UC Researching Change Of Building Method To Reduce Fire Risk
UC Researching Change Of Building Method To Reduce
Fire Risk
November
9, 2012
The University of
Canterbury (UC) is researching how high-rise buildings can
cope best if a fire break out.
High-rise buildings normally require
fire resistance of 60 minutes or more to facilitate rescue
and prevent structural collapse, UC engineering researcher
Dr Tony Abu said today.
In the light of the collapse of the
World Trade Center (WTC) towers in 2001, a lot of emphasis
has been placed on understanding the overall behaviour of
buildings exposed to fires.
In particular it was important that the
whole structure was tied-in properly to ensure that the loss
of one member does not result in a disproportionate collapse
of the entire building, he said.
Recent research has shown that fire
resistance of multi-storey steel-framed buildings with
composite floors is considerably improved if the effect of
slabs is taken into account.
``Traditionally, steel buildings have
been designed for room-temperature conditions and covered
with protective material to limit member temperatures to
550°C when exposed to the standard furnace fire. However,
if these buildings are tied together appropriately then some
of the floor beams can be unprotected to generate more
stable buildings in the event of
fires.
``The
floors of the WTC were supported on steel trusses which had
been protected with sprayed-on cementitious material. The
impact of the planes shook most of the protection off the
trusses. They then lost strength as they heated up,
eventually not being able to support their loads, leading to
the collapse of floors onto the ones beneath, and the
eventual pancake failure seen in the videos.’’
Dr Abu said the
new approach was performance-based design, which selects the
most economical solution that meets the required fire
resistance criteria. In the case of steel buildings,
considerable savings can be made in fire protection
costs.
``The
research at UC is aimed at developing simplified design
methods that incorporate the advanced approach. At the
masters level, we are investigating potential failure
mechanisms, while our undergraduate students are evaluating
the limitations of existing methods.
``In light of the high potential for
the occurrence of fires that cannot be extinguished or
controlled to a fairly small size after an earthquake, our
research seeks to develop routine simple design solutions
based on fundamental behaviour to help advance the design of
all types of structures for fire
conditions.’’
ENDS