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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.

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...

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...

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...

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...

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...

The demand for sustainable concrete structures with longer service life and lower maintenance cost has been driving the use of glass fiber-reinforced polymer (GFRP) reinforcement in new concrete structures. The behavior of GFRP bars under seismic loading in reinforced concrete (RC) frame structures has not been widely investigated. Furthermore, the ability of FRP-RC frame structures to dissipate energy in seismic events is still questionable due to the elastic-linear behavior of the FRP reinforcement. Very few studies have been conducted on the seismic behavior of GFRP-RC exterior beam-column joints, and none studied the shear capacity of joints. Therefore, this study attempts to partially fill this gap by investigating the shear capacity of beam-column joints reinforced with GFRP bars and stirrups. Six full-scale exterior beam-column joint prototypes (T-shaped) were constructed and tested under simulated seismic load conditions. Test parameters in this study included the concrete strength and the...

Reinforced concrete beam-column joints are commonly used in structures such as parking garages and road overpasses, which might be exposed to extreme weathering conditions and the application of deicing salts. The use of the noncorrodible fiber-reinforced polymer (FRP) reinforcing bars in such structures is beneficial to overcome the steel-corrosion problems. However, FRP materials exhibit linear-elastic stress-strain characteristics up to failure, which raises concerns on their performance in beam-column joints in which energy dissipation, through plastic behavior, is required. The objective of this research project is to assess the seismic behavior of concrete beam-column joints reinforced with glass (G) FRP bars and stirrups. Five full-scale exterior T-shaped beam-column joint prototypes were constructed and tested under simulated seismic load conditions. The longitudinal and transversal reinforcement types and ratios are the main investigated parameters in this study. The experimental results showed that the GFRP-reinforced joints can successfully sustain a 4.0% drift ratio without any significant residual deformation. This indicates the feasibility of using GFRP bars and stirrups as reinforcement in the beam-column joints subjected to seismic-type loading. It was also concluded that, increasing the beam reinforcement ratio, while satisfying the strong column-weak beam concept, can enhance the ability of the joint to dissipate seismic energy.

Continuous concrete beams are structural elements commonly used in structures that might be exposed to extreme weather conditions and the application of deicing salts, such as bridge overpasses and parking garages. In such structures, reinforcing continuous concrete beams with the noncorrodible fiber-reinforced polymer (FRP) bars is beneficial to avoid steel corrosion. However, the linear-elastic behavior of FRP materials makes the ability of continuous beams to redistribute loads and moments questionable. A total of seven full-scale continuous concrete beams were tested to failure. Six beams were reinforced with glass fiber-reinforced polymer (GFRP) longitudinal bars, whereas one was reinforced with steel as control. The specimens have rectangular cross section of 200×300 mm and are continuous over two spans of 2,800 mm each. Both steel and GFRP stirrups were used as transverse reinforcement. The material, spacing, and amount of transverse reinforcement were the primary investigated parameters in this s...

In the last decade, noncorrodible fiber-reinforced polymer (FRP) reinforcing bars have been increasingly used as the main reinforcement for concrete structures in harsh environments. Also, owing to their lower cost compared with other types of FRP bars, glass-FRP (GFRP) bars are more attractive to the construction industry, especially for implementation in bridge deck slabs. In North America, bridge deck slabs are exposed to severe environmental conditions, such as freeze-thaw action, in addition to traffic fatigue loads. Although the bond strength of GFRP bars has been proved to be satisfactory, their durability performance under the dual effects of fatigue-type loading and freeze-thaw action is still not well understood. Few experimental test data are available on the bond characteristics of FRP bars in concrete elements under different loading and environmental conditions. This research investigates the individual and combined effects of freeze-thaw cycles along with sustained axial load and fatigue loading on the bond characteristics of GFRP bars embedded in concrete. An FRP-reinforced concrete specimen was developed to apply axial-tension fatigue or sustained loads to GFRP bars within a concrete environment. A total of thirty-six test specimens was constructed and tested. The test parameters included bar diameter, concrete cover thickness, loading scheme, and environmental conditioning. After conditioning, each specimen was sectioned into two halves for pullout testing. Test results showed that fatigue load cycles resulted in approximately 50% loss in the bond strength of sand-coated GFRP bars to concrete, while freeze-thaw cycles enhanced their bond to concrete by approximately 40%. Larger concrete covers were found more important in cases of larger bar sizes simultaneously subjected to fatigue load and freeze-thaw cycles.

