“CROSSWALLS ” INSTEAD OF SHEARWALLS A Proposed Research Project for the Retrofit of Vulnerable Reinforced Concrete Buildings in Earthquake Areas based on Traditional Hımış Construction

This paper will describe the parameters for a proposed research project to develop a design for the structural retrofit of particularly vulnerable reinforced concrete (RC) structures. This design is inspired by the characteristics of the traditional construction practice in timber and masonry infill-frame known in Turkey as hımış. The purpose of this proposal is to apply some of the basic philosophical ideas derived from an examination of earthquake damaged hımış infill-frame buildings that resisted collapse in the same earthquakes that leveled so many of their modern counterparts, and apply these ideas to the design of an economical retrofit scheme for the vulnerable reinforced concrete (RC) infill buildings. The basic objectives of this proposed retrofit design are that it should (1) be economical to install, (2) cause minimum disruption to the existing occupants of the buildings (installation without vacating the building or the individual residential units), (3) provide as much damage control as possible together with collapse prevention. To achieve this goal, this paper proposes that existing and new infill walls in vulnerable RC residential buildings be subdivided with studs and cross-pieces, and that new walls be constructed with lime-based mortar of lower strength than Portland cement mortar so that the elastoplastic behaviour of the infill will have a lower initial stiffness combined with higher “ductility ” and stability. Figure 1: “Pancake ” collapse i