Reconstruction of the Grenfell Tower fire – Part 4: Contribution to the understanding of fire propagation and behaviour during horizontal fire spread

The tragic events at Grenfell Tower in 2017, involving a combustible façade system, have raised concerns regarding the fire risk that these systems pose. In this series of articles, so far published, fire development inside the initial apartment has been investigated using an appropriate computational fluid dynamics (CFD) model. Several scenarios including different fire sources and ventilation conditions were addressed. Fire propagation through the window to the external façade and to higher apartments was modelled. This model was validated by comparing the numerical results with the visual observations reported in the Grenfell Inquiry. A CFD model of the complete east face of the Grenfell Tower was then created. This paper details CFD modelling of the complete Grenfell Tower façade during the late horizontal phase of fire spread. As the physics of lateral flame spread is different from that for upward flame spread, it is important to assess the validity of the model, thus far developed, for this configuration. Fire propagation over the whole façade is modelled and compared with observations from the real disaster. This provides a better understanding of its fire behaviour and of the contribution of architectural details and their impact on fire spread.     

塔设备计算机辅助强度计算及校核

利用Visual Basic语言编制塔设备强度计算及校核的计算机辅助设计软件,包括筒体、封头强度计算,塔设备的强度校核,材料库的建立及开孔补强计算等,同时还具有计算及校核文档自动生成功能。该程序能够缩短塔设备的设计周期,提高工作效率。     

改善结构设计,提高大型平面近场测试设备精度探讨

本文论述了改善结构设计 ,提高大型平面近场测试设备各单项精度及传动精度的可行性 ;分析了主要部件合理的结构对精度及其它方面的影响     

铁塔构件材料合理代用的分析计算

叙述了铁塔构件材料合理代用的原则,对构件在不同受力状态下材料代用进行了理论分析计算,为铁塔制造厂材料代用提供了理论依据。     

基于小波和奇异值理论的西安钟楼模态参数识别

在对国家重点文物保护单位西安钟楼进行强噪声环境激励下振动监测的基础上,应用自然激励法采用不同测点的传感器记录的加速度信号的互相关函数代替系统的脉冲响应函数,选取适当的小波函数、小波尺度、中心频率和带宽频率对互相关函数进行小波分析,并根据小波变换系数的模的相角和对数导数识别频率和阻尼比信息,实现了基于小波和奇异值理论的方法对西安钟楼模态参数进行识别,并对识别结果进行对比分析,验证基于小波和奇异值理论的方法识别古建筑木结构模态参数的可行性,为古建筑的保护和研究工作提供参考。     

新型干法水泥厂窑尾塔架的结构选型

近十年来,由于大规模水泥厂窑尾塔架跨度大,单根梁柱的内力大,钢结构梁柱和钢管混凝土柱因其特有的性能优势得到了广泛的应用。结合近30年的工程实践,总结了新型干法水泥窑窑尾塔架设计的结构选型,分析了在不同背景条件下窑尾塔架各种结构形式的适用范围和性能特点。     

高效波纹填料塔在甲醇精馏分离中的应用及前景

本文通过高效网孔波纹填料塔在12000t/a甲醇生产装置中成功应用的实例,阐明将高效网孔波纹填料塔应用于甲醇精馏过程能取得良好的效果。与浮阀塔等塔设备相比具有节能降耗、降低塔高、保护环境等优点。     

风偏角与杆塔结构对500kV同杆双回线路绕击耐雷性能的影响

分析500kV双回输电线路的绕击耐雷性能,对EGM进行了改进。在计算过程中为考虑风的影响,引入风偏角;同时引入了雷击避雷线与雷击地面击穿强度比值随杆塔高度h变化的系数β。用暴露弧法计算每根导线绕击跳闸率,以暴露弧为0时对应的雷电流作为雷电的最大绕击电流,并分析了风偏角、杆塔结构等因素对500kV双回输电线路各导线绕击跳闸率的影响。结果表明,风偏角增大,绕击跳闸率增大;总绕击跳闸率随避雷线横担增长而减小;各导线绕击跳闸率与杆塔结构间的关系复杂,需具体计算分析。理论分析和计算验证了该方法的实用性和有效性,具有一定的工程指导意义。     

古建筑高台基对地震反应的影响

高台基是许多古建筑重要的组成部分,为了探讨高台基对结构地震反应的影响,本文以西安钟楼为研究对象,建立了台基与上部木结构共同作用的三维有限元模型,采用振型分解反应谱法进行了地震反应分析,得到了对结构进行地震反应分析时应取的振型数目,与不考虑高台基时的动力特性和地震反应做了对比,并对不同侧移刚度高台基的影响进行了分析．结果表明,古建筑高台基使萁上部结构的地震反应放大,地震反应分析必须考虑高台基的影响．     

An investigation of slewing-crane dynamics during slewing motion—development and verification of a mathematical model

Information about the dynamic loading of a steel structure is important for its static design as well as for an assessment of its fatigue life. In the case of tower cranes, these loads are mainly caused by vibrations and load sway, which occurs as a result of the slewing motion of the jib around the vertical axis and from the radial movement of the load's suspension point. In this paper, only the slewing motion that produces the spatial motion of the pendulum is considered, because this kind of motion has received much less attention than the translation of the suspension point. In order to achieve this, a non-linear mathematical model of the load sway during the slewing motion was formulated, and the non-linear nature of the swinging motion for large angles and the non-linearity of the power transmission were considered. The structure's elasticity and damping, the friction in the main bearing, and the air resistance were also taken into account. The dynamic forces acting on the steel structure of the crane during payload transport were obtained. In order to confirm the mathematical model, an actual model of a crane was built and used as the basis for measurements. A comparison of the results shows good agreement between the predicted and the measured values.