Numerical Modelling of Timber Braced Frame Masonry Structures (Dhajji Dewari)

Abstract

This paper presents numerical modeling technique for Dhajji-Dewari structures (timber-braced rubble stone masonry), and its application for the evaluation of in-plane force-deformation capacity of Dhajji wall panels of different configuration of bracings. Dhajji structures are mainly composed of vertical and horizontal timber posts and braced using diagonal bracings and horizontal studs. Wall openings are filled with random rubble masonry in week mortar. These types of structures are known for their high lateral deformability and are mostly found in Kashmir and its surrounding areas both in Pakistan and India, locally named as "Dhajji-Dewari". A numerical model of Dhajji wall was developed using a finite element based structural seismic analysis program SeismoStruct, based on the experimental study carried out at the Earthquake Engineering Center of UET Peshawar. In-plane force-deformation response of Dhajji wall was evaluated through static pushover analysis, and validated with the measured response. The numerical model was extended to evaluate and compare the lateral strengths of Dhajji walls of three different configurations of bracings. This can enable structural designer to select Dhajji wall with a particular bracing configuration keeping in view the required lateral strength and deformability with least possible quantity of timber for construction, which might be helpful to economize the construction of these structures.