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Although structures made of concrete reinforced with fiber-reinforced polymers (FRP) have shown promising performance under gravity loads, their performance under cyclic loading is still one of the main concerns. Although the linear nature of FRP reinforcement could be advantageous in terms of limiting the residual damage after an earthquake event, it lowers the energy dissipation of the structure, which can compromise its seismic performance. In this research, adding steel plates at selected locations in moment-resisting frames is proposed as a solution to improve seismic performance of FRP-reinforced concrete (FRP-RC) structures. Three full-scale cantilever beams, one steel-RC, one FRP-RC, and one FRP-RC with proposed steel plates, were constructed and tested under reversed cyclic loading. The results indicated that the proposed mechanism effectively improves the seismic performance of FRP-RC beams by increasing their initial stiffness and energy dissipation. Moreover, a computer simulation, using the moment–curvature determination process, was conducted to calculate bending moment capacity of FRP-RC beams with steel plates.

A three-dimensional non-linear finite-element model (FEM) was constructed using a commercial software (ATENA-Studio) to investigate the transverse load distribution behavior of adjacent precast prestressed concrete box-girder bridges. An innovative connection between box girders was used, where transverse post-tensioning was applied at the top flanges only eliminating the need for intermediate transverse diaphragms. The FEM was validated in terms of deflections, strains, cracking and ultimate loads against experimental results previously reported by the authors. The validated FEM was then used to perform a parametric study investigating the influence of adding concrete topping, load location, and bridge width on the transverse load distribution behavior of the newly developed connection. The results of the FEM demonstrated the efficiency of concrete topping in limiting mid-span deflections up to 25%. Additionally, the maximum live load moment distribution factors (LLMDFs) for different load locations and bridge widths were evaluated.

Integrity ties are necessary in hollow-core slab floors as connections to prevent floor displacements under lateral loads and maintain the overall structural integrity of buildings. In Eastern Canada, the integrity tie for hollow-core slabs on masonry walls usually consists of a 10M (no. 3), L-shaped steel bar that is hammered into the supporting wall and grouted to the slabs. However, current North American design codes do not offer sufficient provisions to determine the capacity or predict the mode of failure of these ties and connections. This paper introduces the results of testing nine full-scale reinforcing bar connection assemblies under monotonic in-plane forces (compression, tension, and shear) until failure. Test parameters in this study included direction and orientation of the in-plane loading, the bearing type of the hollow-core slabs, and the use of adhesive. Test results showed that connections with dry-fit bars tested under compression failed by bar yielding followed by masonry beam crushing. In addition, the mode of failure under tension forces was governed by the loss of bearing of the slabs due to bar pullout and cover spalling. Under shear forces, the connection failed by bar yielding. Finally, the connections with adhesive had a similar mode of failure compared to their counterparts with dry-fit bars, but these did not show bar pullout from the masonry beam, therefore demonstrating higher stiffness.

Recently, developing a nonferrous reinforcement system (corrosion-free system) using durable and ductile cement-based materials that incorporate discrete fibers has been a promising option for exposed concrete structures in cold regions or marine environments. Therefore, in this study, properties of a novel type of cementitious composite comprising nano-silica and a high dosage of slag were investigated. The hybrid (layered) composites assessed in this study were composed of two layers of different types of cementitious composites. Normal concrete (NC) was used in the top layer combined with a layer of fiber-reinforced cementitious composite (FRCC) reinforced with either the recently developed basalt fiber (BF) pellets (basalt fiber strands encapsulated by a polymeric resin or steel fibers (SF)) that were used at different dosages. The post-cracking behavior in terms of residual strength, residual index, and toughness are presented and discussed. The analysis of results showed the effectiveness of the BF pellets in enhancing the post-cracking behavior of specimens, as they behaved comparably to counterpart specimens comprising SF, which makes them a good candidate for infrastructural applications including rehabilitation such as new bridge girders or overlays.

In this study, the performance of basalt pellet–reinforced cementitious composites (BPRCC) was evaluated after exposure to harsh conditions. The exposure consisted of consecutive 300 freeze...

When reinforced concrete (RC) slabs are supported directly on columns, a combination of shear forces and unbalanced bending moments is transferred between the slab and the columns at slab–...

In this study, the bond behavior of sand-coated glass fiber-reinforced polymer (GFRP) bars embedded in a novel type of cementitious composite, containing nanosilica, slag, and reinforced w...

Four full-scale specimens were constructed and tested under reversal cyclic loading to study the seismic performance of interior GFRP-RC beam-column joints. The main test parameters were joint shear stress ratio and type of reinforcement (steel or GFRP). The performance of the specimens was evaluated in terms of hysteresis diagrams, mode of failure, strains in the reinforcement and energy dissipations. Test results indicated that the linear nature of GFRP materials resulted in lower residual damage in GFRP-RC beam-column joints compared to the corresponding steel-RC counterparts. Moreover, GFRP-RC joints withstood multiple cyclic loadings up to 8% drift ratio without exhibiting brittle failure.

