SIMPLE STRENGTHENING TECHNIQUES AND NEW TECHNOLOGIES FOR SEISMIC SAFETY OF EXISTING BUILDINGS: RECENT RESEARCH AND APPLICATIONS IN TURKEY

Experiences show that many older reinforced concrete and masonry buildings suffered heavy damages during earthquakes due to their poor construction materials and non-ductile structural systems. Hence a need of new materials and technologies to be used to at least save lives; especially in crowded buildings such as hospitals and schools. In this paper, simple, fast and economical safety measures and strengthening techniques are proposed. The proposed safety measures is to install lightweight steel panels in specified locations in the structure to reduce inter-story drifts and prevent structural collapse. Furthermore specially manufactured technical textile and polyurethane glue, is proposed to save life and prevent collapse of non-structural masonry walls during a seismic event with a minimum cost. Shake table tests on full scale specimens were conducted to verify these techniques. Also parallel braced steel frame strengthening technique is proposed to strength low or middle raise buildings. In this technique all the construction works are applied from outside of the building and do not affect the building function. The idea is to reduce the earthquake displacement demand on the structure by attaching steel frames to the building floors. These frames are parallel to the structural system of the building and their foundations are connected to the existing building’s foundation. Two study cases in Istanbul were strengthened using this technique. The first one is a factory building and the other is a historical masonry building. Analysis and strengthening projects details are presented. Finally seismic retrofit of Tarabya Hotel in Istanbul is presented to shows the benefits from using new technologies such seismic isolation in improving the seismic performance of existing buildings. Tests and analysis results confirm the effectiveness of the proposed techniques.