Experimental research on eccentric compression of reinforced concrete columns strengthened by prestressed PET straps and angle steel

The mechanical behaviors of 12 high predamaged reinforced concrete (RC) rectangular columns strengthened with carbon fiber reinforced polymer (CFRP) under eccentric compression were experimentally investigated. The effects of the predamaged degree (δ), CFRP strips spacing (s f ) and eccentricity (e) on failure mode, bearing capacity, strain behaviors of CFRP strengthened predamaged columns were examined systematically. Test results demonstrated that the strengthened RC columns with small-eccentricity were destroyed by the yielding of compressive longitudinal steel bars and the crushing of compression concrete while the transverse CFRP strips were not ruptured. The failure mode of the strengthened RC columns with large-eccentricity was distinguished by the yielding of tensile and compressive longitudinal steel bars, the rupturing of longitudinal CFRP sheet, and the crushing of compressive concrete. With the increase of predamaged degree or eccentricity, the maximum bearing capacity of specimens decreased. In contrast, CFRP strips spacing had little effect on bearing capacity. Considering the effect of predamaged degree and eccentricity, a modified model for conveniently predicting the stress-strain relationship of CFRP strengthened predamaged RC columns under eccentric compression was proposed. On the basis of experimental study, the influence coefficients of predamaged degree and eccentricity and a strain distribution coefficient of CFRP strips were introduced, a calculation formula for predicting bearing capacity of high predamaged rectangular RC columns strengthened with CFRP under eccentric compression was proposed and validated test data with good agreement.bearing capacity, concrete column, damaged degree, eccentric loading, failure mode, fiberreinforced polymer, reinforcement, stress-strain relationship Discussion on this paper must be submitted within two months of the print publication. The discussion will then be published in print, along with the authors' closure, if any, approximately nine months after the print publication.

Section: Test Results and Analysismentioning

confidence: 84%

Experimental study on the eccentric performances of high predamaged rectangular reinforced concrete columns strengthened with carbon fiber reinforced polymer

Zou

Fang

et al. 2022

“…Anggawidjaja et al 46 wrapped piers with PET to improve their shear deformation capacity. Subsequently, Si et al 47 used composite reinforcement and utility model packaging materials to strengthen reinforced concrete columns, showing that prestressed PET‐cladding steel composite reinforcement can effectively inhibit the generation and development of cracks, thereby improving the ultimate bearing capacity of the strength and ductility of components. Based on the test, Si et al 48 established a finite element simulation model of prestressed PET strips and angle steel reinforced columns, carried out the multiparameter analysis of the eccentricity distance, PET spacing, and reinforcement methods, and established a small eccentricity of composite reinforced columns.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on flexural performance of reinforced concrete beams strengthened by PET

Liu

et al. 2023

Polyethylene terephthalate (PET) is a new type of fiber‐reinforced polymer (FRP) composite material, which has the characteristics of high performance, high toughness, high tensile fracture load, low elongation, low creep, no rust, and safety in use. The good performance of PET can significantly improve the mechanical properties of its components. A total of six reinforced concrete (RC) beams were produced in the test, one of which was a comparison beam, and the other five were reinforced with PET. In the test, the PET reinforcement spacing, number of reinforcement layers, and laying method were used as control variables, and an experimental study on the normal section bending performance of the specimen was performed. The test analyses the failure characteristics, crack width, bearing capacity, and deflection of the specimens under different reinforcement conditions. The test results showed that PET reinforcement can effectively inhibit the occurrence and development of cracks in RC beams and improve the ultimate bearing capacity and ductility of the components. The smaller the PET reinforcement spacing, the higher the ultimate bearing capacity; the greater the number of PET layers, the better the ductility of the specimen. Additionally, the economy, environmental protection, and portability of PET are of great significance for its application in practical engineering reinforcement.

“…There were many common strengthening methods, including increasing section, replacing concrete, outsourcing section steel, sticking FRP, adding support, and adding shear wall. [3][4][5][6][7][8] Isaac et al 9,10 verified that the structural properties of steel section concrete were superior to those of traditional RC structures. Adam et al 11 strengthened RC columns with external section steel and verified the feasibility of strengthening through axial compression test study and finite element software modeling analysis of specimens.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the seismic performance of strengthening RC frame structures had been extensively studied. There were many common strengthening methods, including increasing section, replacing concrete, outsourcing section steel, sticking FRP, adding support, and adding shear wall 3–8 . Isaac et al 9,10 verified that the structural properties of steel section concrete were superior to those of traditional RC structures.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the influence on structural seismic performance by the composite reinforcement method

Chu

et al. 2023

This paper proposed three composite strengthening methods for repairing seismic‐damaged RC frames to restore their seismic capacity. Combined with the damage characteristics and failure mode of the frame under the earthquake action, the local strengthening of the column adopts the angle steel and gusset plate, and then the whole frame is strengthened by the inclined brace, the thin‐walled steel plate and the V‐shaped buckling restrained brace (BRB), respectively. Through the cyclic loading test, the main seismic indexes of the strengthened specimen, including hysteresis curve, skeleton curve, ductility, energy dissipation capacity, and stiffness degradation, are studied. The influence of different strengthening methods on the seismic performance of the seismic‐damaged specimens is analyzed. The results show that the seismic performance of strengthened specimens is significantly improved, and the bearing capacity, ductility, and energy dissipation capacity are increased by 2.58–5.57, 1.05–1.24, and 7.67–15.87 times, respectively. The thin‐walled steel plate shear wall and the inclined brace are destroyed at first during loading to effectively delay the premature destruction of the main frame. The composite strengthening method makes the original frame realize the failure mechanism of “strong joint weak member, strong column weak beam” under strong earthquake action. The strengthened specimen satisfies the seismic requirement and has good seismic performance. The seismic performance of the frame strengthened with the V‐shaped BRB is better than that of the other two strengthening methods. Based on the test date, the formula for calculating the shear‐bearing capacity of the beam end is presented.