Near-surface-mounted (NSM) reinforcement has become a well-known method for strengthening existing concrete structures. The bond between the NSM reinforcing bars and concrete is the key factor in the NSM technique. In the NSM technique, there are two bond interfaces: one between the NSM bar and the adhesive, and the other between the adhesive and the concrete. For this technique to perform efficiently, these two interfaces need to be investigated. On the other hand, concrete structures that require rehabilitation are often exposed to aggressive environments. Many of these environments are related to cold-climate conditions as can be found in Canada. Environmental factors including freeze/thaw action, exposure to deicing salts, and sustained low temperatures combine to attack the integrity of repaired structures. Consequently, repair materials for the Canadian infrastructure must be able to withstand these harsh conditions for prolonged periods of time. A total of 80 NSM-fiber-reinforced polymer (FRP) bars installed in C-shaped concrete specimens were tested in pull-out setup to failure. Sixty specimens were tested at normal room temperature, while the remaining 20 specimens were tested after conditioning in an environmentally controlled chamber for 200 freeze/thaw cycles. The dimensions of the specimens were designed, upon a preliminary phase of testing, to ensure that no transverse cracking would occur in the specimen before bond failure of the NSM bar. The results are presented in term of failure load, average bond stress, strains in FRP bar, end slip, and mode of failure. A bond-slip model was proposed for the used FRP bars.

Continuous concrete beams are commonly used elements in structures such as parking garages and overpasses, which might be exposed to extreme weather conditions and the application of deicing salts. The use of the fiber-reinforced polymers (FRP) bars having no expansive corrosion product in these types of structures has become a viable alternative to steel bars to overcome the steel-corrosion problems. However, the ability of FRP materials to redistribute loads and moments in continuous beams is questionable due to the linear-elastic behavior of such materials up to failure. This paper presents the experimental results of four reinforced concrete beams with rectangular cross section of 200×300 mm continuous over two spans of 2,800 mm each. The material and the amount of longitudinal reinforcement were the main investigated parameters in this study. Two beams were reinforced with glass FRP (GFRP) bars in to different configurations while one beam was reinforced with carbon FRP bars. A steel-reinforced conti...

This paper provides a comparison and evaluation of the current test methods used to determine the strength of fiber-reinforced polymer FRP bent bars/stirrups at the bend location bend strength. The available methods depend on applying tensile forces through the straight portion of the bent bar/stirrup and keeping the bend zone restrained to generate a stress perpendicular to the bend direction in addition to the stress in the longitudinal direction. This could be achieved through the ACI 440.3R-04 B.12 test method for U-shaped bare FRP bars. Another possible method is the ACI 440.3R-04 B.5 which evaluates the bend strength of FRP stirrups by embedding them in two concrete blocks, which are pushed apart until the rupture of the FRP bent bars. Both methods were employed in testing FRP stirrups and bent bars and the bend strength was compared. The test results showed that the ACI 440.3R-04 B.12 test method consistently underestimates the bend strength of FRP stirrups. On the other hand, B.5 test method is more reliable and representative to the actual state of stresses in real concrete structural elements.

This paper presents the results of an experimental study conducted on the pullout capacity of glass fiber reinforced polymer (GFRP) postinstalled adhesive anchors embedded in concrete. A total of 90 adhesive anchors were installed using sand-coated GFRP reinforcing bars and tested under monotonic tension loading in accordance with ASTM E-488-96 in 1996. The test parameters were: (1) the GFRP bar diameter (25.4, 15.9, and 6.4 mm ); (2) the embedment depth (5, 10, and 15 db where db =bar diameter); (3) the adhesive type (epoxy-based and cement-based adhesives); and (4) installation conditions (wet or partially submerged and dry holes). The tested GFRP adhesive anchors were installed in concrete slabs measuring 3,750 mm long, 1,750 mm wide, and 400 mm deep. The test specimens were kept outdoors for 7 months to be subjected to real environmental conditions including freeze-thaw cycles, wet and dry cycles, and temperature variations. The experimental results indicated the adequate performance of GFRP adhesive ...

