Page 89 - Vertical City

CONSTRUCTION OF THE TOWERS 89

If total protection does not exist, whatever the
height of the buildings, it is now possible to make them
resistant to defined terrorist attacks 7.

It concerns primarily the security of persons, whether
inside or outside the building, which has to be ensured.

Thus, the structure is divided into compartments
in such a manner that, the occupants evacuated, each
can support an explosion or the complete cycle of a
fire (from ignition to natural extinction), without com-
promising the integrity and the habitability either of the
building or its neighboring compartments and without
necessarily having to call out the fire department.

This implies containment of the thermal effects and
the spread of smoke and flames in the affected zone.

Traditional constructions in earth or in brick, even in
concrete, easily resist even the most severe fires. This
is not the case for structures in wood (that also make
high-rise buildings possible) and even less so for those in
steel, which require protection.

The steel structure of the first high-rise buildings
were protected by boarding or coatings based on
asbestos, and these from the end of the 19th century,
and still in certain countries until the end of the 20th
century despite the danger of breathing asbestos fibers
having been proved since 1890.

7 EUROCODE EN 1990 (2003) states in section 2.1 (4)P: “A struc-
ture must be designed and constructed in such a way that it is not
damaged by events such as an explosion, a shock and consequences
of human error, in a disproportionate manner to the initial cause.
Events to take into account are those agreed for a specific project
with the client and the competent authorities”.