火设计的规范理解与软件应用

以往钢结构防火设计更多的是从建筑层面的防火构造措施来解决.结合对《建筑钢结构防火技术规范》(GB51249-2017)的理解,由理论切入,到紧密契合防火规范和软件应用,全方位地介绍了建筑钢结构防火分析与.设计的实现方法.首先从结构层面阐述了钢结构防火设计的三种方法,其次介绍了钢结构防火设计在midas Gen中的实现流...     

公安消防部队如何做好重大灾害事故抢险救援

统计了2009年公安消防部队参加的全部27起重大灾害事故抢险救援,从人员伤亡、事故类型、参与部门、消防出动力量、持续时间等7个方面分析重大灾害事故抢险救援的特点和规律,并针对这些特点和规律,对公安消防部队如何做好重大灾害事故抢险救援进行探讨,对提高公安消防部队重大灾害事故抢险救援能力具有一定的现实指导意义。     

预应力钢桁架火灾响应及火灾后受力性能试验研究

对4榀空间预应力钢桁架结构模型进行火灾下的结构响应及火灾后力学性能试验研究。模型选用奥氏体304无缝不锈钢管制作,张拉钢索采用7×12+IWR镀锌高强钢绞线,通过置于模型下端中心处的伸缩小立柱施加预应力。结构模型两端简支,另两边自由。试验测定了火灾下桁架弦杆和腹杆的温度响应及上弦节点位移,并对火灾后尚未破坏的结构模型进一步进行原位卸载及加载试验。研究结果表明：预应力不锈钢桁架模型在受火过程中,虽然张拉钢索产生一定的松弛,但结构模型未出现整体坍塌;火灾后的预应力钢桁架产生一定的残余位移,且对于相同几何尺寸和受火条件的结构模型,二次张拉施加预应力的结构模型火灾后残余位移小于一次张拉模型;对于具有较大刚度的结构,张拉次数及最高受火温度对预应力不锈钢桁架的火灾后弹性极限荷载没有影响。