The mechanical and physical properties of glass fiber-reinforced polymer (GFRP) reinforcement are different from steel, which requires independent code provisions for GFRP-reinforced concrete (RC) members. The currently available code provisions for GFRP-RC members still need more research evidence to be inclusive. For example, the available provisions for confinement reinforcement of FRP-RC columns do not consider the effects of column aspect ratio, which is not yet supported by any available research data. In this study, two full-scale spirally reinforced GFRP-RC circular columns were constructed and tested under concurrent seismic and axial loads. Both specimens had an aspect ratio (shear span-to-diameter ratio) of 7.0, while other two specimens with an aspect ratio of 5.0, from a previous stage of this study, were included for comparison purposes. For each aspect ratio, each specimen was loaded under one of two levels of axial load; 20 or 30% of the axial load capacity of the column section. All test specimens had a 35 MPa concrete compressive strength, 350-mm diameter, 85-mm spiral pitch and 1.2% longitudinal reinforcement ratio. The experimental results were analyzed in terms of hysteretic response, drift capacity and inelastic deformability hinge length. Based on the experimental results, it can be concluded that the aspect ratio affects the magnitude of secondary moments and inelastic deformability hinge length. In addition, the aspect ratio may affect drift capacity of GFRP-RC columns, depending on axial load level.

The experimental results for large-scale slender circular reinforced concrete (RC) columns are presented and discussed in this study. One reference column was reinforced with steel bars an...

Composite materials like glass fiber-reinforced polymer (GFRP) is becoming widely acceptable to be used as a reinforcing material due to its high ultimate tensile strength-to-weight ratio and excellent resistance to corrosion. However, the seismic behavior of GFRP-reinforced concrete columns has not been fully investigated yet. This paper presents the results of a numerical analysis of full-size GFRP-RC rectangular columns under cyclic loading. The simulated column depicts the lower part of a building column between the foundation and the point of contra-flexure at the mid-height of the column. GFRP reinforcement properties and concrete modeling based on fracture energy have been incorporated in the numerical model. Experimental validation has been used to examine the accuracy of the constructed finite element models (FEMs) using a commercially available software. The validated FEM was used to perform a parametric study, considering several concrete strength values and axial load levels, to study its influence on the performance of the GFRP-reinforced concrete columns under cyclic loading. It was concluded that the hysteretic dissipation capacity deteriorates under high axial load level due to severe softening of the concrete. The FE results showed a substantial improvement of the lateral load-carrying capacities by increasing concrete compressive strength.

In this study, a new transverse post-tensioning (TPT) technique for box girder bridges is investigated, where TPT is applied at the top flange of the girder resulting in eliminating the in...

Columns in earthquake-resistant reinforced concrete (RC) structures need to be adequately confined to provide satisfactory levels of stability and deformability. In circular RC columns, co...

A series of finite-element analyses for slab­–column edge connections reinforced with fiber-reinforced polymer (FRP) reinforcement and subjected to reversed-cyclic lateral load is conducte...

Several empirical models have been introduced during the last two decades to estimate the punching capacity of two-way slabs reinforced with fiber-reinforced polymer (FRP) reinforcement. I...

This paper presents test results of seven large-scale circular concrete columns reinforced with either steel or glass fiber-reinforced polymer (GFRP) reinforcement. The columns measured 35...

In regions of high seismic activity, flat plate systems can be used as gravity force resisting systems, where special moment frames are provided as seismic force resisting systems. Neverthe...

In this study, seven concrete deep beams reinforced with glass fiber reinforced polymer (GFRP) headed-end bars were constructed and tested to failure. The beams had a rectangular section of 250 mm in width and 590 mm in depth with overall span of 1,390 mm and were tested under three-point bending loading. The main test variables were the longitudinal reinforcement ratio and the incorporation of fiber-reinforced cementitious composite material in the tie zone. The arch action mechanism developed in all specimens as substantiated by the measured strains along the tie length. In addition, analysis of test results showed that the incorporation of basalt fiber pellets or steel fibers in the tie zone of the beam improved the behavior including the ductility and the load carrying capacity. It was also found out that the provisions for strut-and-tie model in the Canadian codes for FRP-RC structures and the American code for steel-RC structures yielded reasonable predictions to the load capacity of deep beams.

