FRP Layers Research Articles

THEORETICAL ASPECTS OF AVOIDING DELAMINATION OF COMPOSITE MATERIALS DURING STRENGTHENING OF REINFORCED CONCRETE STRUCTURES

The scientific work is devoted to the improvement of the calculation methodology of reinforced concrete elements, using verification of the FRP delamination prevention, during structures strengthening with a system of composite materials (SCM) from various fibers types. During strengthening of reinforced concrete elements with composite material systems, the role of adhesion between concrete and FRP is of great importance due to the fragility of the failure mechanism due to delamination (loss of adhesion). The adhesion strength is generally much higher than the tensile strength of the concrete, so delamination always starts in concrete itself with the separation of FRP layer of different thickness. According to the load-bearing capacity requirements, such a failure mechanism should not precede the failure of the strengthened element during bending or shear. To solve the problem of possible strengthening delamination of composite materials systems, it is necessary to consider different failure modes of FRP. Due to imperfection of domestic building codes, a detailed analysis of the solution to the problem of FRP delamination was carried out in accordance with the recommendations of a number of foreign regulatory documents (ACI, CNR, FIB). The main failure modes, with subsequent initiation of delamination of FRP material from concrete base, are systematized, namely: FRP delamination due to surface irregularities, separation of FRP due to shear cracks, longitudinal shear stresses in the yield zone, excessive deformations in FRP material (FRP rupture), longitudinal shear stresses near the FRP edges, failure in anchoring (fixing) zone of FRP material. Six criterions are proposed that need to be verified during design of structures strengthening systems with FRP materials. During formulation of specified criterions, the main theoretical aspects necessary for application in structural calculations of the studied connection are given. The results of research can be used in future during the design of structures joints strengthening with systems of composite materials based on carbon fibers, glass, aramid. Keywords: system of composite materials, external reinforcement, FRP strengthening, reinforced concrete, failure mode, calculation, delamination.

Seismic behaviour of shear critical square RC columns strengthened by large rupture strain FRP

This paper presents an experimental study on the seismic behaviour of shear critical square columns strengthened by large rupture strain (LRS) FRP under reversed cyclic lateral load together with constant axial load. The experimental program included 2 control columns, 6 LRS FRP-strengthened columns, and 2 CFRP-strengthened columns. The tested specimens’ failure modes, hysteretic responses, ductility, and cumulative energy dissipation were carefully analyzed. The influences of axial load ratio, FRP layers, and FRP type on the seismic performance of these columns were investigated. Compared with the control column, the ductility ratio and energy dissipation of the column wrapped by 3-layer LRS FRP at a low axial load ratio were raised by 491.7 % and 6498.3 %, respectively. The advantage of LRS FRP over CFRP in seismic retrofitting for shear critical RC columns was demonstrated through comparative analysis for the first time. Although the tensile stiffness of 1-layer PET FRP is much smaller than 1-layer CFRP, the ductility ratio and cumulative energy dissipation of the 1-layer PET FRP-strengthened column under a low axial load ratio were still slightly larger than that of the column wrapped by 1-layer CFRP. The CFRP-strengthened column under a high axial load ratio showed sudden explosive failure, while the LRS FRP-strengthened columns exhibited progressive failure. In addition, the axial flexure shear interaction (ASFI) method considering buckling of longitudinal reinforcement in FRP-confined concrete was developed and verified by comparing test results and predicted envelope curves.

Axial compressive behavior of green sustainable Water Hyacinth & Bio-Resin (WHBR) FRP composites-confined circular concrete

This study examines the behavior of circular concretes externally confined by green sustainable WHBR FRP containing water hyacinth fiber ropes and bio-resin. This study principally purposes to discover the axial stress-strain relationship behavior of WHBR FRP-confined circular concrete. A total of 10 circular concretes with a dimension of 150×300 mm were cast, strengthened with one to four layers of WHBR FRP, and tested under compression. The stress and the deformability of WHBR FRP-confined circular concretes were observed to be increased along with the addition of WHBR FRP layers. The accurateness of existing ultimate stress and strain models of natural FRP-confined circular concrete was evaluated using the test results. Indicating the need for the newly developed models to precisely predict the ultimate stress and strain values of WHBR FRP-confined circular concrete, newly developed models were developed to be precise in estimating the ultimate stress and strain of WHBR FRP-confined circular concrete. Keywords concrete, confinement, disaster risk reduction, stress-strain, water hyacinth fiber.

