Crack Load Research Articles

Short- and long-term performance of the novel additional aluminum alloy ribs anchored CFRP reinforced pretensioned PC beams

The anchorage shortage in FRP (fiber reinforced polymer) reinforced pretensioned prestressed concrete (PPC) elements has frequently led to the uncontrollable slippage. To provide a practical answer to this issue, an innovative additional aluminum alloy ribs (ARs) anchorage was developed. This study mainly investigated the effect of the ARs anchorage on the performance of the CFRP reinforced PPC beams subjected to flexural loading. Two kinds of loading types (i.e. short- and long-term loading) and two sustained loading levels (i.e. 40% and 75% of the short-term capacity) for the tested beams were included. The results indicated that ARs anchorage could shorten the transfer length and improve the short-term diagonal concrete cracking load in PPC beams by as much as about 20%. In addition, the ARs anchorage presence was capable of reducing the long-term slip by more than 2 times after the beams were loaded up to 120 days, and meanwhile delaying the diagonal concrete crack width increase by up to 70.9%-86.4%. Due to such merits, a less long-term prestressing loss was found and the long-term deflection of the beam was decreased by 50.8%–82.9%. More significantly, one of the unanchored PPC beam failed by complete bar slippage after being loaded for 146 days, whereas the ARs anchored beams have successfully sustained the 584-day loading and showed a convergent slip development. Finally, two calculation methods for the FRP reinforced beams were adopted to predict the long-term deflection of the tested beams, and the analytical and experimental results were compared and analyzed.

Global energy release rate of small penny-shaped cracks in hyperelastic materials under general stress conditions

With a finite element procedure on representative volume elements the relationship between the global energy release rate of small penny-shaped cracks within a widely extended hyperelastic continuum and general stress condition is investigated systematically. Based on the numerical results an empirical function is derived, which quantifies the relationship between this crack loading parameter and the surrounding stress state in terms of two continuum mechanical energy densities. It accounts for the sensitive, direction-independent crack loading in case of dilatational stress components as well as the influence of the crack orientation on the global energy release rate in the presence of distortional stress components. The derived empirical function is used to evaluate the material stress of a hyperelastic adhesive based on the crack propagation potential of small cracks that may exist within the adhesive layer, as exemplified by the poker-chip specimen and the bonded double cantilever beam specimen.

A set of electrically conducting collinear cracks between two dissimilar piezoelectric materials

The plane problem of multiple collinear cracks between two piezoelectric semi-infinite spaces is considered. The cracks can have arbitrary lengths and distances between each other and they are assumed to be electrically conductive. The materials are polarized in the orthogonal to the interface direction. In-plane combined tension-shear loading and the electric field parallel to the crack faces are prescribed at infinity. The Riemann-Hilbert problems of linear relationship are formulated and solved analytically by using the presentations of electro-mechanical quantities via sectionally-analytic functions. The arbitrary constants are found from the conditions at infinity and the system of linear algebraic equations which dimension is equal to the number of cracks. Stresses, electric field outside cracks as well as mechanical and electrical displacement jumps along the crack regions are found in the relatively simple analytical forms. Special attention was devoted to the energy release rate (ERR) determination. Due to analysis of asymptotic fields at the tips of single and multipleinterface cracks, the analytical presentations of the ERR for any crack tips are obtained. Numerical illustrations for several interface cracks are presented. The variations of stresses, electric field and the crack opening along the interface are demonstrated. The ERR are given for different crack tips, loading, crack locations and different physical aspects of the interaction effect are discussed. The particular cases of purely elastic and purely electrically conductive states are considered and good agreement with known results is demonstrated.

A Review on Flexural Behaviour of RC Beam with Nano-Silica

The partial replacement of cement with nanomaterials such as nano-silica(NS) particles in concrete improves its strength and other properties. In this study, the effect of NS as a partial replacement of cement for concrete mixes and concrete beams was examined. The studied response characteristics of reinforced concrete beams included compressive strength, failure mechanisms, load-carrying capacity, and load-deflection behavior. The results showed that compressive strength increased with an increase in NS content up to 2.0% replacement of cement weight. The rate of increase in compressive strength was no longer significant beyond 2.0% replacement, indeed there was a slight decrease in compressive strength for NS content of 3.0%. The effect of increased NS content on the flexural behavior of beams was also studied. Increased NS content led to increases in the first-cracking and ultimate loads and reductions in the deflection at cracking and ultimate load levels.