This paper investigates the behavior of glass fiber reinforced polymer (GFRP)-reinforced concrete (RC) continuous beams subjected to unsymmetrical loading conditions. A total of six large-scale RC continuous beams were constructed and tested to failure. Three different loading cases were considered, (I) loading both spans equally, (II) loading both spans maintaining a load ratio of 1.5 and (III) loading one span only. The effects of reinforcing material type, assumed percentage of moment redistribution and serviceability requirements on the performance of the test beams were investigated. Also, a comparison between the experimental deflection and that predicted by available models, using effective moment of inertia approach, is presented. Test results revealed that, beams tested under unsymmetrical loading case II showed less crack widths, strains and deflections in the higher load span compared to those in the less load span or those symmetrically loaded. Moreover, the unsymmetrical loading conditions adversely affected the moment redistribution.

In this study, the behavior of six full-scale lap-spliced glass fiber-reinforced polymer reinforced concrete rectangular columns is presented. The columns were tested under simultaneous axial and quasi-static cyclic reversed loads. The experimental program was designed to determine the adequate splice length in such columns as well as the effect of different axial load levels on their performance. In addition, the effect of using steel fiber reinforced concrete (SFRC) on the behavior of columns with inadequate splice length is investigated. Test results showed that a splice length of 60 times the diameter of the longitudinal bar is adequate to transfer the full bond forces along the splice length and were able to maintain the lateral load carrying capacity when subjected to higher levels of axial loads and drift ratios. Furthermore, the use of SFRC in columns with inadequate splice increased the peak lateral strength and the energy dissipation of the specimens.

The seismic behavior of reinforced concrete (RC) circular columns rehabilitated with sprayed-glass fiber–reinforced polymer (GFRP) composites was investigated in this study. Six large-scale...

Although the seismic behavior of moment-resisting frames (MRFs) reinforced with conventional steel has been extensively studied, the performance of MRFs that are reinforced with alternative...

Concrete slabs, beams, and columns reinforced with glass fiber-reinforced polymer (GFRP) reinforcement have shown considerable deformability under monotonic loading; however, they have not ...

Four full-scale specimens were constructed and tested under reversal cyclic loading to study the seismic behavior of exterior glass fiber-reinforced polymer (GFRP)-reinforced concrete (RC) ...

This paper presents the experimental results of seven full-scale glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) slab–column edge connections. The dimensions of the slabs wer...

The shear behaviour of continuous concrete beams reinforced with glass fiber reinforced polymer (GFRP) bars without shear reinforcement has not been studied yet. However, the current codes and guidelines for FRP-reinforced concrete (RC) structures provide shear provisions that are applicable to both simple and continuous members. These provisions are based on test results of simple beams that do not account for the continuity of indeterminate structures. In this paper, the test results of large-scale GFRP-RC continuous beams without transverse reinforcement are presented. The test variables are the type and ratio of longitudinal reinforcement, and concrete strength aiming to evaluate the shear strength of such beams. The test results showed that moment and shear redistribution occurred. Also, the shear capacity of GFRP-RC continuous beams increased as both the longitudinal reinforcement and the concrete strength increased. Moreover, it was found that the continuity affected the concrete contribution to th...

Most of codes and guidelines for glass fiber reinforced polymers (GFRP) - Reinforced Concrete (RC) are based on modifying corresponding formulas, originally developed for steel bars, taking into account the differences in properties and behavior between FRP and steel. The main objective of this research is to investigate the effect of cyclic environments on early-age cracking of GFRP-RC bridge deck slabs experimentally. Two full-scale (measuring 2500-mm long × 765-mm wide × 180-mm thick) cast-in-place slabs reinforced with similar amounts of reinforcement ratio of 0.7% with GFRP and steel bars, respectively, were tested in adiabatic laboratory conditions as control specimens. In comparison, two other GFRP-RC deck slabs were tested under freezing–thawing and wetting–drying conditions. The test results are presented in terms of materials degradation, cracking pattern, crack width, and spacing, and strains in reinforcement and concrete. Test results indicate that the minimum reinforcement ratio (0.7%) recommended by the Canadian Highway Bridge Design Code 2006 (CHBDC 2006) for bridge deck slabs reinforced with GFRP bars satisfied the serviceability requirements after being subjected to the simulated cyclic exposures.

This paper presents the development of nanomodified fiber-reinforced cementitious composite (FRCC) mixtures. A total of seven mixtures were prepared using general use cement and a constant ...

This paper presents the experimental results of five full-scale glass fiber–reinforced polymer (GFRP) reinforced concrete (RC) columns with lap splices under axial and cyclic-reversed loads...

Three full-scale reinforced-concrete (RC) slab-column edge connections were constructed and tested to failure under a combination of gravity load and uniaxial reversed-cyclic lateral load. The main test parameters were the flexural reinforcement type [steel or glass fiber-reinforced polymer (GFRP)] and flexural reinforcement ratio [0.7 or 1.4%]. The performance of the connections was evaluated in terms of mode of failure, hysteretic response, stiffness, energy dissipation and strains in the reinforcement. It was demonstrated that GFRP-RC connections are able to safely achieve or exceed the minimum 1.50% drift capacity before punching failure with adequate deformability. The low modulus of elasticity and high tensile strength of GFRP bars allowed GFRP-RC connections to experience comparable reinforcement strains to those in the steel-RC counterpart. In addition, the linear nature of GFRP reinforcement resulted in lower stiffness degradation and lower residual damage in GFRP-RC connections compared to the steel-RC connection.

