Establishing safety distances for wildland fires

In wildland fires, safety zones should be considered concerning people who are intervening in the emergency or attempting evacuation. To establish such zones, the solid flame model, together with the view factor calculated from a previously selected equation, was used to estimate the thermal radiation emitted by the flame front of a wildland fire. After determining the flame heights yielded by the 13 fuel types in the Rothermel classification for surface fires, and for crown fires in various Mediterranean forests, the thermal radiation was calculated for each scenario as a function of the distance. These data, together with threshold values for the vulnerability of people (protected or unprotected) and houses to thermal radiation, allowed for a set of safety distances for different situations to be obtained. These safety distances can be applied both in territory planning and in emergency situations.     

基于强度折减的边坡动力安全系数确定方法研究

地震边坡稳定性分析已成为岩土工程界和地震工程界抗震减灾研究的重要课题之一。通过数值分析对土质边坡地震动力响应规律进行研究,发现边坡上PGA分布突变点的连线与潜在滑动面位置存在较好的对应关系。据此可通过PGA分布突变点的连线轮廓来大致确定边坡的潜在滑裂面,同时,这些PGA分布突变点可以选定为判定坡体临界稳定状态的关键点。基于强度折减法,以关键点的相对位移作为边坡动力破坏的控制性指标,结合地震特征位移和安全系数来评价边坡的动力稳定性,以特征位移与强度折减系数曲线上的特征位移产生突变时对应的强度折减系数作为边坡的地震动力安全系数。     

基于温度预测模型的供暖系统热源预测控制

分析了实现建筑节能的控制策略。设计了较为先进的基于温度预测模型的供暖系统热源最佳起始时间自适应控制器。利用MATLAB和SI MULINK对具体对象进行了仿真实验,预加热时间的预测值误差未超出预计范围。结果表明,基于温度预测模型的热源系统自调节控制器能够良好运转,与传统控制方法相比较,具有更好的操作性能,能够实现建筑节能的目的。     

GisFFE—an integrated software system for the dynamic simulation of fires following an earthquake based on GIS

Fires following earthquake (FFE) are dangerous secondary disasters occurring after large earthquakes, leading to severe property and life losses in certain cities with dense wooden buildings. In order to explore the complicated behavior of fire-spread and to assess the fire-induced losses after a large earthquake scenario, an integrated software system based on GIS (called GisFFE) was developed to perform a dynamic simulation of FFE. The purpose of this paper is to introduce the details of GisFFE, including its architecture, models and simulation flow, and to present a case study. The architecture of GisFFE consists of 4 components: an urban geo-database, a model library, a simulation center and outputs. The urban geo-database provides basic spatial and statistical data used in the GIS platform for FFE simulation; the model library contains three sub-models (ignition, fire-spread and fire-suppression models), which correspond to the three key stages involved in FFE; the simulation center serves as an operation center that integrates data and models; after the simulation is complete, statistical maps and charts are the resulting output.     

一种改进的Pasternak地基模型及层合地基板的解析解

从三维弹性力学基本方程出发,建立了正交异性材料层合板的状态方程,并提出一种改进的Pasternak弹性地基模型,给出了四边简支层合地基板的解析解。此解满足层合板的基本方程和层间连续条件,适合任意厚跨比,计及了所有材料常数,考虑了基底切向接触应力的影响。算例讨论了地基参数对几种地基模型的影响。计算结果表明,随着地基刚度的增大,剪应力的影响是不可忽略的。     

A model for earthquake risk management based on the life-cycle performance of structures

Over 50 years of design life, buildings are exposed to different magnitudes and frequencies of earthquakes that require consideration of life-cycle cost (LCC). The LCC entails quantifying the building performance under seismic hazard and investments throughout the life of the structures. Traditional LCC utilises probabilities of being in different damage states. However, for buildings with inherent irregularities (e.g. vertical irregularity and plan irregularity), these probabilities are not readily available. In this paper, a system-based approach, utilising fuzzy set theory, is used to quantify the possibility of being in different damage states. The analysis is limited to study the effect of seismic exposure on the building LCC. The proposed method is illustrated with two case studies, a six-storey reinforced concrete (RC) building located in Vancouver, Canada, and vulnerability of an urban centre with 1000 RC buildings. Furthermore, sensitivity analysis is carried out to highlight the impact of different building performance modifiers on the LCC.     