Evaluation of Mechanical Characteristics of High-Strength Reinforced Concrete Columns with Hexagonal Chicken Wire Mesh Under Cyclic Loading

Recently, new materials and methods have been implemented to improve the performance of reinforced concrete columns. This paper studies experimentally the behavior of reinforced high-strength columns, with additional internal confinement using hexagonal chicken wire mesh (HCWM) to enhance ductility, energy absorption, and ultimate strength and reduce the brittleness of traditional columns. Eight double-ended one-third-scale columns with different volumetric ratios of transverse rebar have been constructed and loaded under the uniform axial compression and lateral cyclic loads. Different volumetric ratios of transverse rebar were provided based on special, intermediate, and ordinary moment frames specifications of ACI 318–14 (named SD, ID, and OD, respectively). The specimens were confined by transverse rebars and HCWM and the results were compared with reference specimens with traditional transverse ties. Experimental findings demonstrated that HCWM specimens exhibited better performance compared to their control specimens concerning crack control efficiency, load capacity, ductility, energy dissipation, and failure modes. Implementation of HCWM increased the ultimate deformation, ductility, and energy absorption of OD specimens up to 21%, 50%, and 175%, respectively, compared to their control specimen. Confinement of the concrete columns by HCWM increased the ultimate strength of OD and ID specimens up to 15% and 22% under the cyclic load, but has a negligible effect on SD columns due to enough ratio of transverse and longitudinal rebars in SD specimens. As a result, confinement of specimens by HCWM could be regarded as a simple and effective method to improve the seismic characteristics of RC columns, particularly those members constructed with a minimal number of transverse rebars.

Structural Behavior of Reinforced Lightweight Concrete Slabs

This paper presents an exploration of choosing the optimum density for concrete that achieves the best structural performance for two-way slabs made of concrete with fine aggregate in different proportions less than the ratio used in ordinary concrete to produce different densities, by taking advantage of the idea of fine aggregate concrete which considers as light-weight concrete to achieve lighter concrete with higher structural endurance. The experimental program includes constructing and testing five slabs, four of them made of concrete with different fine aggregate radios 75%, 50%, 25%, and 0% to get different densities (2207, 1792, 1536, 1310 kg/m3) as well as another slab made of normal concrete used as a reference slab with a density of 2414 kg/m3. The outcomes reveal that decreasing the density of the slab from 2414 kg/m3 to 1310 kg/m3 by reduction fine aggregate in concrete from 100% to 0% respectively has more effect on the first crack load than that on the ultimate load of two-way slabs as the first crack load decreases with percentages 16.7%, 33.3%, 38.9%, and 61.1% the while the ultimate load decreases with percentages 7.3%, 21.9%, 46.3%, and 56.1%, respectively as compared to the reference (normal wight concrete slab). Also, decreasing the density of the slab made the cracks form and spread quickly and the slab failure tends towards the brittleness, and the cracks diffused and grew faster and wider.

Structural Behavior of Reinforced Concrete Beams Containing Pet Waste Particles as Sand Replacement

Abstract This paper examined the polyethylene terephthalate (PET) polymer waste effect that using as a partial replacement for fine aggregate on the R.C beams structural behavior. Six replacement percentages by weight were used in this study: 5 %, 7.5 %, 10 %, 12.5 %, 15 %, and 20 %. Seven concrete beam specimens with dimensions of 150 × 300 × 2300 mm were tested, in which one specimen for each PET replacement percentage was added to the reference specimen. four-point load setting were used to test all specimens via failure load, maximum deflection, energy absorption, stiffness, ductility index, flexural strain, first crack load, and crack pattern. Results showed that raising of PET percentage in the concrete beams leads to an increase in failure load, maximum deflection, ductility index, strain, and energy absorption compared with the reference beam in the ranges 0 – 4 %, 23.2 – 93.7 %, 12.13 – 93 %, 432 – 1139 %, and 51.8 – 275.4 %, whereas its causes a decrease in initial stiffness and secant stiffness in the ranges 5.8 – 38.44 % and 19.2 – 46.4 %. Moreover, crack investigations revealed that the load at which the first crack forms raise when the PET waste content increases.

