日本新建筑标准的结构抗火设计

本的目的是为了说明1998—2000期间日本建筑规程(日本建筑标准)以及相关技术标准的修订。考虑了功能要求后，规程修订趋向于以性能为主。在抗大这一章节中，功能要求指的是在发生火灾时防止结构倒塌以及火势向其他隔问的蔓延，同时还包括防止火势由失火建筑物内部向周围建筑的扩散。为了满足功能上的要求，我们提供了三种方法(A、B、C)。方法A是传统的设计方法，即建筑框架及隔墙采用防火构件。相对于方法A，新近引进了以考虑性能为主的方法B。在方法B中，由一系列设计公式计算出指定部分发生火灾可能产生的后果、结构和边界部分的热反应、构件破坏的临界时间。设计公式应足够简单，以便于建筑工程师和有关官员的使用。由方法B计算出的结果通常是保守的。方法C是一个框架，用最先进的设计方法。规程没有指定采用的设计方法，但是工程上火灾和结构分析的结果只有在全面地考证后才能被行业接受。     

结构连续性对钢筋混凝土柱耐火极限的影响

国内外现行规范有关钢筋混凝土柱抗火设计的相关规定,几乎都是基于单个构件的研究结果而制定的,由于火灾中相邻构件之间的相互约束,使得约束柱与无约束柱的火灾行为存在本质区别。利用有限元软件SAFIR,本文首先分析了无约束钢筋混凝土柱对应ASTME119标准升温曲线的力学性能,并与其他学者的试验结果进行了对比。随后,针对约束柱耐火极限的不同定义,分析了转动/轴向约束程度对柱耐火极限的影响规律。     

考虑结构和热力学参数的钢梁抗火性能预测

给出预测标准火灾条件下钢梁耐火时间的公式。首先,根据热力学特性找出影响钢梁抗火性能的关键参数,然后将其划分为结构参数或热力学参数。通过完全耦合热力学数值分析方法,研究发生大变形前各参数对耐火性能的影响。在进行广泛的参数分析前,利用试验结果验证了数值模拟的准确性。通过多元线性回归分析,得到各种设计条件下钢梁抗火时间的预测公式。统计分析表明,所提出的公式是有效的。详细说明了该公式在实际消防设计中的应用,也介绍了该公式的优点。     

Numerical Modelling and Benchmark Study of Fire Resistance of Stainless Steel Structural Elements

Fire Technology - The validation of numerical models, for the behaviour of structures in case of fire, is crucial for the development of precise and safe design rules for members at elevated...     

Evaluation of the Fire Resistance of 19th Century Iron Framed Buildings

To assess the fire resistance of historical buildings, information is needed about the applied materials, the construction details, etc. Starting from this information calculation models can be set up to determine the fire resistance of the total structure and its components. Assessing cast iron framed buildings is difficult because cast iron as well as the former construction techniques are no longer used. Nevertheless the contemporary Eurocodes (EC) can be helpful when renovating such buildings. This article goes deeper into the structural characteristics of Brussels 19th century iron framed industrial buildings. Two calculations illustrate how the EC can be applied to evaluate the fire resistance of the structure.     

某厂房火灾后构件检测与评估

通过对近期某在建厂房火灾后结构构件的检测与评定,为该厂房结构灾后安全性评估和灾后加固修复提供了可靠且充分的检测数据资料,并为今后类似结构火灾后检测与评估提供了可借鉴的检测方法与检测数据.     

A Probabilistic Model for Fire Detection with Applications

A probabilistic model for estimating the activation time of ceiling-mounted fire detection devices is described. The probabilistic model builds on the deterministic model, DETACT, by introducing probability distribution functions in place of point estimates for the parameters governing fire detector response, including the fire heat release rate history, the detector activation temperature, response time index and conductance parameter and the location of the device. The probabilistic model incorporates only parameter uncertainty. Model uncertainties associated with the deterministic model for estimating the activation time of ceiling mounted fire detectors have not been addressed. An example application of the probabilistic model is discussed. The probabilistic results provide valuable insights about the relevant parameters involved in a time to detection analysis.     

Potential of Surrogate Modelling for Probabilistic Fire Analysis of Structures

Fire Technology - The interest in probabilistic methodologies to demonstrate structural fire safety has increased significantly in recent times. However, the evaluation of the structural behavior...     

An Improved Probabilistic Approach for Fire Detection in Videos

This paper proposes an improved probabilistic approach using two improved feature representations. These features are color and motion. First, an improved probabilistic model for color-based fire detection is proposed, and candidate fire regions are generated from this model. Then, an improved motion feature is used for final decision. The performance of the proposed approach showed about 0.2758 accuracy in false positive rate, and 0.2636 accuracy in false negative rate on a benchmark fire video database, which represents a decrease of 46.6% in false positive rate, and a decrease of 52.1% in false negative rate compared to the probabilistic approach.     