A new model based on experimental results for the thermal characterization of bricks

The development of fast and reliable protocols to determine the characteristics of building materials is of importance in order to develop environmentally friendly houses with an efficient energy design. In this article heat flux evolution on different types of clay and concrete bricks has been studied using a guarded hot-plate. The studied bricks were purchased from local commercially available sources and included a solid face brick and a range of honeycombed and perforated bricks. From the data collected a new model to study heat flux is proposed. This model is based on the shape of the typical sigmoidal curves observed for the time dependent heat flux evolution. The model allows the calculation of the thermal resistance (R) and the heat flux in the steady-state (φ_∞). The model also calculates two new parameters, t_B and τ_B. t_B represents the time at which half φ_∞ is attained. This parameter (t_B) has additionally been found to be dependent on the thermal diffusivity and the geometric characteristics of the brick.     

A model for the frequency of extreme river levels based on river dynamics

A new model for predicting the frequency of extreme river levels is proposed which encapsulates physical knowledge about river dynamics. The central idea is the use of continuous time stochastic processes that use hydrological equations and ergodic theory to model extreme events, rather than relying on statistical fits of classical models to local maximum data. A simple example shows how changes in discharge characteristics change the extreme river level frequencies. Solutions are provided for special cases, and directions for more general techniques are provided.     

基于熵权的模糊评价模型在建筑方案优选中的应用

以建筑工程的综合评价为基础,结合建筑工程的特点,分析和归纳了影响建筑工程方案优选的因素指标.提出熵值理论与模糊建模相结合的项目评价方法,建立了基于熵权的模糊评价模型.引用信息熵所反映数据本身的效用值来计算指标的权重系数,有效地避免了权重分配困难的问题.以某建筑工程为背景,基于专家经验对该项目方案进行了优选,取得了预期的结果.     

混凝土结构耐久性的未确知—AHP综合评估模型

根据混凝土结构耐久性包含众多未确知性的特点,选择最能影响结构耐久性的因素作为评估指标,定义了指标未确知测度以及指标对确定构件耐久性等级所起作用大小的指标分类权重,建立了构件耐久性未确知综合评估系统;采用层次分析法,计算各构件对整体结构耐久性的重要性权重.建立了未确知综合评估系统与AHP相结合的混凝土结构耐久性评估模型.应用实例表明,所建模型的正确性和适用性.     

New model for performance prediction in fixed-bed reactors based on the approach of the unused bed zone

In the present study a practical model useful for designers dealing with pilot scale reactors for pollutant control has been developed. Investigations were undertaken for a single-component lead study on New Zealand clinoptilolite at the temperature of 25+/-1 degrees C. Fifteen runs under different operating conditions such as particle characteristics (expressed as d*(p)/D), column geometry (as l*/D) and flow speed (as R*e) have been performed. The results were interpreted by a response surface method (RSM) from which an equation giving the unused bed zone (UBZ) was obtained. From those dimensionless parameters, a sequence of contour plots was drawn, making it easy for a designer to choose optimum design parameters while controlling the operation performance. The flow rate (R*e) range was established over the laminar flow conditions from 1 to 8, (l/D*) was extended from 7 to 20 and (d(p)/D*) varied from 3% to 10%. Optimization of performance of the reactor as UBZ could vary from 10% to 40% of the material operating capacity.     

基于实体模型的基桩动测曲线ABAQUS数值模拟及其应用

本文旨在探索一种可靠的基桩动测曲线数值模拟方法,在此基础上对基桩动测曲线做进一步的分析。文中介绍了基桩动测原理,分析了实体模型数值模拟的必要性。应用ABAQUS软件建立了桩土实体模型,计算得到相应的模拟曲线。归一化对比模拟曲线与模型桩动测曲线,发现两者有较好的一致性。通过ABAQUS模拟出大量数据,为进一步结合小波分析...     