Behaviour of Hybrid Fibre-Reinforced Ternary Blend Geopolymer Concrete Beam-Column Joints under Reverse Cyclic Loading.

Beam–column joints are extremely vulnerable to lateral and vertical loads in reinforced concrete (RC) structures. This insufficiency in joint performance can lead to the failure of the whole structure in the event of unforeseen seismic and wind loads. This experimental work was conducted to study the behaviour of ternary blend geopolymer concrete (TGPC) beam-column joints with the addition of hybrid fibres, viz., steel and polypropylene fibres, under reverse cyclic loads. Nine RC beam-column joints were prepared and tested under reverse cyclic loading to recreate the conditions during an earthquake. M55 grade TGPC was designed and used in this present study. The primary parameters studied in this experimental investigation were the volume fractions of steel fibres (0.5% and 1.0%) and polypropylene fibres, viz., 0.1 to 0.25%, with an increment of 0.05%. In this study, the properties of hybrid fibre-reinforced ternary blend geopolymer concrete (HTGPC) beam-column joints, such as their ductility, energy absorption capacity, initial crack load and peak load carrying capacity, were investigated. The test results imply that the hybridisation of fibres effectively enhances the joint performance of TGPC. Also, an effort was made to compare the shear strength of HTGPC beam-column connections with existing equations from the literature. As the available models did not match the actual test results, a method was performed to obtain the shear strength of HTGPC beam-column connections. The developed equation was found to compare convincingly with the experimental test results.

Punching shear strength of recycled aggregate-steel fibrous concrete slabs with and without strengthening

This paper presents an experimental study on the punching shear behavior of reinforced concrete flat slabs fabricated using recycled coarse aggregate (RCA) in addition to the presence of steel fibers strengthened by carbon fiber reinforced polymer (CFRP). The ratios of replacement natural coarse aggregate by RCA were (0, 35, 55, and 75%) and the volume fraction of the steel fiber used in this study was 1.2%. Two strengthening methods were used, namely, externally bonded reinforcement (EBR) and externally bonded reinforcement on groove (EBROG). 16 square slabs were cast with overall dimensions of 800 mm by 800 mm by 80 mm thickness. The slabs were designed to fail in punching shear only. All the slabs were simply supported on four edges and tested for punching via a vertical load applied through the square central column. The test results showed that the mechanical properties, ultimate loads, and first crack loads decreased with increasing proportion of RCA replacement, while the incorporation of steel fibers improved the compressive strength and ultimate loads by the ranges of 12%–17% and 16%–25%, respectively. Strengthened slabs lead to considerable improvements in the punching behavior of slabs, with an increase in punching load ranging from 22–30% compared to unstrengthened slabs when using the EBR technique, while the increase in the punching loads ranged between 40 and 55% when using EBROG strengthening technique. However, using half amount of CFRP with the EBROG method led to an increase in punching shear of 20–28%. This research indicates the particular improvement offered by the EBROG with regard to the punching shear capacity of fibrous recycled coarse aggregate concrete (RCAC) slabs compared to the EBR method. In addition, the mode of failure of reinforced concrete (RC) slabs changed from one of debonding failure to concrete cover separation when using the EBROG method.

Flexural Behavior of the Layered Beams Containing Reactive Powder Concrete and Self-Compacting Concrete

Reactive powder concrete (RPC) possesses superior structural and mechanical characteristics. Despite these excellent properties, the main drawback of RPC is that it is a very costly material. This study included an experimental program for studying the flexural behavior of hybrid beams containing RPC together with self-compacting concrete (SCC) in the same section. Five specimens with dimensions of 100 x 150 x 1000 mm were investigated. The first crack load, ultimate load, maximum deflection, load-deflection response, and crack pattern were investigated. The experimental program included testing five reinforced concrete beams with four-point loading. The specimens were cast as follows: full depth of self-compacting concrete; full depth of reactive powder concrete; half of the section depth of RPC (tension zone); quarter of the section depth of RPC (tension zone); and half of the section depth of RPC (compression zone). The experimental results of the hybrid beams showed that using RPC in the tension zone of the beam significantly improved the performance of the hybrid beams when compared with the SCC beam. The improvement rate increased with the RPC layer thickness in the tension zone. Using RPC in the compression zone together with SCC did not produce a significant improvement in the performance of the hybrid beams.

