Journal of Composites for Construction

Several national programs define the testing protocols and design guidelines for fiber reinforced polymer (FRP) reinforcement in concrete structures. This paper offers a review of these documents, comparing the materials testing and design philosophies for FRP reinforcement of different working groups. The work references Canadian, European, and Japanese efforts to codify these materials and assess the relative merits of each approach. The emphasis is on prestressing applications since the demands for sustained load capacity and full bond are more severe than for reinforced concrete.

Presented in this paper are results of an experimental investigation pertaining to the short-term behavior of concentrically loaded fiber-reinforced polymeric composite slender members. Tested members had box and I-shape cross sections and were pultruded using a vinylester matrix containing flame retardant additives reinforced with E-glass roving and nonwoven mats. Material properties for each tested member are used in a limit state predictor equation to correlate the experimental and the predicted results. Design guidelines and a step-by-step example are also presented.

A combined analytical and experimental evaluation of flexural-torsional and lateral-distortional buckling of fiber-reinforced plastic (FRP) composite wide-flange (WF) beams is presented. Based on energy principles, the total potential energy equations for instability of FRP WF sections are derived using the nonlinear elastic theory. For the analysis of lateral-distortional buckling, a fifth-order polynomial shape function is adopted to model the deformed shape of web panels. The models are validated by testing two geometrically identical FRP WF beams but with distinct material architectures produced by the pultrusion process. The beams are tested under midspan concentrated loads to evaluate their flexural-torsional and lateral-distortional buckling responses. To detect rotations of the midspan cross sections and onset of critical buckling loads, horizontal transverse bars are attached to the beam's flanges, and the bar ends are connected to linear variable differential transducers (LVDTs). For the same purpose, we use strain gauges bonded to the upper and lower surfaces near to the free edges of the top flange. A good agreement between the proposed analytical approach and experimental and finite-element analyses results is obtained, and simplified engineering equations for flexural-torsional buckling are formulated. The proposed analytical solutions can be used to predict flexural-torsional and lateral-distortional buckling loads for other FRP shapes and to formulate simplified design equations.

The use of fiber reinforced plastic (FRP) panels to reinforce wood and wood composites, particularly glued laminated timber (glulam), has gained acceptance by the wood industry recently. The reinforced glulam exhibits substantial advantages in its structural and economical performance. The FRP used in the glulam reinforcement is in thin panel form with a thickness of 0.05–0.095 in. It is composed of 100% unidirectional high modulus fibers, such as aramids, carbon, or fiberglass. The fibers are embedded in a thermosetting plastic matrix in either pure or hybrid form. The fiber to resin ratio is approximately 66% by volume. Physical, mechanical, and durability properties are the most interesting properties for practice engineers and manufacturers to know. To select appropriate test methods for the evaluation of these properties is crucial for the ensuring of accurate design values. The intention of this paper is to provide a rational model for other engineers, researchers, and manufacturers to use in bringing FRP products into infrastructure and building construction places. This paper evaluated and recommended selection of existing test methods. FRP has been tested using selected test methods. Data gathered from these tests are reported in the paper.

In this paper a recent rehabilitation project completed in Italy using carbon fiber reinforced plastic (CFRP) unidirectional sheets is examined. This technology was selected for the strengthening of a doubly curved, precast, prestressed concrete (PC) shell. The shell was part of the roof of an industrial building and had experienced severe localized damage due to accidental heat radiating from a flue. The selection of the CFRP system involved the screening of different repair procedures with relation to the constraints imposed by the owner: limited disturbance to the industrial process, safety of the occupants, low cost, and durability. In addition, the damaged PC shell was located in the center of the industrial building and did not allow the use of a crane for its replacement. This project demonstrates that the utilization of new materials can provide owners/designers with effective solutions to challenging restoration problems.