On the evening of Saturday February 12 2005 a fire
broke out in the Windsor tower in Madrid, Spain. The
building is located in the heart of Madrid's commercial
and banking centre and is one of the tallest in the
capital.
The Madrid fire has increased interest in the real
response of structures to fire, coming so soon after
major building fires in New York, Chicago and London,
amongst others.
The following is an Arup view based upon what is
known about the fire event in conjunction with our
structural fire design and analysis experience.
It has been prepared based upon information in the
public domain only and will be updated as further
information becomes available.
Structure and fire safety measures
The building had a concrete central core with two
rows of reinforced concrete columns in the north-south
direction, aligned with the core side walls. The structure
above ground was characterised by two transition floors
at 3rd and 17th Floor levels, which housed plant and
services.
The typical floor slab construction was reinforced
concrete bi-directional ribbed slabs, spanning onto
composite steel beams in the east-west direction.
The slabs were supported along the perimeter by steel
columns, supplemented by RC columns on two sides below
17th Floor level.
The transition floors were formed with solid RC slabs
and deep beams. The original facade mullions and transoms
were fixed to the steel perimeter columns, and a new
facade structure had been added to outside of old
facade. The perimeter columns in turn were supported
by transition structures at 17th and 3rd Floor levels.
Spanish codes, in common with most continental European
codes, place more emphasis on passive control measures
than on active measures. The Madrid regional code
does not require sprinkler protection for buildings
with an evacuation height of less than 100m so active
measures were limited to automatic detection and alarm,
fire hose reels and a dry riser system.
The building was being refurbished
at the time of the fire so we do not know the
state of the passive measures in place but from
information available it would appear that Edificio
Windsor had the following passive protection:
floor by floor compartmentation (typical compartment
size 850 m2)
An unspecified fire resistance period for the
concrete structure, steel columns protected
below 17th Floor, unprotected above that level.
Vertical shafts forming separate compartments
1.0m or 1.5m deep vertical fire protection
along the perimeter slab edge.
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