The Influence of Drop Panel's Dimensions on the Punching Shear Resistance in Ultra-High-Performance Fiber-Reinforced Concrete Flat Slabs

Ultra-high performance fiber reinforced concrete (UHPFRC) is a high-performance cementitious material with enhanced tension, compression, and toughness, strengths in the post crack region with high ductility, toughness, and durability. The companies prefer to use it to construct highly durable structures such as high-rise buildings, towers, and bridges. In addition, the thickness of the flat slab produced by UHPFRC might be thinner than the conventional concrete. One problem that has always been a concern in a flat slab is the punching shear failure since this failure is brittle and occurs suddenly without any previous notice. Besides, the position of the critical section for punching shear could be changed based on the thickness of the drop panel and the inclusion of fiber in the concrete. This paper highlights the effect of drop panels dimension on the punching shear resistance in UHPFRC flat slabs. The four two-way interior UHPFRC supported flat slab panels, consisting of one control flat slab without drop panels and three-flat slabs with different sizes of drop panels (10.5%,14.5%, and 19%) of the total area of slab drop panels, tested under punching load. Results indicated that the covered area of flat slabs by drop panel around 10.5% improved punching load up to %20 and 37% at the crack and ultimate loads. Furthermore, the test results show that the efficient covered area for resisting punching was 10.5% of the total area of the tested slab. Besides, the deflection values, strain in reinforcement and concrete, rotation at supports, and the inclination angles of cracks were improved due to the stiffness enhancement in the flat slabs.

Flexural Behaviour of Hybrid Fibre-Reinforced Ternary Blend Geopolymer Concrete Beams

Geopolymer concrete is one of the innovative eco-friendly materials that has gained the attention of many researchers in the sustainable development of the construction industry. The primary objective of this experimental investigation is to study the flexural behaviour of the ternary blend geopolymer concrete (TGPC) with various proportions of hybrid fibres. In this study, 27 reinforced concrete beams were cast with a TGPC grade of M55 and tested under monotonic loading conditions. The specimens were beams of length 1200 mm, depth of 150 mm, and width of 100 mm. Crimped steel (metallic) fibres and polypropylene (non-metallic) fibres were used in hybrid form to study the effect on the TGPC beams under flexure. The volume fractions of steel fibres were varied up to 1% with an increment of 0.5%, and polypropylene fibres varied from 0.1% to 0.25% with an increment of 0.05%. The test results were analysed based on the first crack load, ultimate load, load-deflection behaviour, energy absorption capacity, moment-curvature relationship, and ductility behaviour and compared with TGPC specimens without fibres. The experimental study reveals that the TGPC is one of the best alternatives for conventional cement concrete. The addition of hybrid fibres potentially improves the flexural properties of TGPC to a great extent. The test results showcased that the HTGPC with 1% steel and 0.1% polypropylene fibres exhibited better flexural properties than the other combinations of hybrid fibres considered in this study. Additionally, an effort was made to develop a model to estimate the flexural strength of TGPC with hybrid fibres, and the predicted values were found satisfactorily with the test results.

Short-term and long-term behavior of RC beams strengthened by galvanized steel mesh laminate

Steel reinforced polymers (SRP) are useful in a wide range of applications, including strengthening of existing reinforced concrete (RC) structures, due to their numerous advantages like high strength, low maintenance, light weight and low cost. As such, galvanized steel mesh (GSM) has emerged as an option in the strengthening of RC structures. Although numerous studies were performed on GSM strengthened RC beams, the durability of such strengthening systems is yet to be fully understood. This paper presents an experimental and numerical study to investigate the strengthening effect of GSM on RC beams as well as the time-depended behavior of RC beams with and without strengthening. Reinforced concrete beams without strengthening were used as control beams. For the strengthened beams, both high cord density galvanized steel mesh (HSM) and medium cord density galvanized steel mesh (MSM) were used after which the beams were exposed to Qatar atmospheric environment for different periods of time following 28 days of water curing. Finite element analyses using ABAQUS software were conducted to predict the mechanical behavior of the RC beams with and without strengthening. The results showed an improvement ranging from 46% ∼ 57% in the ultimate load of GSM strengthened beams, with a higher initial cracking load ranging from 3% ∼ 35% when compared to the unstrengthened beams. On the other hand, the time-dependent effect of the concrete has limited influence on the initial cracking load of both systems (before and after strengthening) while the ultimate load increased gradually with time due to the strength development of concrete. The results obtained from this study are useful in improving the design, construction, and maintenance of RC beams strengthened with GSM laminates.

