Title:Study on the Fire Resistance of Concrete-filled Steel Tubular Column to
Composite Beam Joints after Earthquake Damage
Volume: 2
Author(s): Guo-Qiang Wei, Sun-Hang Ji, Wen-Jing Mao and Wen-Da Wang*
Affiliation:
- School of Civil Engineering, Lanzhou University of Technology, Lanzhou, China
Keywords:
Concrete-filled steel tube, composite beam joint, post-earthquake fire, finite element analysis, damage modes, fire resistance.
Abstract:
Background: Post-earthquake fire is one of the secondary disasters caused by the
earthquake; many earthquakes around the world have brought about severe fires and led to
enormous losses. It is of great significance to study the fire resistance of structures after earthquake
to improve the level of urban disaster prevention and reduce the fire loss.
Methods: A nonlinear finite element model of composite joints subjected to post-earthquake
fires is established based on ABAQUS software. The state after the earthquake damage is imported
into the thermal-stress analysis model through the restart request in ABAQUS, and considered
as the initial state of the thermal-stress analysis model.
Results: It is noticed that when the damage index is less than 0.517, the damage level shows
significant effect on the fire resistance, but the influence is no longer significant when the damage
index reaches 0.781. When only the column is exposed to fire, the column showed obvious
local buckling and overall bending deformation. Meanwhile, when the joint area below the concrete
slab is exposed to fire, the joint shows a mixed failure mode of the excessive vertical displacement
of beam end and column instability.
Conclusion: The fire resistance of the composite joint decreases gradually with the increase of
seismic damage level. The fire condition has a significant effect on the fire resistance of the
composite joints; with the increase of fire area, the fire resistance of composite joints with same
damage degrees decreases gradually.