A coupled XFEM fatigue modelling of crack growth, delamination and bridging in FRP strengthened metallic plates

This paper proposes an extended finite element method (XFEM) modelling approach coupled with cyclic damage mechanics criteria to simulate the fatigue crack growth (FCG), progressive delamination, and bridging in metal-fibre reinforced polymer (FRP) composites. The FCG in the metal is described using linear elastic fracture mechanics. The cycle-by-cycle degradation of the adhesive layer, progressive damage in the FRP layers, and metal-FRP interface delamination are modelled using the damage mechanics criteria. The proposed XFEM model successfully simulates the fatigue behaviour of FRP-strengthened metallic plates. The FCG rates, crack trajectories, fatigue lives, and failure modes satisfactorily agree with the corresponding experimental data.

Exploiting fiber control for delayed failure in 3D printed fiber reinforced polymer composites

3D printing technology has shown capabilities in producing radical shapes with unique infill patterns and configurations to enhance fiber reinforced polymer composites. The ability to use 3D printing technology to inherently transform FRP failure and post-peak behavior is an unexplored area that can provide a new class of FRP with improved failure behavior. In this study, four designs are developed with combinatorically angled fiber reinforced layers and manufactured using 3D printing technology that demonstrated a ductility up to 29%. The designs enable a gradual load transfer mechanism between different FRP layers demonstrating characteristic load drops and up to 8% strain at failure. Damage in combinatorically angled Glass Fiber Reinforced Polymers (GFRP) composite layers were observed to be mostly sequential compared with the abrupt broom-like failure in high strength FRP composite. 3D printed GFRP composite with Design 4 showed a yield-like plateau leading to a failure strain of 4.2% after reaching its ultimate strength of 260 MPa which is comparable to Grade B steel. The response of a 3D printed high strength GFRP composites was compared with high strength glass FRP composites manufactured using conventional methods. This comparison showed that increase in fiber volume fraction of 3D printer filament can improve mechanical response of resulting composites. This work demonstrates a pathway to manufacture the next generation of structural FRP composite systems with enhanced ductility and inherent mechanism for energy dissipation.

Finite element and theoretical investigations on PVC–CFRP confined concrete columns under axial compression

This article examines the performance of Carbon Fibre Reinforced Polymer (CFRP) on Concrete Filled with Polymer Vinyl Chloride Tube (CFPT) columns under axial compression. Firstly, 44 CFPT specimens from the literature were analyzed using ABAQUS software to understand the compressive behavior of specimens under applied displacement. Secondly, 268 CFPT specimens are simulated to understand the influence of CFRP on these control specimens with a varying number of FRP layers and wrapping depth. Other variables such as the unconfined concrete strength, the thickness of the PVC tube, and the size and slenderness ratio of the columns were also studied. Studies are extended to confinement damage plasticity model analysis of CFRP-CFPT (CCFPT) columns. Relationships between the load-carrying capacity of CCFPT columns and the CFRP properties were developed. The effect of these parameters on the CFPT leads to the development of analytical models. It is an advantage to applying a such new type of composite columns in various applications.

Finite element analysis of the effect of type, number, and installation angle of FRP sheets on improving the flexural strength of concrete beams

