A study of the effectiveness of 3-sided fireproofing protection for structural beams in hydrocarbon fires

三面防火保护通常用于工业设施，其中管道支撑、设备支撑和格栅铺设在防火结构梁的未防护的顶部法兰上。对带有三面防火保护的单梁进行的耐火测试表明，会发生早期破坏，而且与所需的耐火持续时间相比，这可能是快速的。然而，试验证据并不能反映比单梁更复杂的真实工程结构，而且坊间证据表明在真实火灾中没有发生破坏。本项目将研究具有三面保护的梁的实际耐火性能，包括现实场景中的温度变化以及未包括在炉膛耐火试验中的次要构件的约束效果。这个项目的结果将被用来制定指南，用于评估现有的或新的结构设计是否适合三面保护。目标是：-简化计算不同火灾和热流条件下横截面关键温度的方法；-验证计算关键温度的简化方法--次级构件提供的侧向扭转屈曲约束水平--抗侧向扭转屈曲的评估方法--防火和结构布局的优化工作将结合数值模拟、火灾试验和分析开发，并由主办公司进行火灾试验。该项目的新颖之处包括通过火灾试验验证的三面防火截面关键温度的简化计算方法，对实践中遇到的各种侧向约束的三面保护钢梁横向扭转屈曲的深入理解，以及抗力计算的设计方法，以及新知识在结构配置和消防方案优化设计中的应用。

3-sided fireproofing protection is commonly used in industrial facilities, where pipe supports, equipment supports, and gratings are laid on the unprotected top flange of a fire protected structural beam. Fire resistance testing on single, loaded, beams with 3-side fireproofing protection shows that premature failure occurs, and that this can be rapid compared to the required fire resistance durations. However, test evidence does not reflect real engineered structures which are more complex than single beams, and where anecdotal evidence suggests that in real fires failures have not occurred.This project will investigate realistic fire resistance performance of beams with 3-sided protection, including temperature developments in realistic scenarios and restraining effects of secondary members that are not included in furnace fire resistance testing. The result of this project will be used to develop guidelines that can be used for assessing whether an existing or new structural design is a suitable candidate for 3-sided protection.The objectives are:- simplified method of calculating key temperatures in the cross-section under different fire and heat flux conditions;- validation of the simplified method of calculating key temperatures- Level of lateral torsional buckling restraints offered by secondary memebrs- Method of evaluating lateral torsional buckling resistance- Optimisation of fire protection and structural layoutThe work will combine numerical modelling, fire testing and analytical development, with the fire testing to be carried out by the sponsoring company.The novelty of the project includes a simplified method of calculating key temperatures in the cross-section with three-side fire protection validated by fire testing, deep understanding of lateral torsional buckling of 3-side protected steel beams with a variety of lateral restraints encountered in practice and a design method for calculating the LTB resistance, and application of the new knowledge in optimal design of structural configuration and fire protection scheme.