Fiber-reinforced polymer (FRP) composite materials been widely used in civil engineering new construction and repair of structures due to their superior properties. FRP provides options and benefits not available using traditional materials. The promise of FRP materials lies in their high-strength, lightweight, noncorrosive, nonconducting, and nonmagnetic properties. ACI Committee 440 has published reports, guides, and specifications on the use of FRP materials for may reinforcement applications based on available test data, technical reports, and field applications. The aim of these document is to help practitioners implement FRP technology while providing testimony that design and construction with FRP materials systems is rapidly moving from emerging to mainstream technology.

This volume represents the thirteen in the symposium series and could not have been put together without the help, dedication, cooperation, and assistance of many volunteers and ACI staff members. First, we would like to thank the authors for meeting our various deadlines for submission, providing an opportunity for FRPRCS-13 to showcase the most current work possible at the symposium. Second, the International Scientific Steering Committee, consisting of many distinguished international researchers, including chairs of past FRPRCS symposia, many distinguished reviewers and members of the ACI Committee 440 who volunteered their time and carefully evaluated and thoroughly reviewed the technical papers, and whose input and advice have been a contributing factor to the success of this volume.

This article presents the results of a research program on the behavior of masonry walls reinforced with FRP bars subjected to out-of-plane loads. The article also proposes a preliminary protocol for the flexural design of masonry walls reinforced with FRP bars. The objectives of this investigation were: (1) evaluate the flexural behavior of masonry walls reinforced with FRP bars subjected to out-of-plane loads, and (2) develop preliminary design recommendations. Ten masonry walls, 2 m [6.6 ft] high, were subjected to out-of-plane loads, tested under quasi-static loading cycles. The test specimens included walls constructed using concrete and clay masonry units, reinforced with Glass FRP (GFRP) and Carbon FRP (CFRP) bars in different configurations. All the FRPreinforced masonry walls showed a bilinear moment-deflection curve with one steep slope up to cracking of masonry and a decrease in stiffness after cracking. The majority of the walls failed due to crushing of masonry in the compression side. After failure occurred and as the out-of-plane load was progressively removed, the walls returned to a position close to the initial vertical position. In general, the approaches used to calculate flexural strengths and deflections provided good agreement with the experimental results.

Synopsis: This study presents the experimental and theoretical response of 10 simply supported reinforced concrete T-beams with multiple circular web openings to concentrated static and impact loading. Carbon fiber reinforced polymer (CFRP) was used for strengthening some of the beams with web openings. Five beams were exposed to static loading up to failure while the other beams were subjected to repeated impact loading until the shear crack width reached 0.3 mm (0.012 in.). The residual static strength of these beams was then determined. Test variables included the number of web openings and the height of weight drop during impact tests. Static loading test results indicated that unstrengthened beams with four and six openings have strength less than those without openings by 30% and 41%, respectively. However, strengthening using CFRP installed on beams web around openings resulted in an increase in the strength capacities ranging between 32% and 93%. Impact load data indicated that the beam with four openings did not show a significant increase in midspan deflections as compared with the specimens with no web openings. In comparison, the beam with six openings showed a 75% increase in the maximum midspan deflections compared with the beam with no web openings.

Fiber reinforced plastics (FRPs) have become a first choice for strengthening/repairing concrete members deficient in shear, flexure or torsion. However, oftentimes, the desired increase in capacity of FRP repaired/strengthened member is not achieved due to premature failures that occur at loads lower than the loads associated with failure of constituent materials (concrete, steel, FRP). Examples of premature failures in FRP retrofitted concrete applications include (1) plate-end debonding, (2) intermediate crack induced debonding (ICID), and (3) concrete cover separation (CCS). This paper present three-dimensional finite element (FE) models developed mainly to demonstrate the capability of FE models in predicting such failures, and to serve as reference for future FE studies concerning the behavior of RC members bonded to FRP reinforcement. Five RC beams, tested in previous experimental study by the authors, are modeled. The beams include a control beam; beam strengthened with spliced CFRP rod panel, beam strengthened with spliced CFRP rod panel, anchored at panel’s ends with CFRP wraps; beam strengthened with one (full-length) CFRP laminate, and beam strengthened with lap-spliced CFRP laminate system. Results, including load mid-span deflection response, strain profile along FRP length, and failure modes, showed that the presented FE models can replicate the experiments and predict the various premature failures oftentimes observed with FRP retrofitted concrete members.

FRP is customarily used to wrap concrete columns to increase their strength and strain capacities by providing extra confinement. Typically, steel hoops or spirals are used in constructed columns as mandated by codes. The behavior of retrofitted columns becomes thoroughly different because there are two systems with different mechanical response and interaction engaged in confinement. While most of the literature addressed concrete confined with FRP only, a limited number of studies and experimental cases accounted for both actions. This paper developed an axial stress-strain model which utilized geometric and mechanical properties of concrete, steel and FRP. The proposed work adopted Lam and Teng model for concrete confined with FRP, originally implemented in ACI 440.2R-17 guide, and calibrated its parameters against experimental curves. The proposed model correlates well with experimental cases that were collected from the literature.