Using FRP material to strengthen concrete beams is one of the best methods to prevent cracks propagation in the tensile zone. In this article, a concrete beam is modeled using the finite element software Abaqus. In order to investigate the effects of type, number, and installation angle of FRPs, a total number of 25 numerical models are considered. In these models, 3 types of covers made of GFRP, CFRP, and AFRP materials, including 6 and 12 sheets, are used at the installation angles of 30, 45, 60, and 90 degrees. Also, at the bottom of the beam in all the models, FRP layers are used to prevent the growth of cracks. After applying a constant load of 60 kN on all models, the stresses produced in the beam together with displacement at the middle of the beam, are investigated. The results showed that with an equal number of sheets and equal distance of installed sheets, the effect of FRP sheets on reducing displacement is greater at an installation angle of 45 degrees compared to that of a 60-degree angle. Also, this effect is greater at an installation angle of 60-degree angle compared to that of a 90-degree angle. Furthermore, by the addition of plates, the maximum lateral strain at the middle of the beam span is reduced up to 12.5 %. Also, CFRP material had a better performance compared to the two other types of fibers. The addition of prestressed FRP sheets to the specimens increases their strength. The load increase continues to the point wherein the beam fails due to the crushing of the compressive concrete. Adding the prestressed FRP sheets to the specimens increases the strength against the ultimate load from 5.4 % to 26.4 %, compared to the beam, which has internal confinement by the inner rebars.

Axial behavior of basalt FRP-confined reinforced concrete columns with square sections of different corner radii

Axial compressive tests were conducted on fourteen BFRP-confined square reinforced concrete (RC) columns, involving variations of the corner radius and FRP layers. The test results demonstrate thatthe Basalt-FRP confinement leads to strength improvement, such as 109% gain at a corner radius ratio of 0.6, and also improves the ductility of the RC column. The stress–strain response has a bilinear type, and the difference in confinement level is mainly reflected in the inelastic range. Furthermore, the observation of the distribution of hoop strain values shows that the confinement pressure uniformity increases with thecornerradius. Finally, a prediction equation for the strain efficiency factor is proposed to improve the accuracy of existing square section strength models. A modified strength model of Wu and Zhou shows good agreement with the experimental results.

The Effect of GFRP Wrapping on Lateral Performance of Double Shear Lap Joints in Cross-Laminated Timber as a Part of Timber Bridges

Timber elements, such as timber bridges, are exposed to heavy loads. Therefore, reinforcement might be useful. Due to a lack of wood supplies, poplar, a fast-growing tree, could be used to construct CLT (cross-laminated timber). The low density of fast-growing wood species directly impacts the mechanical properties of CLT. Therefore, in this study, a CLT panel was reinforced with GFRP (glass-fiber-reinforced polymer), and the lateral resistance of double shear lap joints in reinforced CLTs with 0-90-0° arrangements in two strength directions was investigated. Lag screws (Ø = 8 mm) at the end distances of 1 and 3 cm were employed for making the lateral test specimens. First, the effect of the number of GFRP layers on lateral resistance of the joints was investigated. The results revealed that, as the number of GFRP layers changed from one to three, the lateral resistance increased by 45.47%, and then, by four layers, it decreased by 1.3%. Since the joints with three layers of FRP had the highest strength, the effects of the end distance and the CLT panel strength directions on the lateral performance of the reinforced and non-reinforced specimens were investigated. The results indicated that the lateral resistance of reinforced CLTs with GFRP was about 26.5% more than the unreinforced ones. Moreover, CLTs in the major strength direction showed 4.2% more lateral resistance than those in the minor strength direction. Moreover, lag screws at the end distance of 3 cm had 60% more lateral resistance than those at the end distance of 1 cm. In terms of failure modes, bearing, shear, and net-tension modes were observed in the CLTs, while Is, IIIs, and IV modes were observed in the lag screws.

Numerical analysis of circular tubed high-strength concrete columns with embedded steel tubes under axial compression

This paper presents an in-depth investigation into the compressive behavior of the circular tubed high-strength concrete with embedded steel tubes (THSC-ST) columns using a finite element (FE) approach. The composite action of the columns is comprehensively explored. It can be detected from the numerical results that the confinement provided by the external steel tube in the THSC-ST column is significantly enhanced since the external steel tube does not carry the axial load directly. Besides, increasing the diameter of the internal steel tube can effectively improve the axial stress of confined concrete. Moreover, more effective confining stress of the external tube is observed after wrapping FRP jackets, leading to stiffer the post-peak behaviors for the core and sandwich concrete simultaneously. An extensive parametric analysis is also performed based on the validated FE model to explore the effects of the internal steel tube location, the number of FRP layers, the thickness and yield strength of the steel tube, and concrete compressive strength on the structural behaviors of the THSC-ST columns. Finally, a new formula is proposed to estimate the axial load capacity of the THSC-ST columns and high predicted accuracy is found by the comparisons between the theoretical and experimental results.

