Performance of Cellular Composite Floor Beams under Severe Fire Conditions

尽管目前大跨度组合楼盖体系很流行，但现行的结构防火工程设计规范EC3/4 Part 1.2和BS5950 Part 8并未对采用蜂窝状钢梁的组合楼板的耐火性能作出规定或提供指导。本项目的目的是研究足尺复合蜂窝楼板梁在高温下的性能和破坏机理，包括单独和组合在一起的弯曲和剪切影响。还将着重研究当梁在火灾中加热时，由轴向约束引起的附加压缩力对周围结构随之而来的热膨胀的发展和影响。这项拟议的研究是基于阿尔斯特的物理模型火灾试验计划，以提供丰富的数据，这些数据将极大地提高对组合蜂窝钢梁在火灾中性能的了解水平。这一方法将通过将计算机建模与测试相结合来扩展和加强，最初是为了验证和合理化行为，但导致了一项广泛的参数研究，旨在为火灾中的此类构件开发设计方法。在使用暴露在火灾中的钢质CBS的复合地板上提供合理的设计指南，将使人们能够在合理和可信的基础上计算防火要求，这是目前尚不存在的，并将为英国顾问和制造商带来可能的全球出口机会。

Despite the current popularity of long-span composite flooring systems, the current structural fire engineering design codes EC3/4 Part 1.2 and BS5950 Part 8 do not contain rules or guidance on the fire resistance of composite floors employing cellular steel beams. The purpose of this project is to investigate the performance and failure mechanisms of full-scale composite cellular floor beams at elevated temperatures over a range of spans, including the influence of both flexure and shear, alone and in combination. Emphasis will also be placed on examining the development and influence of the additional compression forces caused by axial restraint to thermal expansion ensuing from the surrounding structure when a beam is heated in a fire. The proposed research is based on a programme of physical model fire tests at Ulster, to provide a wealth of data which will greatly enhance the level of understanding of behaviour of composite cellular steel beams in fire. This approach will be extended and enhanced by the integration of computer modelling with the testing, initially for validation and rationalisation of the behaviour, but leading to an extensive parametric study aimed at developing a design methodology for such members in fire. The availability of sound design guidance on composite floors using steel CBs exposed to fire would make it possible to calculate fire protection requirements on a rational and trustworthy basis which does not exist at present, and would lead to possible worldwide export opportunities for UK consultants and fabricators.