Fire Performance of HSS Steel Connections

背景：火灾会导致温度升高，从而对建筑构件和系统产生不利影响。钢结构节点是任何钢结构的重要组成部分。火场观测证实，由于节点的分力作用，对结构构件的存活时间有很大影响。众所周知，中空钢型材比厚钢型材吸收热能的速率更高，从而导致更早的屈服。在火灾发生时，受约束的钢梁会迅速升温，并对支撑柱产生横向推力。目的：本研究的目的是检验和评估现有高强钢绞线到高强钢绞线延伸式端板弯矩连接在火灾条件下的性能，并致力于引入一种能够吸收或重定向侧向推力的新的连接方式。科学方法：使用中等和全尺寸试验，评估现有的和建议的高强钢绞线到高强钢绞线延伸式端板弯矩连接在火灾条件下的性能。提出的研究重点是如何利用火灾中的接触网作用来改善约束钢梁的耐火性能。采用ABAQUS有限元模型分析了热工性能和结构性能的耦合效应。在卡尔顿大学新建的消防设施中，设计火灾(商业和工业用房)和标准时间-温度分布都将应用于连接。这项研究有望促进对常用钢连接(而不是孤立连接)火灾行为的了解，并提出一种先进的连接，可以增强火灾发生时的稳定性。研究结果将用于建立梁柱节点的抗火设计方法。

Background: Fires can cause elevated temperature that can have adverse impact on the building elements andsystems. Steel connections are vital and essential components of any steel structure. Observations from firesconfirm that connections have considerable effect on the survival time of structural members due to their rolein distributing forces. Hollow Steel Sections HSS are known to absorb heat energy at higher rates than thicksteel sections, causing earlier yielding to occur. In a fire event, restrained steel beams can heat up quickly andcause lateral thrust on supporting columns. It is likely that columns fail because of this thrust, and notnecessarily because of the elevated temperatures.Objectives: The proposed research aims to examine and evaluate, under fire conditions, the performance ofexisting HSS-to-HSS extended end-plate moment connections and work towards introducing a new connectioncapable of absorbing or redirecting the lateral thrust.Scientific approach: Using medium- and full-scale experiments, the performance of current and proposedHSS-to-HSS extended end-plate moment connections in fire conditions will be assessed. The proposedresearch focuses on how to utilize the catenary action in fire in order to improve the fire performance ofrestrained steel beams. ABAQUS finite element model will be used to analyze the couple effect of thermal andstructural performance. Both design fires (for commercial and industrial type occupancies) as well as standardtime-temperature profiles will be applied to the connections using a newly constructed fire facility at CarletonUniversity's.The research is expected to advance the understanding of fire behaviour of the commonly used steelconnections (not isolated connections), and propose an advanced connection that can enhance the stability inthe event of fire. The results will be used to produce a fire resistance design method of beam-to-columnconnections.