Compressive Behavior of Predamaged Concrete Cylinders Repaired with Jute and Basalt FRP Composites: A Comparative Study

Natural fibers have become a research hotspot in composite materials recently. This study investigated the axial compressive behavior of predamaged concrete repaired by jute fiber–reinforced polymer (JFRP) composites. Basalt FRP (BFRP) was also utilized to repair the predamaged concrete for comparison. Thirty FRP-jacketed concrete cylinders with a diameter of 150 mm and a height of 300 mm were designed and fabricated. Plain concrete cylinders were axially preloaded to three predamage levels, then repaired by JFRP and BFRP composites, and reloaded to evaluate the compressive behavior after repair. The results showed that the predamage of concrete had a noticeable adverse effect on the compressive behavior of JFRP- and BFRP-repaired concrete. Compared with the JFRP-jacketed intact concrete, the compressive strength and initial elastic modulus of the JFRP-repaired predamaged concrete decreased by 6%–18% and 16%–54%, respectively. However, the compressive strength and ultimate strain of the predamaged concrete were still improved by 5%–41% and 82%–291% after JFRP repair, respectively, when compared with those of the plain concrete. On the contrary, the ultimate axial strain and lateral strain capacities of JFRP- and BFRP-repaired concrete were insignificantly affected by the concrete predamage. Under similar confinement ratios, the compressive strengths of JFRP- and BFRP-jacketed intact concrete were close to each other, whereas the axial strain–lateral strain relationship and the variations of the Poisson’s ratios were highly dependent on the FRP types and the number of FRP layers. Based on the test results and data collected from the open literature, an ultimate strength model, an ultimate axial strain model, and a stress–strain relationship model were newly developed for JFRP-repaired predamaged concrete.

Experimental investigation on the compressive behaviour of FRP-confined rectangular concrete columns

This paper presents a comprehensive experimental study on the behaviour of FRP-confined concrete in square and rectangular columns and focuses on some issues that might be addressed with a view to improving the predictive models. For this purpose, 31 prismatic concrete specimens with a height of 600 mm and low- and medium-strength concrete (20–35 MPa) were tested under centred compression. The parameters studied were the aspect ratio between the sides of the section (1, 1.5 and 2), the radius of curvature of the corners (20, 25 and 30 mm) and the number of carbon FRP layers applied. The experimental results included stress–strain curves of specimens and detailed information about the confined concrete strength and the axial and lateral strain achieved on the FRP jacket during the tests. The stress–strain response and ultimate condition are analysed, showing that FRP jacketing is an efficient technique for increasing the strength and strain capacity, but that confinement efficiency decreases as the aspect ratio of the section increases. In spite of such decrease, significant strength improvement was achieved for low-strength concrete in rectangular sections with aspect ratios of 1.5 (strength gain up to 81%), and even 2 (up to 36%). The axial strength of the tests was compared with the design criteria of four international guidelines, resulting in predictions that did not properly fit for rectangular sections. A predictive equation is proposed to assess the axial compressive strength of the FRP-confined concrete, which includes a better adjustment for the strain efficiency factor and the shape factor for rectangular columns.

Efficacy of CFRP/BFRP laminates in flexurally strengthening of concrete beams with corroded reinforcement

This paper aimed at quantifying the effect of reinforcement corrosion level on the deformability and the flexural strengthening performance of Carbon and Basalt-Fibre-Reinforced Polymers (CFRP and BFRP) sheets on fifteen large-scale reinforced concrete (RC) beams. The main investigated parameters included reinforcement corrosion levels (0–30% by mass), FRP types and numbers of FRP layers (0–4 layers). The test results showed that the CFRP/BFRP laminates substantially reduced the crack width by up to 89%/85%. The flexural resistance of the corroded beams was, thus, improved by up to 103%/41%. By increasing the flexural resistance of corroded beams up to 41%, the BFRP laminates were a cost-effective strengthening option. Corrosion of the steel reinforcement resulted in the more effective mobilisation of the CFRP/BFRP laminates. This led to an increase in the strengthening effectiveness (improvement of beam flexural resistance) of the CFRP/BFRP laminates in the corroded beams by 14%/6% on average compared to the non-corroded beams. This increase tended to be more pronounced with a higher reinforcement corrosion level. In this paper, the authors propose an empirical formula to include the effect of reinforcement corrosion levels on FRP debonding strain. The proposed formula was verified showing an acceptable agreement with the experimental data from this study and other previous studies.

