FRP Wrapping Research Articles

The Use of Externally Bonded Fibre Reinforced Polymer Composites to Enhance the Seismic Resilience of Single Shear Walls: A Nonlinear Time History Assessment

In medium- to high-rise buildings, single shear walls (SSWs) are often used to resist lateral force due to wind and earthquakes. They are designed to dissipate seismic energy mainly through plastic hinge zones at the base. However, they often display large post-earthquake deformations that can give rise to many economic and safety concerns within buildings. Hence, the primary objective of this research study is to minimize residual deformations in existing SSWs located in the Western and Eastern seismic zones of Canada, thereby enhancing their resilience and self-centering capacity. To that end, four SSWs of 20 and 15 stories, located in Vancouver and Montreal, were meticulously designed and detailed per the latest Canadian standards and codes. The study assessed the impact of three innovative strengthening schemes on the seismic response of these SSWs through 2D nonlinear time history (NLTH) analysis. All three strengthening schemes involved the application of Externally Bonded Fiber Reinforced Polymer (EB-FRP) to the shear walls. Accordingly, a total of 208 NLTH analyses were conducted to assess the effectiveness of all strengthening configurations. The findings unveiled that the most efficient technique for reducing residual drift in SSWs involved applying three layers of vertical FRP sheets to the extreme edges of the wall, full FRP wrapping the walls, and full FRP wrapping of the plastic hinge zone. Nevertheless, it is noteworthy that implementing these strengthening schemes may lead to an increase in bending moment and base shear force demands within the walls.

Performance evaluation and FRP strengthening of concrete-filled steel tubular columns subjected to vehicle impact

Concrete-filled steel tubular (CFST) columns have been widely used in multi-story and high-rise frame structures. During the service period, they may suffer vehicle impact due to traffic accidents or terrorist attacks. This paper numerically evaluates the performance of CFST columns under vehicle impact and investigates the effects of carbon FRP (CFRP) wrapping arrangements on performance improvement of the columns. Before that, a numerical model was developed to simulate the responses of CFST columns without and with FRP wrapping under vehicle impact and post-impact axial compression, and then calibrated by reported tests. Evaluation results show that the performance of CSFT columns under vehicle impact is divided into five levels, i.e., no repair required, rapid repair required, minor repair needed, major repair needed, and replacement needed. The performance level decreases with the increase in the vehicle weight or speed and increases with the increase in the column diameter or steel tube thickness. The column height has little effects on the performance level. A higher axial load ratio, e.g., 0.5, might reduce the performance level. Besides, a CFST column tends to fail in flexure mode when hit by F800 medium truck, while it may fail in flexure & shear mode when hit by C2500 pickup truck. Investigation results indicate that FRP wrapping with each layer orientation of 90° (i.e., in the longitudinal direction) and 0° (i.e., in the hoop direction) present the best performance improvement for a CFST column possibly undergoing flexure & shear and flexure failure, respectively. The increase of the number of FRP layers effectively improves the performance levels of CFST columns but the excessive demand may be not economical. It is not necessary to employ an FRP wrapping range of 100% for improving the vehicular impact performance level of a CFST column to the expected one.

Self-Centering Precast Unit as Energy Dissipation Members in Precast Segmental Bridge Columns

This research aims to present a new generation of seismic-resisting systems designed for precast reinforced concrete (RC) bridge piers in modern sustainable cities to withstand moderate to high seismic activity. The proposed system consists of two self-centering (SC) systems operating in parallel to bring together all features of the required resiliency during a seismic action. The first/main system is a hollow core precast segmental bridge column, and the second is composed of an SC precast unit and energy dissipation (ED) steel reinforcements positioned in the main pier segment’s hollow core. To study the performance of the proposed system, a finite element model was first developed to capture the behavior of experimentally tested precast bridge columns. After validation, the created model was systematically studied to investigate the performance of the entire proposed system under cyclic loading. The effects of three parameters related to the ED system were investigated, including the reinforcement ratio, the unbonded length of ED bars, and the SC post-tensioned force ratio. Furthermore, the impact of FRP wrapping on the lower part of the core column of the ED system was also investigated. An analytical model predicting the characteristic points of the lateral response of the proposed system based on the superposition concept is also proposed. The FE results showed that the entire proposed system is a new design-based resilient system with the ability to dissipate energy without compromising the SC capacity of the main resisting system. Compared to the typical precast hollow core segmental column, a 6% reinforcement ratio of the ED unit can cause a 60% increase in lateral resistance and a 220% increase in the ED capacity. The analytical model can successfully be applied in the design of the proposed system to provide customized ED capabilities and controlled lateral resistance.

