Abstract:
The post-fire response of partially restrained steel connections is characterized by the
reduction in strength after exposure to a full heating-cooling cycle of a fire event. This
reduction in strength constitutes one of the crucial factors in assessing the structural
performance of partially restrained steel connections post-fire exposure. This study
proposes a methodology for investigating the post-fire response of bolted top and seat
angle connections, which are widely used in steel buildings. To achieve this, finite
element (FE) models are developed in ABAQUS. The methodology consists of, first, the
development of FE beam-to-column connection designed to survive a fire event. The
outcome is to compute the post-fire thermal axial forces while varying different geometric
and load parameters that impact the behavior. Second, the computed post-fire thermal
axial force, along with the post-fire mechanical properties, are both used in developing
FE component connection models, which are then subjected to loading until failure.
The results show that after a fire event, the load-bearing capacity of the top and seat angle
connection decreases with higher fire temperatures. The decrease in connection capacity
ranges from 30% to 87% of its initial strength after exposure to post-fire temperatures
ranging from 200℃ to 500℃, respectively.
This methodology represents a significant step in assessing the remaining capacity of
steel connections post-fire and offers preliminary data to support the development of
design guidelines, offering engineers guidance on assessing the need for replacement or
repair of structural members after a fire event. Further experimental work is
recommended to investigate different connection configurations, in order to gain a better
understanding of the percentage reduction in capacity for this type of connection.