基于AutoLISP的三维模型快速建立与精度分析

建筑物的三维模型是数字城市重建的重要组成部分,而建筑物高精度三维模型的快速建立一直是三维数字仿真亟待解决的问题。本文通过无协作目标电子全站仪采集建筑的三维坐标,基于AutoLISP实现了数据的导入、建筑物墙面的拟合、特征点的投影及门窗等构件的自动生成,从而快速生成建筑物的三维模型,并对生成的建筑模型进行精度分析。基于AutoLISP构建建筑物的三维模型,大大提高了建模速度;并能有效控制三维建筑模型的质量。     

基于桁-拱叠加模型的体外预应力混凝土梁抗剪承载力计算方法

通过剪力传递途径分析和结构拓扑优化,揭示了桁架-拱模型可以反映体外预应力混凝土梁主要受剪承载机理。通过桁架模型和拱模型的叠加,建立了体外预应力混凝土梁的抗剪承载力简化计算方法。公式形式简单,能够反映结构的受力机理,包含了梁的几何尺寸、剪跨比、配箍率、轴向预应力、混凝土强度、荷载形式等影响因素。公式可以统一考虑无腹筋梁和有腹筋梁,不同的剪跨比,以及体内体外混合配束的情况。应用本文方法与国内外已有试验进行对比,表明计算值与试验结果吻合良好且偏于安全。最后,通过参数分析得出了主要因素对抗剪承载力的影响规律。     

A new model for evaluating the dynamic shear strength of rocks based on laboratory test data for earthquake-resistant design

The dynamic shear strength of rocks is required for the earthquake-resistant design of nuclear power plants in Japan.This research aims to propose a mathematical model for estimating the dynamic strength and to validate the model.Two different types of specimens were prepared for the model validation,and the monotonic and cyclic loading tests were conducted to obtain the mathematical model parameters.Subsequently,multistep cyclic loading tests were performed,followed by simulations using the mathematical model.The test results demonstrated that the dynamic shear strength exceeded the static shear strength,which agreed with previous researches.Furthermore,the dynamic shear strength calculated using the mathematical model was generally consistent with that obtained from the experimental data.     

控制冻土融化容许值的建筑物通风管基础计算方法

根据传热理论,在现有JGJ118—98《冻土地区建筑地基基础设计规范》中采用的无通风管基础的冻土地基的最大融化深度的计算公式基础上,推导出有通风管基础按容许地基土逐渐融化原则设计的冻土地基最大融化深度的计算公式,首次提出了等效地面温度和等效地面温度系数的概念。首次建立室内采暖条件下通风管复合基础的传热数学模型,并在此模型基础上采用有限单元法对通风管复合基础进行数值模拟分析结合理论推导的方法,得出不同室内地面温度、不同通风管间距时的通风管基础中心下的温度沿深度分布曲线及54个等效地面温度数据,依据最小二乘法原理对以上数据拟合出工程广泛采用的通风管直径为300mm的通风管基础的等效地面温度系数计算公式,从而提出建筑物通风管基础通风面积计算方法,由实际工程设计验证了该计算方法的可靠性与实用性。     

我国居家养老型住宅套型模式探讨

居家养老是我国现阶段大力推行的养老方式,探索适合于居家养老的住宅模式是建筑设计领域面临的必然课题。本文分析了老年人对住宅空间的生理、心理要求,对老年家庭结构下的居住模式进行了分类和研究,提出了满足居家养老需求的独住型、同住型、邻居型、分而不离型四种主要的居住模式,归纳出了各种居住模式的特征,设计出对应的套型模式简图,并据此总结出居家养老住宅套型模式的特点。     

无卤高阻燃型铝塑复合板在高层建筑外墙装饰应用上的防火安全性试验与材料应用研究

本文采用中等尺寸多层建筑燃烧试验方法（NFPA285）和高层楼房大型实体火灾的实景试验等新方法,取代传统的难燃级小型试验（GB/T8625）和单体燃烧SBI中型试验（GB/T20284）等试验方法,研究了无卤高阻燃填充芯料选作防火铝塑复合板芯材取代普通不阻燃聚乙烯芯村的防火特性差异,并从试验结果参数对其燃烧性能的影响进行了评价分析,因而对防火铝塑板在高层建筑幕墙装备上的材料选用有一定的指导意义。