Journal of Composites for Construction

This paper presents a quantitative economic analysis and a qualitative constructability analysis of three-dimensional fiber-reinforced plastic (FRP) reinforcement cages for concrete beams. Material, labor, and life-cycle costs are provided, and construction practice aspects are discussed. The results of the analyses indicate that prefabricated FRP cages can offer benefits to the construction industry. Although the initial costs of the FRP materials are likely to be higher than those of steel rebar, there is a significant potential for cost savings due to reduced maintenance and labor costs, as a result of the corrosion resistance of the FRP and the increased construction productivity. When direct life-cycle costs are considered, FRP reinforcements already constitute, in many cases, an economically competitive alternative to conventional steel reinforcement in adverse environments. If, in addition, the indirect cost savings as well as quality and safety issues are considered, the FRP reinforcement may be even more competitive.

The “Design Guidelines of FRP Reinforced Concrete Building Structures” was established in 1993 as one of the final outputs of the research committee on fiber-reinforced plastic (FRP) reinforced concrete building structures organized under the Japanese Ministry of Construction's research and development project titled: “Effective Use of Advanced Construction Materials (1988–92).” These Guidelines are a translation of the Japanese guidelines. They describe the design concept for nonprestressed concrete structures reinforced with FRP rebars, and the calculation equations are all relegated to the commentaries due to lack of design data on FRP reinforced concrete structures. A limit-state design method has been adopted under the guidelines. Among the subjects covered are overview, design method, materials, loads and combination, stress and deformation, ultimate state design, serviceability state design, structural requirement, and testing methods for the tensile strength and bond strength of materials. “The Design Guidelines for FRP Prestressed Concrete Members” is separate from these guidelines.

Low tensile strength restricts use of natural stone in applications where tensile or flexural capacity is required, such as for long spans or thin sections (e.g., cladding, countertops, desktops). In addition, exposure to agents of chemical and mechanical weathering can decrease the strength of stone over time. The use of composite laminates as external reinforcement to increase the tensile and flexural capacity of natural stone is investigated. High strength (HS) carbon/epoxy laminates were bonded to the lower surfaces of marble and limestone beams, and flexural tests were performed on reinforced and unreinforced specimens. Results indicate that external composite reinforcement can increase the load-carrying capacity of both types of stone by an order of magnitude as compared to unreinforced control samples. Laminate thicknesses of four plies [0.5 mm (0.02) in.] and eight plies [1.0 mm (0.04) in.] produced similar increases in stone strength. However, stone reinforced with four-ply laminates experienced greater deflection before failure than samples reinforced with eight plies.

This paper presents the experimental and theoretical characterizations of mechanical properties of glass fiber reinforced plastic (GFRP) wide flange and box beams. Static response of pultruded beams was studied by conducting a total of 187 tests and evaluating shear influence, shear lag, warping, and manufacturing quality. Experimental results revealed that fiber asymmetry and interfacial slip between fabric layers affect the beam stiffness. Experimental observations of shear lag and warping phenomena have been discussed. Test results showed that interfacial slip between adjacent glass fabric layers had a significant influence on strain measurement. Shear deflections were found to be significant in relation to bending deflections. Computations of bending and shear stiffness of GFRP beams using simplified theoretical expressions have been summarized with an example. Moment versus curvature (M−ϕ) relationships for the test beams exhibited a linear relationship nearly up to failure. Failure patterns for wide flange and box beams under static loads are described.