Variables affecting unstable fracture load of cracked pipes under hydrogen environment

This paper presents an analytical equation for the reduction of the unstable fracture load for a cracked pipe due to hydrogen embrittlement. The proposed equation shows that the reduction of the unstable fracture load due to hydrogen embrittlement depends not only on the toughness reduction due to hydrogen embrittlement but also on plastic tensile properties and the degree of plastic yielding at fracture of a pipe without hydrogen embrittlement (quantified using the proximity parameter for plastic collapse). Note that the proximity parameter for plastic collapse is affected by the pipe and crack geometries, loading condition and fracture toughness before hydrogen embrittlement. Two case study results are presented using published material data. The first case considers stainless steel data to demonstrate the effect of the toughness reduction due to hydrogen exposure and the degree of plastic yielding at fracture on the reduction of the unstable fracture load for a cracked pipe under hydrogen embrittlement. The second case uses two sets of API 5L X42 and X70 pipeline steel data to illustrate the effect of plastic tensile properties.

Effect of Wire-Mesh Type on Strengthening Reinforced Concrete Beams

Structural strengthening is a method of application to raise the load-ability capacity of building structures to meet the building's need to carry additional and unexpected loads that were not accounted for in the main design. In this study, Ferro-cement was used for strengthening concrete beams. Three locally available wire mesh types were used with an ordinary cement mortar to strengthen reinforced concrete beams under flexural loading. The results show that using a Ferro-cement layer with wire mesh of 15 mm size square opening has the best effect on increasing reinforced concrete beams' bearing capacity and deflection more than when using the other two types of meshes. The first crack and failure load increases were 72 and 79%, respectively. In contrast, the deflection increased 70 and 51% at the first crack and failure load.

Use of rubberized engineered cementitious composite in strengthening flexural concrete beams

This study aimed to investigate the flexural behavior of reinforced concrete beams strengthened with high-performance rubberized engineered cementitious composite (RECC) at different cross-sectional positions (compression and tension zones). The RECC material was developed with different sizes of rubber particles, including 4.75 mm crumb rubber (CR) and 0.4 mm powder rubber (PR). The investigation tested conventional normal concrete (NC) and two full RECC beams with CR and PR as reference beams for comparison. A four-point bending test was conducted to evaluate the flexural strength, ductility, energy absorption, deformability, first cracking load, and cracking behavior of the strengthened beams compared to the reference beams. The study also compared the experimental results and their theoretical predictions calculated by design code equations and proposed model from the literature. The results revealed that using a RECC layer in the compression side exhibited a significantly higher deformability, cracking behavior, ductility, and energy absorption compared to the reference NC beam. Meanwhile, placing a RECC layer in the tension side showed lower ductility and energy absorption capacity compared to counterpart beams strengthened in the compression side, but still higher than the NC reference beam. The results also indicated that strengthening the beam in the compression side with a RECC layer developed with PR showed better enhancement in the energy absorption and ductility compared to a RECC layer developed with CR.

Experimental and numerical study on the cracking behavior and flexural strength of RC shallow beams with rectangular opening and varying length

In Ethiopia, the two way beam floor system gains popularity in building construction patterns where large column free space is mandatory, whose beam slenderness ratio is less than 15. The provision of mechanical and electrical line services in these beams is handled by a non-engineered manner of organizing elongated openings to enhance the regimented compact service network, due to the shortcoming of code. Hence, this paper deals with an experimental investigation on the cracking behavior, load–deflection behavior, and failure mode of beams with elongated openings whose slenderness ratio is less than 15 to formulate an engineered pattern. The experimental results are validated by performing numerical computations using finite element software. The specimens are tested under two point loading and the effect of opening under the varying length is studied in terms of first crack load, ultimate load, flexural strength, deflections, and failure load.