A total of seven large-scale continuous concrete beams reinforced with glass fiber reinforced polymers (GFRP) bars and stirrups were constructed and tested to failure. One reference beam was reinforced with steel bars and stirrups and six beams were reinforced longitudinally and transversally with GFRP bars. Moreover, a three-dimensional (3D) finite element (FE) model was constructed to simulate the shear behavior of such beams. The beams had rectangular cross section of 200×300 mm and were continuous over two spans of 2,800 mm. The test variables include concrete strength and transverse reinforcement ratio. All test beams failed in shear near the interior support after significant moment redistribution. Also, the test results showed that no significant increase in the shear strength occurred when the shear reinforcement ratio increased by using a larger stirrup diameter. On the other hand, the FE models showed that increasing the transverse reinforcement ratio through decreasing the stirrup spac...

This paper presents the test results of five full-scale reinforced concrete (RC) interior slab–column connections. Each specimen consisted of a 2,800-mm square slab with a thickness of 200 and 300-mm square central column stubs. Four slabs were reinforced with glass fiber–reinforced polymer (GFRP) bars and one reference slab was reinforced with steel bars. The connections were subjected to eccentric load with a moment-to-shear ratio equal to 0.15 m. The test parameters included the type and ratio of the reinforcement and concrete compressive strength. Test results revealed that increasing the GFRP reinforcement ratio or the concrete strength increased the connection capacity and decreased the deformation of the tested slabs. Moreover, the GFRP-RC connection that has similar reinforcement rigidity to the steel-RC one showed comparable capacity and deflection at failure. Test results were compared with different available models and design provisions including the Canadian standard, the American gui...

This paper presents the results of an experimental study to investigate the role of each layer of reinforcement on the behavior of concrete bridge deck slabs reinforced with fiber-reinforced polymer (FRP) bars. Four full-scale concrete deck slabs of 3,000 mm length by 2,500 mm width and 200 mm depth were constructed and tested in the laboratory. One deck slab was reinforced with top and bottom mats of glass FRP bars. Two deck slabs had only a bottom reinforcement mat with different reinforcement ratios in the longitudinal direction, while the remaining deck slab was constructed with plain concrete without any reinforcement. The deck slabs were supported on two steel girders spaced at 2,000 mm center to center and were tested to failure under a central concentrated load. The three reinforced concrete slabs had very similar behavior and failed in punching shear mode at relatively high load levels, whereas the unreinforced slab behaved differently and failed at a very low load level. The experimental punchin...

This paper describes an experimental program conducted to develop new carbon fiber reinforced polymer (CFRP) stirrups as shear reinforcement for concrete members. The structural behavior of the CFRP stirrups was examined. To simulate the performance mechanism of stirrups in concrete beams, the CFRP stirrup was embedded in two concrete blocks and tested in tension by pushing the concrete blocks away from each other. A total of 12 specimens were constructed and tested to failure. The test variables were the tail length of the stirrup beyond the bent portion, the stirrup anchorage, the bar diameter, and the embedment length. In addition, two full-scale concrete beams reinforced with CFRP stirrups as shear reinforcement were constructed and tested to failure. Test results of the concrete blocks indicated that the strength capacity at the bend of the newly developed CFRP stirrups was adequate and fulfilled the design requirements of different codes and design guides. Further, the tail length was found to be no...

FRP composites have been widely used as internal reinforcement for concrete bridge deck slabs. However, experimental researches on the behavior of such FRP-reinforced elements in general have been limited, especially those on fatigue performance. This research is designed to investigate the fatigue behavior of concrete bridge deck slabs reinforced with GFRP bars. A total of six full-size deck slabs were constructed and tested under concentrated cyclic loading conditions. Different reinforcement types, ratios, and configurations were used. Also, different schemes of cyclic loading were applied till failure. Finite element modeling was used to investigate the effect of different parameters on the ultimate static capacity. The results showed the superior fatigue performance and longer fatigue life of concrete bridge deck slabs reinforced with GFRP composite bars compared to the steel reinforced ones.