Comparison and Enhancement of Design Procedures for Guideline Expressions to Predict the Compressive Capacity of FRP-Wrapped Concrete Members

The FRP wrapping of reinforced concrete columns is a simple way to increase the axial load capacity of such members with substandard concrete quality. A total of 2197 specimens were collected as a database to discuss the efficiency of predicting axial compressive strength of FRP-wrapped concrete columns according to several national and international guidelines. Various aspects of the database, including fiber type, unconfined strength and specimen geometry used to investigate the guidelines, and results are presented in terms of averages, standard deviations, and ratio of overestimated specimens. The performance of these expressions was compared with one another based on these statistical results and graphs, and those that captured the behavior best were identified for specific subsets. Recognizing the expressions’ inadequacy in capturing efficiency improvements related to radius to area and confinement ratios, some improvements in the form of coefficients for lateral confinement stress in the Turkish Building Earthquake Code were introduced, specifically for certain subsets.

Explainable Data-Driven Ensemble Learning Models for the Mechanical Properties Prediction of Concrete Confined by Aramid Fiber-Reinforced Polymer Wraps Using Generative Adversarial Networks

The current study offers a data-driven methodology to predict the ultimate strain and compressive strength of concrete reinforced by aramid FRP wraps. An experimental database was collected from the literature, on which seven different machine learning (ML) models were trained. The diameter and length of the cylindrical specimens, the compressive strength of unconfined concrete, the thickness, elasticity modulus and ultimate tensile strength of the FRP wrap were used as the input features of the machine learning models, to predict the ultimate strength and strain of the specimens. The experimental dataset was further enhanced with synthetic data using the tabular generative adversarial network (TGAN) approach. The machine learning models’ performances were compared to the predictions of the existing strain capacity and compressive strength prediction equations for aramid FRP-confined concrete. The accuracy of the predictive models was measured using state-of-the-art statistical metrics such as the coefficient of determination, mean absolute error and root mean squared error. On average, the machine learning models were found to perform better than the available equations in the literature. In particular, the extra trees regressor, XGBoost and K-nearest neighbors algorithms performed significantly better than the remaining algorithms, with R2 scores greater than 0.98. Furthermore, the SHapley Additive exPlanations (SHAP) method and individual conditional expectation (ICE) plots were used to visualize the effects of various input parameters on the predicted ultimate strain and strength values. The unconfined compressive strength of concrete and the ultimate tensile strength of the FRP wrap were found to have the greatest impact on the machine learning model outputs.

Simplified framework for economic convenience of base isolation as seismic retrofit solution for existing RC buildings

Modern seismic retrofit strategies aim at increasing the building safety under high intensity earthquakes and minimizing the possible damage and, in turn the expected economic losses (EAL) under frequent and low intensity earthquakes. Classic techniques based on tradition or innovative material such as steel jacketing or FRP wrapping aims at increasing the strength/ductility of reinforced concrete (RC) members, but they do not significantly act in reducing the engineering demand parameters EDPs such as acceleration and drift. On the other side innovative techniques such as base isolation are capable of combining the increase of seismic safety with the significant reduction of acceleration and drift demand on the superstructure, thus, resulting in a significant reduction of the EALs. Although the number of applications is significantly increasing in Italy, its wide use is discouraged by the high cost of installation. Considering the annual savings related to the reduction of the EALs, the payback time (PBT) of the economic investment in a retrofitting by using base isolation can be comparable to that of other techniques. However simple tools to easily assess the PBT knowing major building characteristics are currently not available.This paper proposes a novel framework to estimate the EALs and the PBT of RC buildings retrofitted by means of FRP or Base Isolation based on the main building characteristics (i.e. in-plane geometry, number of floors, seismic). It is implemented in a MATLAB code to perform NLTHs on simplified structural models and calculate the EALs by using the full PBEE framework and considering the uncertainties in the hazard, damage and loss analysis. The framework is validated against the results of a case study building analyzed by means of a refined 3D FEM model and calculating the EAL by means of the FEMA P-58 approach. A parametric study is carried out varying the concrete compressive strength and the reinforcement details to check the sensitivity of the framework to these variables. The preliminary results are presented and discussed.

