ABSTRACT
Abstract Using equilibrium, compatibility and a bilinear concrete stress-strain diagram the stress distribution within the FRP 2-D grid reinforced member is modeled to assess potential failure modes. Model analysis is compared to laboratory tests performed on flat slabs, 4' x 10' (1.22 m x 3.05 m), three point loaded, simply supported, and monotonically loaded [1]. Strain readings were taken at four locations, gauges at each location were installed on the concrete compression surface and directly beneath on the top and bottom surfaces of the grid bars. Force transfer develops in FRP 2-D grid reinforced concrete members by bearing on the transverse grid bar [2]. A compressive force is transmitted to the concrete on one side of the transverse bars and a tension crack may form on the other side, compression stresses resist the differential in the longitudinal bar forces. Keywords: Fiber reinforced plastics, grids, concrete members, stress and strain
1 Properties of NEFMAC 2-D Grid
NEFMAC longitudinal and transverse bars can be fabricated using different fiber materials, grid spacings and cross sections [3]. Similar bars and equal grid spacings were used in the grid longitudinal and transverse bars used in the test slabs. NEFMAC grids are identified using a letter and a number. The letter indicates the type of fibers and the number corresponds to the diameter in millimeters of an equivalent grade 60 steel reinforcing bar. For example, a C22 grid is composed of carbon fibers with a longitudinal bar strength equivalent to a 22 millimeter steel bar; an H22 is a hybrid grid composed of 10% carbon and 90% glass fibers, total fiber content by volume is approximately 40%. The area and mechanical properties of typical grids are given in Table 1 [4].