Flexural strengthening of reinforced concrete using near-surface mounted (NSM) fiber-reinforced polymer (FRP) composites is a widely studied topic, and a promising technology. However, overlooked applications such as prestressed concrete and one-way slabs require further experimental investigation and theoretical refinement in order to develop comprehensive design guidelines. This paper investigates the behavior of prestressed hollow-core slabs strengthened in flexure with NSM carbon FRP strip reinforcement. Seven full-scale simply supported slab specimens were tested to failure under two-point monotonic load configuration. Experimental variables included two different internal prestressing reinforcement ratios, and three different NSM strengthening reinforcement ratios. This paper examines cracking behavior and modes of failure, load-strain relationships, deflections, and strengthened capacities. Also, a comparison between experimental results and theoretical predictions by relevant Canadian and ...

This paper presents test results of six full-scale glass fiber-reinforced polymer (GFRP) reinforced concrete slab–column edge connections. The test connections included two series with three connections each. The connections of Series 1 investigated the effect of a new type of GFRP shear reinforcement on the punching shear behavior of slab-column edge connections, while those of Series 2 investigated the effect of moment-to-shear ratio. For Series 1, one connection did not have shear reinforcement, while the other two connections had ribbed-deformed GFRP shear studs with headed ends at different radial spacing (120 and 80 mm). For Series 2, three different moment-to-shear ratios were applied to the connections (0.2, 0.4, and 0.6 m). The typical dimensions of the slabs were 2,800×1,550×200 mm with a 300-mm square column extending above and below the slab. The headed ends of the studs provided adequate anchorage, which allowed the studs to control the propagation of shear cracks and to increase the...

Six full-scale reinforced-concrete (RC) interior slab-column connections of glass fiber–reinforced polymer (GFRP) were constructed and tested to failure. The specimen consisted of a square slab with a 2,800-mm side length and a 200-mm thickness in addition to a 300-mm-square column stub extended for 1,000 mm above and below the slab. The test specimens were subjected to vertical shear forces and unbalanced moments. The test variables included the moment-to-shear ratio, GFRP double-headed shear studs ratio, and the type of GFRP bar surface texture (ribbed or sand-coated). The test results revealed that increasing the moment-to-shear ratio reduced the vertical shear capacity and increased the deflections and the strains at failure. Moreover, the presence of the GFRP shear studs enhanced the slab capacity but was not able to change the punching shear mode of failure. Furthermore, the used two types of GFRP bars showed comparable behavior. The results were compared with the predictions of the availabl...

This paper presents an assessment of the seismic performance of concrete columns internally reinforced with glass-fiber-reinforced polymers (GFRP) bars. Eight full-scale column prototypes with 1,650-mm shear span and 350-mm square cross-section were constructed and tested under combined lateral cyclic quasi-static and constant axial loading. The test specimens represent the lower portion of first-story columns between the footing and the contra-flexure point. The test parameters included longitudinal reinforcement type and ratio, level of axial load, and stirrup spacing. Test results showed that the drift capacity of GFRP-reinforced concrete (RC) rectangular columns at failure ranged between 8.5 and 12.5%, which exceeds the limitations of North American building codes. This indicates that the deformability of GFRP-RC column prototypes successfully replaced the ductility in steel–RC columns in dissipating the seismic energy in the presence of constant axial load. Furthermore, there was insignifican...

Precast, prestressed, hollow-core (HC) slabs are extensively used in many structures such as parking garages, commercial and industrial buildings. It is common for such structures to undergo changes while still in service, which may result in a reduction of their strength. One of these changes is to add in-situ openings at different locations along the slab to accommodate services such as intake/exhaust ducts or utility conduits. Near surface mounted (NSM) strengthening technique has proved to be an adequate technique that can be employed to restore or enhance the performance of the original structure. In this paper, the effect of openings and the efficiency of using NSM carbon fiber reinforced polymer (CFRP) strips as strengthening technique are investigated. A total of three full-scale prestressed HC slabs were tested; one without opening, one with an opening in the pure flexural zone and one with strengthened opening. Test results showed the presence of opening along the flexure span had a significant adverse effect on the post-cracking flexural stiffness, cracking load and the ultimate capacity of the slab. However, strengthening the opening with two strips of NSM-CFRP effectively enhanced the post-cracking stiffness, increased the ductility of the member and restored the flexural strength deficit incurred as a result of cutting the opening, and provided a net increase in flexural capacity.