Analysis of CFRP-confined CFST columns reinforced with steel angles under axial compression

To study the axial compression properties of specimens of concrete-filled steel tubes reinforced with steel angles, abbreviated as SRCFST, and of specimens of FRP-confined SRCFST, abbreviated as F-SRCFST, relevant finite element (FE) models were established using ABAQUS software. For verifying the accuracy of the proposed FE models, the axial load carried by each component of the specimen was first analysed and the distribution rules of the contact pressure between the steel tube and concrete as well as between the steel angles and concrete were analysed. In the second phase, the important parameters, such as the yield strength and wall thickness of the steel tube, the yield strength and cross-sectional area of the steel angles, the tensile strength and number of FRP wrapping layers were analysed. The third phase consisted of creating and proposing the design formulas for the SRCFST and F-SRCFST specimens on the basis of parametric analyses and numerical fitting method. The research results indicate that FRP has a minimal effect on the axial carrying capacity of the steel tube and the fundamental effect for the improved ultimate load is the indirect confinement effect by the FRP on the concrete. The proposed design formulas can accurately predict the ultimate load of SRCFST and F-SRCFST specimens, and the calculation error is generally within 10%.

Buckling behaviour of FRP strengthened cylindrical metallic shells with cut-outs

This paper presents a detailed buckling study on FRP strengthening of metallic cylindrical shells with different geometric imperfections and centrally located unstiffened and stiffened cut-outs. Initially, bare and FRP strengthened aluminium cylindrical shells have been manufactured. Geometric imperfections have been measured and implemented in the numerical model. Interfacial bond quality has been assessed by two different non-destructive techniques. The buckling response of bare and FRP strengthened shells have been numerically simulated and validated with respective experiments. Subsequently, the difference in buckling response between FRP strengthened and bare aluminium shells with variations in cut-out’s size, orientation, shape, and corner radius has been analysed for unstiffened cut-outs. The effect of increase in stiffener’s thickness and overlap width for photo-frame type stiffening of rectangular cut-outs with and without closure has been investigated. The study has revealed interesting observations. (1) Effect of cut-out size on buckling capacity of the shell is a function of its imperfection magnitude. For shells with large initial imperfections, introducing a cut-out as well as with increase in its size, relatively smaller drop in buckling capacity is found; while shells with small initial imperfections resulted in a steep and large drop in buckling load even with a small cut-out size. (2) FRP strengthening is more effective for shells with cut-outs compared to shells without cut-outs, as it increases the flexural stiffness of shell against asymmetric buckles’ initiation and resists outward lip opening along longitudinal edge of cut-out. (3) For shells with large initial imperfections, elliptical cut-outs offer higher buckling resistance than rectangular cut-outs with varying corner radius but with FRP wrapping, rectangular cut-outs with rounded edges exhibit the best buckling performance. (4) In the case of shells with stiffened cut-out, both with or without closure, FRP strengthening is effective only for shells with smaller initial imperfections. Further findings and observations are discussed and concluded.

RC beams retrofitted by FRP oriented in any direction: Influence of the effectiveness factors

Shear strength of FRP-retrofitted RC beams is usually influenced by different brittle failure modes characterizing the collapse of the FRP reinforcement. The most significant analytical models for assessing the shear strength of FRP-retrofitted RC beams reflect the effect of brittle failure through an effectiveness factor “R”, which reduces the ultimate tensile strength of FRP. The brittle collapse of FRP reinforcement often leads to a lower shear contribution by steel stirrups due to hindering of the yielding of all stirrups involved by critical cracking. Some analytical models consider this phenomenon introducing a further effectiveness factor “r”, which reduces the yielding strength of stirrups. The key differences characterizing many of the shear models are represented by the expressions used for assessment of the effectiveness factors. This paper focuses on the influence of effectiveness factor models in analytical predictions provided by different shear models. The reduction of the shear contribution of steel stirrups due to FRP brittle failure is modeled as dependent on the FRP wrapping scheme, through the ratio between FRP effective strain and steel yielding strain. To highlight the influence of the effectiveness factor for steel stirrups, two analyses are performed through different shear models, considering the effectiveness factor for FRP only, and considering the effectiveness factor for both FRP reinforcement and steel stirrups. The results are discussed considering two databases, one constituted by beams whose FRP reinforcement and steel stirrups are arranged at right angles to the beam axis, and one in which the FRP is arranged at angles different from 90°.

Influence of Cross-Section Shape and FRP Reinforcement Layout on Shear Capacity of Strengthened RC Beams.