Research on low-temperature performance of steel slag/polyester fiber permeable asphalt mixture

In order to improve the low-temperature crack resistance of the permeable asphalt mixture, five steel slags with equal volumes of substitution rates (0%, 25%, 50%, 75%, 100%) were used to replace the limestone coarse aggregate above 2.36 mm. At the same time, six types of polyester fibers (0%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50% by the weight of the mixture) were selected to prepare permeable asphalt mixture samples. The ultrasonic non-destructive testing test, semi-circular bending (SCB) test and scanning electron microscope (SEM) test were carried out to study the cracking performance of steel slag/polyester fiber asphalt mixture at low temperature (0 °C, −10 °C, −20 °C). Ultrasonic non-destructive testing shows that by appropriately increasing the number of compactions (85 times), the aggregate embedding effect of G50X0.45 permeable asphalt mixture can be increased, and the compactness of the mixture can be improved. SCB test results suggest that the critical load for cracking of steel slag/polyester fiber permeable asphalt mixture first increased and then decreased with the decrease of temperature, reaching the maximum at −10 °C; At 50% steel slag replacement rate and 0.45% polyester fiber content, the ultimate tensile stress and ultimate tensile strain of the asphalt mixture were the largest, showing the optimal low-temperature crack resistance. The SEM test results indicate that adding steel slag enhances the embedding and squeezing effect between the internal aggregates of the mixture, the physical and chemical adsorption between the steel slag and the asphalt forms an asphalt orientation layer, which enhances the cohesion of the mixture. The incorporation of polyester fiber weaves a three-dimensional structure network inside the mixture, which firmly locks the coarse and fine aggregates together, greatly improves the density of the mixture, reduces the freeness of the asphalt, and thus improves low-temperature crack resistance of steel slag/polyester fiber asphalt mixture.

Structural behavior of hollow-core reinforced self-compacting concrete beams

This paper presents an experimental investigation on the structural performance of hollow-core reinforced self-compacting concrete beams and performs an optimization analysis to select the optimum hollow-core beam section, as well as perform a sustainability analysis. The experimental program includes constructing and testing five beams with different longitudinal hollow-core diameters created by using recycled plastic pipes, as well as a solid beam, used as a reference specimen. The results show that it can reduce the concrete from self-compacting concrete beams with percentages from 5.4 to 14.2 with a decrease in the first crack load from 9.1 to 22.7% and the ultimate strength from 2.3 to 10.5% respectively compared to the reference solid beam. The optimization analysis shows that the beam of 46 mm diameter hollow-core is the optimum selection in the concrete volume reduction of 11.1%, cracking load, and ultimate load reduction of 13.6% and 9.3% respectively among all the other beam specimens. While the sustainability analysis reveals that, using longitudinal voids of diameters from 32 to 52 mm leads to a decrease in the embodied energy with percentages from 5.4 to 14.2% and carbon dioxide emission with percentages from 5.4 to 14.1% respectively. Increasing the longitudinal void diameter makes hollow-core self-compacting concrete beams more ductile and exhibits large deflections before failure occurrences.Article HighlightsTests on hollow-core reinforced self-compacting concrete beams are conducted.Recycled plastic pipes are used to create hollow-core in the beams and to reduce ineffective concrete.Reducing ineffective concrete contributes to sustainability with maintaining a good ratio of beam strength.

Parameters affecting the behaviour of RC beams strengthened in shear and flexure with various FRP systems

An experimental investigation was carried out on rectangular RC beams strengthened with FRP in different strengthening forms in shear and flexure. The parameters examined in this study are as follows: The shear span to effective depth ratio (a/d), the number of FRP layers in shear, strengthening form (completely wrapping, U-wrapping, and side-bonding), FRP types (Glass or Carbon), and FRP strips width to spacing ratios (wf/sf). The experimental results showed that strengthening with FRP enhanced the load-carrying capacity, deflection capacity, initial stiffness, and ductility capacity with respect to the reference beams. Increasing the number of FRP layers in shear did not provide a proportional increase in the contribution of FRP to shear strength. The FRP types, FRP strips width to spacing ratios (wf/sf), the number of FRP layers in shear, a/d, and strengthening form affect the cracking patterns and loads of tested beams compared to reference beams. In addition, strengthening with FRP could change the failure modes of RC beams from brittle shear failure to more ductile flexural failure. It was also found that the equations used to calculate FRP contribution to shear strength (ACI 440.2R (2017), Fib-TG 9.3 (2001), Khalifa (2002), Triantafillou (1998), Bukhari (2010)) overestimated the FRP contribution and gave unconservative results, especially for U-wrapped and side bonded beams compared to the experimental results.