SEISMIC RETROFIT DESIGN OF HISTORIC CENTURY-OLD SCHOOL BUILDINGS IN ISTANBUL, TURKEY

摘要

This paper presents a seismic retrofit design and implementation plan for two of the historic century-old school buildings located on the campus of Robert College of Istanbul in Turkey. The four and five-story buildings have unreinforced concrete bearing walls along their perimeters, which are connected by reinforced concrete floor slabs to steel framing encased in concrete in the buildings' interior. The thick perimeter walls of these Beaux-Arts style buildings resist most of the lateral loads. Seismic hazard at the school site was evaluated. Structural analysis showed that the buildings' perimeter wall piers have insufficient in-plane shear and bending capacities to resist seismic demands, especially in the buildings' transverse direction. The proposed retrofit design employs the use of horizontally oriented carbon fiber reinforced polymer (CFRP) composite fabrics on the interior and exterior faces of the buildings' perimeter wall piers and vertically oriented CFRP fabrics on the jamb faces of the wall piers. CFRP anchors in conjunction with the vertically oriented fabrics are recommended to develop the tensile strength of the vertical fibers into the pier-to-spandrel joints. A site investigation was performed to identify the buildings' architectural features, structural details, and mechanical systems to devise a retrofit scheme that minimizes the impact on these systems and preserves the buildings' historic fabric.Architectural impact is minimized by strategically placing the CFRP fabrics on the wall piers that have exterior surface offsets, and selecting a finish material that allows the CFRP fabrics to blend in with the other bare concrete wall surfaces.