Enhancing Lateral Load Performance of Traditional Timber Wall (Dhajji-Dewari) by Strengthening of joints

Traditional timber structures, known as Dhajji Dewari, are mostly found in the Northern areas of Pakistan and Kashmir. Very limited research is available to validate the seismic performance of Dhajji Dewari construction. It has experimentally been proved that Dhajji construction is suitable for earthquake resistance and the prominent features include its affordability, superficial ability to tolerate earthquakes and the fact that it is within the technical means of local, less skilled personnel for house building. This paper presents experimental work conducted on typical Dhajji Dewari wall found in northern areas of Pakistan and Kashmir, to evaluate the in-plane lateral load response by strengthening of critical joints. The experimental work includes in-plane monotonic testing on four reduced scale walls, one wall was used without any strengthening (Conventional wall) other walls were strengthened by different strengthening techniques (bamboos, metal strips, and metal gusset plates). Test results show that the connection functionality, particularly at the joint of vertical posts and bottom plates, controls the overall performance of the wall. Strengthening of these joints not only enhances the lateral load carrying capacity of the wall, but also significantly augment the energy dissipation capacity of the system. Further, based on cost benefit analysis it is concluded that wall strengthened with metal strips give the best reinforcement of Dhajji walls keeping in view the additional cost of strengthening and load deformation behavior of wall.