THE ROLE OF WOODEN ELEMENTS FOR IMPROVING SEISMIC PERFORMANCE AND CRACKING PATTERNS OF MASONRY WALLS

Masonry buildings are the most common type of structures in Iran. In spite of their proper compression strength, due to fundamental weakness caused by lack of enough confinement, they are vulnerable during the earthquakes. To improve their seismic performance, various methods have been provided to reinforce and retrofit them, in recent years. There are enough evidence to show that performance of masonry walls has been improved by the placement of wooden elements in the masonry walls. Timber framed buildings are well known as an efficient seismic-resistant structures popular all over the world due to not only their seismic performance, but also for low-cost and ease of access to them. Timber framed buildings generally consist of masonry walls reinforced by horizontal and vertical timber elements. This paper deals with a numerical study on the structural performance of timber framed masonry walls. The 3D models are generated with the ANSYS program to perform parametric analysis. The models are validated based on the relevant experimental results. After a number of verification of numerical models of different combinations of masonry wall and timber elements, the load-displacement graph of reinforced walls is extracted. The nonlinear static analysis is used to perform a generation of the program. Then, the impact of wooden elements on strength properties and changing the patterns of cracking in walls in four separate models have been investigated. Non-linear laws for the materials, such as a bilinear stress-strain curve for monotonic loading of timber, and a Mohr-Coulomb contact law for wooden members are used. Hill's yield criterion is adopted to make the timber element models. The William-Warnke yield criterion is adopted for masonry walls. Finally, non-linear static analyses of four existing timber framed masonry walls are performed. In wooden elements of each model, stress intensity distribution, equivalent plastic strain distribution, and de-bonding have been studied. The results have shown that in spite of the low utilization of those masonry walls and wood capacity, the patterns of cracks have been changed, and the ultimate bearing capacity and ductility in the timber framed masonry walls have been increased.