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.

Consideration of Critical Parameters for Improving the Efficiency of Concrete Structures Reinforced with FRP.

Fibre-reinforced polymer materials (FRP) are increasingly used to reinforce structural elements. Due to this, it is possible to increase the load-bearing capacity of polymer, wooden, concrete, and metal structures. In this article, the authors collected all the crucial aspects that influence the behaviour of concrete elements reinforced with FRP. The main types of FRP, their characterization, and their impact on the load-carrying capacity of a composite structure are discussed. The most significant aspects, such as type, number of FRP layers including fibre orientation, type of matrix, reinforcement of concrete columns, preparation of a concrete surface, fire-resistance aspects, recommended conditions for the lamination process, FRP laying methods, and design aspects were considered. Attention and special emphasis were focused on the description of the current research results related to various types of concrete reinforced with FRP composites. To understand which aspects should be taken into account when designing concrete reinforcement with composite materials, the main guidelines are presented in tabular form.

Structural response of high strength concrete beams using fiber reinforced polymers under reversed cyclic loading

This paper investigates the response of high strength concrete (HSC) beams subjected to reversed cyclic loading using carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymers (GFRP), and hybrid FRP/steel bars as bottom tensile reinforcement. Five HSC beams with a rectangular cross-section were prepared and poured using with a 28-day concrete compressive strength of 60 MPa (8.7 ksi). A displacement-controlled reversed cyclic loading has been applied to all the beams. The test setup has been designed to represent seismic effect on structures. Flexural capacity, concrete and reinforcement steel strains, cracking behavior, and ductility results were obtained. The hybrid steel/FRP has shown an improved performance in terms of flexural capacity, strains, and ductility. While the inclusion of FRP grids reduces the flexural capacity, this can be improved by adding more layers of FRP. Overall, the nominal moment of the hybrid sections were the highest between all beams. The ACI 318 code’s empirical equations showed close results in terms of the tensile strength of the FRP. The ACI 440R has shown overestimated nominal moment values compared to the experimental results.

Axial compressive behavior of CFRP confined rectangular CFT columns using high-strength materials: Numerical analysis and carrying capacity model

The concrete-filled steel tubular columns using high-strength steel and concrete have the advantages of high strength and small cross-section. However, the rectangular concrete-filled steel tubular (RCFT) columns using high-strength materials are susceptible to local buckling and lower ductility. The experimental study on the axial compression behavior of FRP confined concrete-filled steel tubular columns using high-strength materials show that FRP could restrain the deformation of steel tube and concrete and delay the local buckling of steel tube effectively. Based on the experimental study, the finite element model of FRP confined RCFT columns was established and verified by comparing the carrying capacity and load-displacement curves of test including ten specimens. Parametric analysis considering the corner radius, number of FRP layers, width-to-thickness ratio, concrete strength and aspect ratio is conducted to analyze the influence of different parameters on the axial compressive performance. Through the analysis of test and parametric data, theoretical model and method to design the axial capacity of the FRP confined RCFT columns are proposed. The theoretical models and methods could accurately predict ultimate carrying capacity of FRP-RCFT columns under axial compression and provided theoretical support for the application of FRP confined concrete-filled steel tubular columns using high-strength materials.

