Design of FRP retrofitting under out-of-plane bending

Abstract

The severity of damage possible in unreinforced brick masonry (hereafter termed ‘masonry’) construction subjected to high levels of out-of-plane loading has been well demonstrated in recent times. Due to the large global building stock of masonry structures, it is essential that efficient methods for retrofit of masonry structures be developed. The use of efficient fibre-reinforced polymer (FRP) strips has been shown to improve the loadcarrying and displacement capacities of masonry sections subjected to out-of-plane loading. This paper presents principles for design of masonry elements strengthened with vertically oriented FRP strips and subjected to out-of- plane bending. Design considerations are given, along with recommendations based on experimental observations. Design variables discussed include retrofitting technique (i.e. externally bonded or near-surface mounted), FRP material (i.e. carbon or glass) and FRP placement (i.e. relative to mortar joints). A design methodology for masonry retrofitted with vertical FRP strips with intermediate crack (IC) debonding as the failure mode is also presented.