The evaluation of the shear capacity of an FRP-strengthened reinforced-concrete beam is challenging due to the complex interaction between different contributions provided by the concrete, steel stirrup and FRP reinforcement. The shape of the beam and the FRP inclination can have paramount importance that is not often recognized by the models that are suggested by codes. The interaction among different resisting mechanisms has a significant effect on the shear capacity of beams, since it can cause a reduction in the efficiency of some resisting mechanisms. A comparative study of the performance in the shear resistance assessment provided by three models with six different effectiveness factors (R) is performed, considering different cross-section shapes, FRP wrapping schemes, inclination and anchorage systems. The results revealed that the cross-section shape, the FRP inclination and the efficiency of the FRP anchorages have a significant effect on the shear strength of beams. The analysis results show that the three models are able to provide an accurate average estimation of shear strength (but with a coefficient of variation up to 0.35) when FRP reinforcement orthogonal to the beam axis is considered, while a significant underestimation (up to 19%) affected the results for inclined FRP reinforcement. Moreover, all the models underestimated the resistance of beams with a T section.

Dolphin Mooring Structure Assessment PT. Smelting Gresik Due to Being Hit by a Mud Barge as a Basis for Repairing Structural Elements

A wharf or harbor is a complex of buildings connecting land and sea which functions as a place for mooring or docking of ships that will carry out the loading and unloading of goods or the boarding and falling of people (passengers) to and from the ship. Because the structure of the wharf is in the sea, incidents can occur either due to natural or human error. One of the incidents occurred at the mooring dolphin owned by PT. Smelting which was hit by a Mud Barge resulting in some damage to the structure. The case study taken is the Assessment activity on the Dolphin Mooring Structure owned by PT. Smelting. The assessment started by conducting a visual survey and the results showed that the damage occurred in the form of spalling and cracks in the concrete elements and also the peeling of the coating layer on the SPP. Furthermore, conducting tests in the field in the form of a UPV test and the results obtained that the density classification of the concrete is in a fairly good condition and the depth of the cracks that occur is still less than the minimum cover thickness. After that, under water testing was also carried out in the form of Thickness test and PIT, each of which resulted in the condition of the SPP pole still being in Fairly Good condition. And the last is destructive testing which is then used as a compressive test sample and the result is that the quality of the existing concrete still meets the quality limits for fc' 30 MPa according to SNI 6880-2016 code 1.5.6.2. Based on the tests that have been carried out, the Mooring structure is still able to function as it should, with some repairs to the damaged structures. For structures that are damaged by cracks, the suggestion for improvement that needs to be done is to inject using epoxy and for structures that are damaged by cracking & spalling, the suggestion for repairs that needs to be done is to do injection using grouting. Whereas in the SPP pole structure, the suggestion for improvement that needs to be done is to restore the initial layer consisting of HDPE and FRP Wrap. The Catwalk structure did not suffer any damage, it's just that the placement part failed due to corrosion and needed to be renewed. Based on several suggestions for improvements that need to be made, it can be estimated that the time for carrying out the work is 2 months or 60 calendar days.

Energy dissipation in reinforced concrete members before or after yielding

AbstractModels for the pre‐ and post‐yield energy dissipation in reinforced concrete (RC) members are developed using a database of about 1200 tests with over 18,000 load cycles. Before yielding, the equivalent viscous damping ratio exceeds 5%, especially if the member is initially uncracked. It can be considered by using either a dedicated pre‐yield hysteretic model with parameters established in the paper or global viscous damping and special provisions against double counting of energy dissipation. The post‐yield model can be combined with various post‐yield hysteretic laws. It accounts for the member's type, shear‐span‐to‐depth ratio and likely failure mode, the continuity, ratio, and surface characteristics of longitudinal bars, and for FRP wrapping, if any. Alternatively, it recognizes only four member types but accounts also for the transverse steel ratio and the normal stress due to the axial load.

