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

三面防火保护常用于工业设施，在防火结构梁的无保护上法兰上铺设管道支架、设备支架、格栅等。对带有三面防火保护的单荷载梁的耐火测试表明，过早破坏发生了，与要求的耐火持续时间相比，这可以迅速发生。然而，测试证据并不能反映比单梁更复杂的实际工程结构，而且坊间证据表明，在实际火灾中没有发生过失败。该项目将研究具有三面保护的梁的实际耐火性能，包括实际情况下的温度变化以及未包括在炉膛耐火测试中的次要构件的抑制作用。该项目的结果将用于制定指导方针，用于评估现有或新的结构设计是否适合进行三面保护。目标是：-在不同火灾和热流条件下计算截面关键温度的简化方法；-验证计算关键温度的简化方法-二级构件提供的横向扭转屈曲约束水平-评估横向扭转屈曲抗力的方法-防火和结构布局的优化这项工作将结合数值模拟，防火测试和分析开发，以及由赞助公司进行的防火测试。项目的新颖之处在于，提出了经火灾试验验证的三面防火截面关键温度的简化计算方法，深入理解了实践中遇到的各种侧向约束的三面防护钢梁的侧向扭转屈曲和LTB阻力计算的设计方法，并将新知识应用于结构构型和防火方案的优化设计。

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.