AN INVESTIGATION ON THE EFFECTIVENESS OF NAILED TIMBER WALLS AS RETROFITTING MEASURE FOR SUBSTANDARD CONCRETE STRUCTURES

Türkiye is in a seismically active region and has suffered through extensive losses due to several major earthquakes that struck its various parts. The destructive effects of earthquakes in Türkiye are infuriated by the large volume of buildings constructed with low-quality materials and workmanship. Especially a great percentage of residential buildings are constructed by using substandard concrete and reinforcement. Furthermore, research shows a great possibility of a high magnitude earthquake to occur in the near future around the Marmara region, which includes the most populated cities in Türkiye. Inevitably, there is a need for an effective and affordable retrofitting method. In this study, a new retrofitting method is introduced and its effect on the seismic performance of two representative case study buildings are investigated. The first case study building, is a building with substandard material quality but well-designed according the recent earthquake design codes. The second case study building, instead, is a building with low material quality and poorly designed. The retrofitting method consists of reinforced concrete frames infilled by cross-laminated timber walls made with Turkish strength graded local wood-Pinus nigra-. Wood lamellas are nailed and not glued like in traditional cross-laminated timber. This in order to reduce panels costs and make them more economically affordable first, but also to reduce the in-plane rigidity of the wall panels in an effort to master the impact of the walls corners on the reinforced concrete beam-column nodes. Initially, cyclic shear tests have been performed on two types of nailed timber walls to obtain relevant stiffness and strength properties. The only difference between the nailed timber walls was the number of nails used. Simulations of each case study reinforced concrete buildings retrofitted with the two types of nailed timber walls were conducted along with the original reinforced concrete building. Computational simulations were conducted in CSI Perform3D using ideally-equivalent buckling restrained brace elements. Finally, the seismic performances of structural models have been compared with each other.