Post-Fire Seismic Analysis of Moment Resisting Frame with Seismic Stability Designs & Fire Protection Method

Abstract

Research is ongoing to explore methods to enhance connection design to ensure the structure can
withstand high temperatures. This study explores improving connection design for high
temperature resistance in fire-exposed moment-resisting frames using seismically stable tubular
RBS and Stub beams. Research on the post-fire seismic behaviour of stable connections is limited,
with recent studies showing that Tubular RBS and Stub beam components perform better in
moment-resisting frames. However, their behaviour in a fire still needs to be determined. Large
beam-column members in fire-exposed steel buildings that remain reasonably straight with no
visible distortion are fit for reuse as per codes. This study evaluates the future seismic
performance of steel buildings that survived a fire event with little or no distortions. Building
structures typically employ passive and active fire protection methods to protect structural
elements from potential fire hazards. This research also studies intumescent coatings' behaviour
and protection efficiency in seismically stable designs of Tubular RBS and stub beams through fire
exposures. On MRFs with tubular RBS and stub beams, finite element analysis was done, and
damage was induced by FEMA cyclic loading protocol. The Quiel and Garlock Fire curve, created
based on the One Meridian Plaza fire event, is chosen for the proposed study to represent the best
post-earthquake fire scenario. Field analyses of MRFs with and without seismic stability designs
are contrasted by providing fire exposure. There is also a comparison of intumescent coating
efficiency with and without protection. TW-RBS showed a significant improvement in drift capacity
compared to regular connection with the fire, increasing it from 2% to 6%. This change in drift is
more important than that indicated by codes for the IMF and exhibits drift capacity as SMF. When
a stub beam connection is utilized, it has been observed that it can improve the drift capacity by
1% and moment capacity by 2% compared to regular connections. This means the structure can
better resist bending moments than lateral forces when using stub beam connections.