M.A. ElGawady1
1 Dept of Civil and Environmental Engineering, University of Auckland , Private Bag 92019, Auckland , New
Zealand, melg003@ec.auckalnd.ac.nz
ABSTRACT
This paper presents an analytical model for in-plane shear behaviour of unreinforced masonry (URM) walls retrofitted using fibre reinforced polymers (URM-FRP). The proposed model idealizes masonry, epoxy, and FRP in a URM-FRP as different homogenous layers. Then, using principles from the theory of elasticity, the governing differential equation of the system is formulated and solved. A simple computer program was developed to combine the solution of the differential equations with material nonlinearity. The material nonlinearity was represented by step-by-step layer stiffness degradation; after each step the equations are resolved linearly. The proposed basic analytical model allows the fundamental investigation of in-plane shear behaviour of URM-FRP. Effects of epoxy allowable shear stresses and FRP axial rigidity on the shear strength of URM-FRP are examined. In addition, comparisons with three existing models are carried out. Finally, the model shows that there is a threshold with respect to the axial rigidity of the FRP beyond which no increase in shear strength is expected. In other words, adding masonry lateral resistance to the FRP contribution to the shear strength as recommended by existing models is correct up to a certain limit beyond which this addition is not valid.
KEYWORDS: FRP, composites, epoxy, shear analysis, retrofitting, earthquake
5b-2