Experimental and analytical investigation of using externally bonded, hybrid, fiber-reinforced polymers to repair and strengthen heated, damaged RC beams in flexure

PurposeThis study aims to conduct an experimental study and finite element model (FEM) to investigate the flexural behavior of heat-damaged beams strengthened/repaired by hybrid fiber-reinforced polymers (HFRP).Design/methodology/approachTwo groups of beams of (150 × 250 × 1,200) mm were cast, strengthened and repaired using different configurations of HFRP and tested under four-point loadings. The first group was kept at room temperature, while the second group was exposed to a temperature of 400°C.FindingsIt was found that using multiple layers of carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) enhanced the strength more than a single layer. Also, the order of two layers of FRP showed no effect on flexural behavior of beams. Using a three-layer scheme (attaching the GFRP first and followed by two layers of CFRP) exhibited increase in ultimate load more than the scheme attached by CFRP first. Furthermore, the scheme HGC (heated beam repaired with glass and carbon, in sequence) allowed to achieve residual flexural capacity of specimen exposed to 400°C. Typical flexural failure was observed in control and heat-damaged beams, whereas the strengthened/repaired beams failed by cover separation and FRP debonding, however, specimen repaired with two layers of GFRP failed by FRP rupture. The FEM results showed good agreement with experimental results.Originality/valueFew researchers have studied the effects of HFRP on strengthening and repair of heated, damaged reinforced concrete (RC) beams. This paper investigates, both experimentally and analytically, the performance of externally strengthened and repaired RC beams, in flexure, with different FRP configurations of CFRP and GFRP.

Effect of Sulfate Attack on Reinforced Concrete Columns Confined with CFRP Sheets under Axial Compression

Sulfate ions in saltwater can considerably deteriorate the strength and durability of reinforced concrete (RC). To date, there has been no study that systematically investigates the effects of a sulfate attack on the capacity of mid-/large-scale RC columns confined with carbon fiber–reinforced polymer (CFRP). The capacity of CFRP-confined concrete columns subjected to sulfate attacks with various schemes and durations (up to 210 days) was examined in this study. The primary objectives of this study were to (1) examine the effect of a sulfate attack on the structural properties of midscale RC columns confined with CFRP; (2) quantify the contribution of the sulfate-damaged concrete core and CFRP confinement to the load-carrying capacity of the columns; and (3) propose a new formula to estimate the compressive strength of FRP-confined sulfate-damaged concrete considering the exposing time, number of FRP layers, and concrete strength. The experimental results showed that the sulfate attack significantly reduced the initial axial stiffness of the column up to 36% and increased its ultimate axial displacement up to about 40%. These influences in the CFRP-strengthened columns were slightly lower than those of unstrengthened ones. The sulfate attack considerably reduced the strength of the unstrengthened columns (up to 29.4%), but it only slightly affected the capacity of the strengthened columns with a 3.7% reduction. The strength reduction increased with the number of wet–dry cycles. CFRP confinement effectively mitigated the penetration of sulfate ions into the concrete core and, thus, slowed the degradation of the strength up to 90%. An empirical formula was proposed to estimate the strength of the CFRP-confined concrete subjected to a sulfate attack with close predictions regarding the experimental results.

Axial compressive behavior of seawater sea-sand coral aggregate concrete-filled circular FRP-steel composite tube columns

To better directly apply undisturbed seawater, sea sand and coral aggregates to ocean engineering, a new type of circular concrete-filled FRP-steel composite tube structure was designed. The core concrete is composed of sea sand as a fine aggregate, coral as a coarse aggregate and seawater as the mixing water. The FRP-steel composite tube is formed by wrapping FRP on the inner and outer walls of the steel tube. Thirty-six new circular seawater sea sand coral aggregate concrete (SSCC)-filled FRP-steel composite tube columns (SCCFCTs) were subjected to monotonic axial compression tests. The main test variables were the steel tube diameter-thickness ratio, FRP layers and FRP type. According to the different diameter-thickness ratios, the final failure mode of the specimen was divided into shear failure and extrusion expansion failure. The increase in the number of FRP layers and the decrease in the diameter-thickness ratio of the steel tube led to a significant improvement in the ultimate stress and strain of the specimens. When the other test parameters were kept the same, the CFRP-confined specimens had a higher ultimate strength and the BFRP-confined specimens had a slightly higher ultimate deformation capacity. Finally, the versatility of the existing model for the test data was evaluated and the complete stress–strain curve of the SCCFCTs under compression was simulated. The calculated results were satisfactory.