EVALUATION OF STRUCTURAL BEHAVIOR AND MECHANICAL STRENGTH OF MULTIPLE-LEAF MASONRY WALLS AT JEDDAH'S HERITAGE BUILDINGS UNDER UNIAXIAL COMPRESSION LOADS AND THEIR APPROPRIATE STRENGTHENING TECHNIQUES

The current work represents the results of the intensive experimental study of the outer leaves of the multipleleaf load bearing masonry walls in Jeddah's heritage buildings at Kingdom of Saudi Arabia (KSA). It studies the structural behavior and mechanical properties of the walls and their stone units under uniaxial compressive standard tests. Besides, it evaluates their strengthening and retrofitting by using a number of techniques, mainly, bedjoints reinforcement and nanolime injections. The fossil if erouslimestones of these heritage buildings are characterized by very high porosity and shell-formation inside. Although, the big number of heritage buildings in Jeddah (more than 500), there is very few studies concern the present research field. Standard mechanical tests were conducted for stone and mortar cubic samples, in addition to nine masonry prisms that represent the heritage walls. Results showed the low intrinsic mechanical strength and behavior of these walls and its constituting main building materials, which requires strengthening. The paper proved the great advance of applying injection with nanolime mortar than reinforcement of bed-joints to enhance structural behavior and strength.