As bridge deck slabs directly sustain repeated moving wheel loads, they are among the bridge elements most susceptible to fatigue failure. Recently, glass fiber-reinforced polymer (FRP) composites have been widely used as internal reinforcement for concrete bridge deck slabs because they are less expensive as compared to other kinds of FRPs (carbon and aramid). However, there is still a lack of information on the performance of FRP–reinforced concrete elements subjected to cyclic fatigue loading. This paper investigates fatigue behavior and fatigue life of concrete bridge deck slabs reinforced with glass FRP bars. A total of 5 full-scale deck slabs were constructed and tested under concentrated cyclic loading until failure. Different reinforcement types (steel and glass FRP), ratios, and configurations were used. Different schemes of cyclic loading (accelerated variable amplitude fatigue loading) were applied. Results are presented in terms of deflections, strains in concrete and FRP bars, and crack widths at various levels of cyclic loading. The results show the superior fatigue performance and longer fatigue life of concrete bridge deck slabs reinforced with glass FRP composite bars.

This paper reports the test results of 11 reinforced concrete beams strengthened with carbon fiber-reinforced polymer CFRP sheets and subjected to an aggressive environment. In this study, eight beams were cracked and repaired with CFRP sheets, while the remaining three beams were kept uncracked as a control. The beams were 150 mm wide by 250 mm deep by 2,400 mm long and lightly reinforced with a reinforcement ratio of 0.6%. Two types of carbon FRP products were considered: Sheets and strips. In terms of environmental exposure, three beams were kept at room temperature and eight beams were subjected up to 300 wetting and drying cycles with deicing chemicals 3% NaCl. Following the exposure, the beams were tested to failure in four-point bending. In addition, nonde- structive tests were performed to determine the corrosion rate, as well as destructive tests to determine chloride diffusion and reinforcing bar mass loss. Based on the findings of the study, the long-term effectiveness of the CFRP strengthened reinforced concrete in aggressive corrosive environments was established.

A finite element model (FEM) was constructed using specialized three-dimensional (3D) software to investigate the punching shear behavior of interior slab-column connections subjected to a moment-to-shear ratio of 0.15 m. The FEM was then verified against the experimental results of full-scale interior slab-column connections reinforced with glass fiber reinforcement polymer (GFRP) bars previously tested by the authors. The FEM results showed that the constructed model was able to predict the behavior of the slabs with reasonable accuracy. Afterward, the verified model was used to conduct a parametric study to investigate the effects of reinforcement ratio, perimeter-to-depth ratio, and column aspect ratio on the punching shear behavior of such connections. The test results showed that increasing the tested parameters enhanced the overall behavior of the connections in terms of decreasing deflections and reinforcement strain and increasing the ultimate capacity. In addition, the obtained punching shear stresses of the connections were compared to the predictions of the Canadian standard and the American guideline for FRP-reinforced concrete structures.

Recently, there has been a rapid increase in using noncorrosive fiber-reinforced polymers (FRP) reinforcing bars as alternative reinforcement for bridge deck slabs, especially those in harsh environments. A new two-span girder type bridge, Cookshire-Eaton Bridge (located in the municipality of Cookshire, Quebec, Canada), was constructed with a total length of 52.08 m over two equal spans. The deck was a 200-mm-thick concrete slab continuous over four spans of 2.70 m between girders with an overhang of 1.40 m on each side. One full span of the bridge was totally reinforced using glass fiber-reinforced polymer (GFRP) bars, while the other span was reinforced with galvanized steel bars. The bridge deck was well instrumented at critical locations for internal temperature and strain data collection using fiber optic sensors. The bridge was tested for service performance using calibrated truckloads as specified by the Canadian Highway Bridge Design Code. The construction procedure and field test results under actual service conditions revealed that GFRP rebar provides very competitive performance in comparison to steel.

