Post-fire behaviour of high strength steel endplate connections — Part 2: Numerical study

• Numerical study was performed on high strength steel (HSS) endplate connections after fire.
• Behaviour and failure mode of HSS endplate connections after fire were simulated.
• Validation against the experimental results was carried out.
• FE model is verified appropriate to simulate HSS endplate connections after fire.
• Basis for accurate evaluation and safe reuse of HSS endplate connections after fire is offered.

In this paper and its companion paper, a perspective of using high strength steels to take place of mild steels in structural design of endplate connections is proposed and investigated. The endplate is made of high strength steels while the beam and the column are made of mild steels. This paper presents a numerical study conducted using ABAQUS on high strength steel endplate connections after cooling down from fire, to reveal more information and better understanding on the post-fire behaviour of high strength steel endplate connections. The validation of this numerical modelling against all representative experimental results was performed on moment–rotation relationship, failure mode and yield line pattern of endplate connections, where it is found that good agreements exist. Hence this numerical analysis method can be employed with reasonable accuracy to predict the behaviour of high strength steel endplate connections after cooling down from fire. This finite element analysis provides an efficient, economical, and accurate tool to investigate the post-fire performance of high strength steel endplate connections, which can be further developed for the parametric study and post-fire evaluation of an entire steel structure with high strength steel members. This study offers a basis for structural engineers to perform accurate evaluation and safe reuse of structures with members made of high strength steels after fire.