Numerical modeling of thermo-mechanical performance of small-scale CFRP reinforced concrete specimen using near surface mounted reinforcement method

This experimental study focuses on the retrofitting of reinforced concrete columns subjected to axial compression loading with different eccentricities. The proposed hybrid retrofitting technique incorporates two components: near-surface-mounted longitudinal steel rebars and transverse carbon-fiber-reinforced polymer straps. The latter was implemented to preclude buckling of the near-surface-mounted steel rebars under compression, to postpone debonding of near-surface-mounted steel rebars, to increase shear capacity of columns, and to improve the confinement level of concrete. The efficiency of the adopted retrofitting technique was evaluated through experimental testing of undamaged and damaged columns. Toward this, a total of 20 small-scale reinforced concrete circular columns including 5 control, 5 repaired, and 10 strengthened specimens were tested. All specimens were built to be identical with a diameter of 150 mm and a height of 500 mm. The specimens were tested under pure compression, combined axial–flexural (with eccentricities of 30, 60, and 90 mm), and four-point flexural loadings. Comparison of the results showed the efficacy of the proposed retrofitting strategy in enhancing the structural performance of both the undamaged and damaged columns in terms of loading capacity, ultimate displacement, and ductility factor. Finally, the axial load–bending moment interaction curves were discussed for all the tested columns.

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Inclusion of CFRP-Epoxy Composite for End Anchorage in NSM-Epoxy Strengthened Beams

Advances in Materials Science and Engineering ◽

10.1155/2015/812797 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Md. Akter Hosen ◽

Mohd Zamin Jumaat ◽

A. B. M. Saiful Islam

Keyword(s):

Reinforced Concrete ◽

Failure Modes ◽

Concrete Cover ◽

Structural Members ◽

Premature Failure ◽

Near Surface ◽

Steel Bars ◽

Near Surface Mounted ◽

Separation Failure ◽

Concrete Cover Separation

Nowadays, the use of near surface mounted (NSM) technique strengthening reinforced concrete (RC) structural members is going very popular. The failure modes of NSM strengthened reinforced concrete (RC) beams have been shown to be largely due to premature failure such as concrete cover separation. In this study, CFRP U-wrap end anchorage with CFRP fabrics was used to eliminate the concrete cover separation failure. A total of eight RC rectangular beam specimens of 125 mm width, 250 mm depth, and 2300 mm length were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM steel bars and the remaining four specimens were strengthened with NSM steel bars together with the U-wrap end anchorage. The experimental results showed that wrapped strengthened beams had higher flexural strength and superior ductility performance. The results also show that these beams had less deflection, strain, crack width, and spacing.

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