Influence of FRP on the shear behaviour of RC rectangular beam elements

This article presents the outcomes of an experimental study on the shear behaviour of FRP strengthened RC beams. Shear deficient RC beams may exhibit brittle shear failure when the applied stress exceeds the designed level. Many strengthening measures, such as steel plate bonding, RC-jacketing etc., are efficient but laborious and not time effective solutions compared to the externally bonded FRP wrapping technique. External FRP wrapping is one of the efficient strengthening schemes in terms of its strength to weight ratio. This technique does not increase the structural member's cross-sectional size and dead load. The cost of FRP materials and mechanical properties also varies with respect to the type of fibre, thickness, and profile. In this study, RC beams of a/d ratio 1.25 have been used with CFRP and BFRP composites. The test results show a 17.98% increase in strength and improves ductility by 77%. The strengthening scheme increases the shear strength by controlling the early formation of diagonal cracks in the strengthened shear zone and exhibiting ductile failure. Triantafillou’s model has been validated with the test results of CFRP strengthened beams, and the proposed model has been verified using the experimental data and literature data collected. The proposed methodology works well in estimating the shear capacity of CFRP strengthened RC beams.

A framework for the lifecycle cost assessment of structures considering multiple mainshock-aftershock sequences

Structures in an earthquake-prone region have the potential to experience multiple mainshock-aftershock (MSAS) sequences during their lifetime. The multiple aftershocks of a given mainshock would further aggravate the damage extent of the mainshock-damaged structure, and meanwhile extend its recovery time. This manuscript proposes a probabilistic framework for lifecycle cost assessment of the structure under multiple MSAS sequences. This framework comprehensively considers the effects of repair status (i.e, finished repair or not) and uncertainties related to multiple MSAS sequences and damage state of the structure. Then this framework is applied to six 4-story reinforced concrete moment frames (i.e., one original structure and five retrofitted scenarios). The results indicate that ignoring repair status would underestimate the lifecycle cost by maximum level of 20%. Multiple aftershocks would increase the lifecycle cost of structures, and such an increment varies from 6% to 137% for different retrofitted scenarios. FRP wrapping is the best retrofit method while Shear wall is the worst one from the perspective of lifecycle cost.

Effect of steel–FRP ratio and FRP wrapping layers on tensile properties of glass FRP-wrapped ribbed steel reinforcing bars

Effect of steel–FRP ratio and FRP wrapping layers on tensile properties of glass FRP-wrapped ribbed steel reinforcing bars

A passive stress-strain model for concrete prisms reinforced by a combination of confinement reinforcement

The strength and ductility of concrete prisms can be significantly enhanced by confinement reinforcement, such as stirrups, wraps, and tubes. Recently, a combination of confinement reinforcement is applied to concrete prisms for their better ductility or a specific use. However, most existing approaches only give the ultimate strength of confined concrete prisms and do not consider the size effect. As a result, these approaches cannot provide structural engineers with a simple tool for the ductility design of concrete prisms with size effect. In this paper, based on the fundamental partial interaction bond-slip and shear-friction mechanisms, a passive stress–strain model of concrete confined by a combination of confinement reinforcement is proposed. The main advantages of the proposed model are that the size effect is considered and it can be applied to concrete members of rectangular or circular cross-section reinforced by novel combinations of confinement reinforcement. After the proposed model is verified with test results of concrete prisms reinforced by FRP wrapping and stirrups/steel tube, it is concluded that this model can be applied in the ductility design of FRP wrapped concrete prisms.

Experimental Comparison of Different Types of FRP Wrapping in Repairing of RC Deep Beams with Circular Openings

Openings of RC deep beams can be used to pass electrical, mechanical, and architectural equipment. These openings can reduce the bearing capacity. Previous studies showed that carbon fiber reinforced polymer (CFRP) sheets could influence RC deep beams' ductility and bearing capacity. In this laboratory reearch, the the impact of aramid and glass fiber reinforced polymer (AFRP and GFRP) sheets on the retrofitting of RC deep beams with the circular opening was investigated. Their response was compared with the performance of CFRP sheets. Depending on the layers (1, 2 and, 3), AFRP, GFRP, and GFRP sheets increased the maximum load of the beams by about 65 to 94%, 87 to 130%, and 133 to 196%, respectively. In RC deep beams retrofitted with GFRP sheets, the sheet separation from the beam surface decreased with expanding the number of layers. The CFRP sheets debonded from the beam surface at the supports along the center of the circular opening. CFRP showed much better performance in energy absorption capacity and load capacity than AFRP and GFRP. The CFRP were debonded from the beam surface at the moment of rupture. However, no significant separation was observed in RC deep beams retrofitted with AFRP and GFRP sheets. SEM images of the cores specimens showed that the fracture surface of the specimens extracted from the beam retrofitted with GFRP and CFRP sheets was much rougher than the control specimen, which indicates a stronger bond between the concrete components.

