The Turkish town of Erzincan in North-Eastern Anatolia was struck by a magnitude (M5) 6.8 earthquake on 13 March 1992. Severe damage was inflicted on the exposed building stock resulting in the death of about 2500 people with 9000 injured and an estimated economic loss of 250 million pounds Sterling. This paper briefly reviews the structural effects of the earthquake and the observed defects. This is followed by a discussion of the assessment and inspection philosophy developed by the authors under the auspices of a World Bank-funded reconstruction project managed by the Turkish Ministry of Reconstruction. It is concluded that repetitive patterns of damage observed during field missions alongside newly-developed 'capacity design' criteria may be
used to formulate comprehensive, yet easy-to-use, inspection forms.
These were used extensively by teams of engineers working on the
reconstruction programme and have been most successful in providing
the necessary data for repaired and retrofitting strategies. A typical multi
storey RC structure from Erzincan is used to demonstrate possible repair
scenarios, including techniques for selective intervention proposed by the
Engineering Seismology and Earthquake Engineering Section at Imperial
College. The response of the frame, in its original, conventionally
repaired and selectively-repaired states, is analysed using the nonlinear
dynamic analysis system ADAPTIC. It is shown that selective repair
provides an opportunity to tune the structural response for optimum
displacement and ductility demands distributions, thus reducing the
vulnerability of structures in future earthquake episodes. |