无机板防火隔墙耐火性能研究

通过对几种不同结构方式的无机板防火隔墙进行耐火极限试验,对相关数据进行分析,总结出影响此类构件耐火性能的主要因素,并提出提高此类构件耐火性能的一些建议。     

Probabilistic Fire Simulation Assessment Using Simplified Model and Zone Modelling of a Kitchen Fire Scenario

Fire Technology - Probabilistic fire simulation has been gaining interest in performance-based design approach. Very few evaluations on modelling performance can lead to...     

德国威达钢结构防火屋面系统

描述了国内外防水材料的防火标准和国内外有关屋面系统防火规范的要求及现状,介绍了德国威达钢结构防火屋面系统优异的防火、保温隔汽、稳定以及使用寿命长等性能,推荐了威达的两套防火系统方案,分别具有板岩卷材面层及彩钢板面层.     

某建筑物火灾后结构损伤评估与加固方案

某9层钢筋混凝土框架结构房屋在6、7层发生火灾,该两层的钢筋混凝土构件受到不同程度的损伤,本文评估火灾对该房屋的损伤程度,并提出相应的加固方案.     

Monitoring Structural Health Using a Probabilistic Measure

A Bayesian probabilistic methodology for structural health monitoring is presented. The method uses a sequence of identified modal parameter data sets to continually compute the probability of damage. In this approach, a high likelihood of a reduction in model stiffness at a location is taken as a proxy for damage at the corresponding structural location. The concept extends the idea of using as indicators of damage the changes in model parameters identified using a linear finite-element model and modal parameter data sets from the structure in undamaged and possibly damaged states. This extension is needed because of uncertainties in the updated model parameters that in practice obscure health assessment. These uncertainties arise due to effects such as variation in the identified modal parameters in the absence of damage, as well as unavoidable model error. The method is illustrated by simulating on-line monitoring, wherein specified modal parameters are identified on a regular basis and the probability of damage for each substructure is continually updated. Examples are given for abrupt onset of damage and progressive deterioration.     

高强度混凝土的耐火性能研究

高强度混凝土(HSC)具有强度高,空隙率低,抗渗性好,耐久性好等优点,在建筑工程特别是高层建筑中被广泛采用。但是,与普通混凝土相比,高强混凝土的耐火性能较差,特别是火灾中的抗爆裂性能较差。该文从工程应用的角度出发,结合国外的研究成果,对高强混凝土(HSC)的耐火性能进行探讨,将为高强度混凝土抗火设计提供参考。     

Design Fire Characteristics for Probabilistic Assessments of Dwellings in England

In England, there are no fixed requirements on the parameters adopted when considering residential design fires, and analyses undertaken are often deterministic with limited consideration given to probabilistic assessments and the sensitivity of parameters. The Home Office dwelling fires dataset has been analysed, considering the fire damage area and the time from ignition to fire and rescue service arrival. From this, lognormal distributions for the maximum heat release rate (HRR) and fire growth rate of residential fires have been approximated. The mean maximum HRR ranges from 900 kW to 1900 kW, with a standard deviation ranging from 2000 kW to 3700 kW, depending on property type and room of fire origin. The mean growth rate, assuming a t2 relationship, ranges from 0.0022 kW/s2 to 0.0034 kW/s2, with a standard deviation ranging from 0.0071 kW/s2 to 0.0132 kW/s2. When considering incidents which result in immediate fire and rescue service call out following ignition, the mean growth rate increases to a range of 0.0058 kW/s2 to 0.0088 kW/s2. As a result of the analyses, design fire distributions are provided which can be adopted for probabilistic assessments. For deterministic analyses, it is proposed that an approximate 95th percentile fire may be adopted, aligning with a medium growth rate of 0.0117 kW/s2 and a maximum fuel-limited HRR in the region of 3800 kW to 4400 kW, depending on whether the dwelling is a house or an apartment. A 95th percentile design fire broadly aligns with values already specified in guidance, helping to substantiate the existing recommendations.     

火灾下钢管混凝土柱承载力研究

参照日本规范,推导了适用于我国钢管混凝土柱的抗火验算公式,并对本文公式和按常用参数回归得到的公式进行了比较,最后采用对某大厦钢管混凝土柱进行了火灾下的承载力验算.2004年出版的《矩形钢管混凝土结构技术规程》CECS159：2004,给出了矩形钢管混凝土抗火验算方法,但关于圆形钢管混凝土构件目前尚无相应的抗火计算方法.