This paper evaluates the shear strength of one-way concrete slabs reinforced with different types of fiber-reinforced polymer (FRP) bars. A total of eight full-size slabs were constructed and tested. The slabs were 3,100 mm long× 1,000 mm wide×200 mm deep . The test parameters were the type and size of FRP reinforcing bars and the reinforcement ratio. Five slabs were reinforced with glass FRP and three were reinforced with carbon FRP bars. The slabs were tested under four-point bending over a simply supported clear span of 2,500 mm and a shear span of 1,000 mm. All the test slabs failed in shear before reaching the design flexural capacity. The experimental shear strengths were compared with some theoretical predictions, including the JSCE recommendations, the CAN/CSA-S806-02 code, and the ACI 440.1R-03 design guidelines. The results indicated that the ACI 440.1R-03 design method for predicting the concrete shear strength of FRP slabs is very conservative. Better predictions were obtained by both the CAN/...

This article reports the test results of seven full-scale reinforced concrete slab-column edge connections strengthened against punching shear using different methods. In this study, three slabs contained openings in the vicinity of the column, and the other four were without openings. The dimensions of the slabs were 1,540X1,020X120 mm with square columns (250X250mm). The openings in the specimens were square (150X150 mm) with the sides parallel to the sides of the column. The slabs were reinforced with an average reinforcement ratio of 0.75 percent. Except for the two reference slabs, two different strengthening techniques were considered. Technique I applies externally bonded fiber reinforced polymer (FRP) flexible sheets on the slab around the column in two schemes with one or two layers of FRP sheets glued to the tension face or both tension and compression faces of the slab. Both glass and carbon FRP sheets were considered. Technique II applies externally bonded FRP sheets using either the first or second scheme combined with installing steel bolts through holes across the slab thickness around the column. Based on the test results, the authors conclude that the presence of FRP sheets and steel bolts substantially increased the punching capacity of the connections. Code design expressions were conservative in predicting the experimental results.

Because concrete bridge deck slabs are much longer in the traffic direction, they experience transverse early-age cracks due to volumetric instability and restraint. In the last decade, the use of the noncorrodible fiber-reinforced polymer (FRP) bars in concrete bridges has significantly increased. This paper presents the experimental results of four full-scale, cast-in-place glass FRP–reinforced concrete (GFRP-RC) deck slabs, subjected to early-age shrinkage. The slabs measured 2,500 mm long×765 mm wide×180 mm thick. The longitudinal reinforcement ratio (0.30, 0.50, 0.70, and 1.1%) was the main parameter investigated in this study. The test results were presented in terms of cracking pattern, width and spacing, strains in both GFRP bars, and concrete over a period of 90 days after casting. The experimental results were compared with provisions and predictions from a published analytical model. It was concluded that the published numbers can reliably provide a minimum reinforcement ratio for br...

This paper presents the results of a statistical analysis aimed to optimize a concrete mix design for hot climates. A full factorial experiment with 3 × 4 × 4 × 3 treatment combinations (432) samples) of 48 mixes at three levels of temperature was used. The influences of the water/cement ratio (0.4, 0.5, and 0.6), coarse aggregate/total aggregate ratio (0.55, 0.6, 0.65, and 0.7), total aggregate/cement ratio (3, 4, 5, and 6), and temperature (24, 38, and 52°C) on compressive strength were characterized and analyzed using polynomial regression. Mathematical polynomials were developed for concrete strength as a function of temperature and mix proportion. Based on the statistical analysis, recommendations are provided on the optimum concrete mix for different temperatures as well as the mix that is least sensitive to temperature variations.

This paper investigates the shear behavior of continuous concrete beams reinforced with glass fiber–reinforced polymer (GFRP) bars and stirrups. A total of six beams, with 200×300 mm rectangular cross section and continuous over two spans of 2,800 mm each, were constructed and tested. Three main variables, namely, concrete strength, longitudinal reinforcement ratio, and transverse shear-reinforcement ratio, were investigated. Two beams were without transverse reinforcement to evaluate the concrete contribution to the shear strength and four beams had GFRP stirrups to examine the minimum shear-reinforcement contribution to the shear strength. All test specimens were designed to satisfy an assumed 20% moment redistribution. It was observed that all test specimens failed in shear near the interior support after significant moment redistribution from hogging moment to sagging moment regions. In addition, the test results were compared with the predictions of the CSA-S806-12, CSA-S6-06, and ACI 440.1R-06.