Effectiveness of FRP strengthening on buckling characteristics of metallic cylindrical shells

Buckling performance of thin metallic shells can be enhanced by external wrapping of FRP composite layers. But the effectiveness and the extent of such FRP strengthening is influenced by the buckling characteristics of the metallic shell. This paper presents a detailed numerical study to bring out the changes in buckling behaviour and buckling modes of metallic cylindrical shells of different r/t ratios, exhibiting all varieties of buckling viz. elastic, axisymmetric plastic, and asymmetric plastic, due to changes in the hoop and longitudinal stiffness of the FRP wrap. The most general buckling behaviour of the FRP strengthened shells exhibiting elastic, pre-strain localization, post strain localization, axisymmetric buckle growth, and the asymmetric buckle growth stages are being brought out. Subsequently, the influence of parameters viz. r/t ratio, modulus and yield strength of the metallic shell, and the type and magnitude of the FRP strengthening on this general buckling behaviour are analysed. The results demonstrate that 1) the elastic buckling shells display a stepwise increase in load capacity with an increase in hoop modulus of the FRP wrap; 2) for the plastic buckling shells undergoing asymmetric buckling modes, a minimal increase in longitudinal stiffness of FRP wrap, just sufficient to reach the shells’ yield capacity, would lead to an optimal design; and 3) for the plastic buckling shells failing due to axi-symmetric bulging at their ends, the increase in longitudinal stiffness of FRP, increases both the yield capacity and the pre-strain localization stiffness, leading to a large increase in buckling capacity.

Cost and EAL based optimization for seismic reinforcement of RC structures

In this paper, a new genetic algorithm-based framework aimed at efficiently design multiple seismic retrofitting interventions is proposed. The algorithm focuses on the minimization of retrofitting intervention costs of reinforced concrete (RC) frame structures. The feasibility of each tentative solution is assessed by considering in an indirect way the expected annual loss (EAL), this evaluation is performed by referring to different limit states whose repairing costs are expressed as a percentage of reconstruction costs and evaluating the respective mean annual frequency of exceedance. As the EAL takes into account the overall structural performances, to involves both serviceability and ultimate limit states, two different seismic retrofitting techniques are considered. In particular, FRP wrapping of columns is employed to increase the ductility of RC elements managing life safety and collapse limit state demands. On the other hand, steel bracings are used to increase the global stiffness of the structure and mainly increase operational and damage limit states performances. The optimization procedure is carried out by the novel genetic algorithm-based framework developed in Matlab® that is connected to a 3D RC frame fiber-section model implemented in OpenSees. For both the retrofitting systems, the algorithm provides their position within the structure (topological optimization) and their sizing. Results will show that seismic retrofitting can be effectively designed to increase the overall structural safety by efficaciously optimizing the intervention costs.

Ductility Behaviour of Rectangular Compression Members Retrofitted by Modified Technique of FRP Wrapping

This paper presents an experimental investigation on ductility behaviour of reinforced concrete compression members, rectangular in cross section, modified to elliptical shape in cross section by bonding precast segment covers followed by Carbon Fiber Reinforced Polymer wrapping (CFRP) under concentric and eccentric loading conditions. Eighteen reinforced concrete rectangular compression members of size 100mm×150mm in cross section and 300mm in height were prepared using normal-strength concrete. Reinforcement ratio was kept at minimum, to simulate compression members that need retrofitting. Out of eighteen specimens, nine specimens were converted to elliptical shape in cross section. From nine remaining rectangular specimens, three specimens retained as it is without wrapping FRP and designated as Group1, remaining six specimens were wrapped with one and two layers of CFRP and designated as Group2. Out of nine elliptical specimens, three specimens were retained as it is without wrapping FRP and designated as Group3, remaining six elliptical specimens were wrapped with one and two layers of CFRP and designated as Group4. Specimens were tested upto failure under monotonic axial compression with concentric and eccentric load conditions. From the experimental results, it is observed that rectangular compression members shape modified to ellipse in cross section and then wrapped with CFRP show outstanding increase in the ultimate load carrying capacity which may be due to increased cross sectional area and effective confinement of FRP wrapping. As the number of layers of CFRP increases the ultimate load carrying capacity increases. With increase in eccentricity, the ultimate loads of the compression members were found to be decreased. Elliptical specimens wrapped with one and two layers of CFRP reported exponential increase in deformation ductility under concentric load condition and considerable increase under eccentric load condition compared to rectangular specimens wrapped with CFRP.