Analysis and modelling of the seismic behaviour of high ... - Ingegneria

5. SEISMIC BEHAVIOUR OF RC COLUMNS EMBEDDING STEEL PROFILES
et al., 1999; Aschheim, 2000; Scawthorn, 2000). Estimates for economic losses
were around 20 billion US dollars. The official death toll was over 17,200, with
some 44,000 people injured and thousands left homeless. Some 77,300 homes
and businesses were destroyed, and 244,500 were damaged. The majority of
deaths and injuries were in the cities of Kocaeli, Sakarya, and Yalova, as
reinforced concrete moment-resisting frame buildings behaved poorly during the
earthquake.
According to official estimates, more than 20,000 moment frame buildings
collapsed, and many more suffered moderate to severe damage. Three- to seven-
storey apartment buildings were hard hit, although many were constructed in the
past 20 years. These buildings were probably designed and detailed to comply with
the requirements of the building code (TS-500 code, 1975) and of the earthquake
Turkish code (1975) for construction in a first-degree seismic zone. Nevertheless,
the ductile reinforcement details described in the 1975 earthquake code were
rarely observed in buildings inspected after the August 17 th 1999 earthquake.
Moreover, many of the failures and collapses of engineered construction observed
by the reconnaissance team, and reported in Sezen et al. (1999), can be attributed
to the formation of soft first storeys as a result of differences in frame systems and
in-fill wall geometry especially between the first and upper stories; to the realisation
of non-ductile details; and to the utilisation of material of too poor quality in some
cases. It was clear that the Turkish earthquake code provisions were rarely
enforced for the engineering of commercial and residential construction. On the
basis of the aforementioned consideration, this last research activity, conducted in
the third year of the Ph.D. course, is part of another European Project (INERD
Project), promoted by the E.U. through the E.C.S.C. European Coal and Steel
Community and R.F.C.S. Research Fund for Coal and Steel, that deals with the
improvement of the resistance and ductility of reinforced concrete (RC) structures
using the performance of structural steel profiles.
5.2 The INERD project
The European INERD (acronym of Innovations for Earthquakes Resistant Design)
project consists in promoting one specific construction measure for lower storeys of
RC structures, by which steel profiles would be encased in the RC columns in
order to provide them with a basic reliable shear and compression resistance. The
general objective is to establish an innovative concept through new standard
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