Confinement effects of unidirectional CFRP sheets on axial and bending capacities of square RC columns

Strengthening of reinforced concrete (RC) columns is needed when the actual load-carrying capacity of the columns does not reach the required level due to either structural deterioration or increasing acting loads. This experimental study aims to evaluate the strengthening effect on the eccentrically-compressed RC columns using Carbon fiber reinforced polymer (CFRP) sheets, that confine around the column cross-section. Three RC column specimens with the same geometrical dimensions, reinforcement detailing, and concrete compressive strength were cast and tested in the current experimental investigation. One RC column without being strengthened is referred as the control specimen whereas two other RC columns were partially strengthened by CFRP sheets. All three RC columns were axially loaded with the same initial eccentricity e0 of 80 mm. Based on the test results such as the ultimate load-carrying capacity, the load-rotation relationship, and load-curvature at the middle of column height, the effectiveness of the strengthening technique is discussed.

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Experimental study on seismic strengthening of RC columns with wrapped CFRP sheets

Construction and Building Materials ◽

10.1016/s0950-0618(03)00047-3 ◽

2003 ◽

Vol 17 (6-7) ◽

pp. 499-506 ◽

Cited By ~ 49

Author(s):

L.P. Ye ◽

K. Zhang ◽

S.H. Zhao ◽

P. Feng

Keyword(s):

Experimental Study ◽

Seismic Strengthening ◽

Rc Columns ◽

Cfrp Sheets

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Experimental Investigation of RC Columns Confined with Ni-Ti Shape Memory Alloys Wires versus CFRP Sheets

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2019-0511 ◽

2020 ◽

Author(s):

Khaled Abdelrahman ◽

Raafat El-Hacha

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Nickel Titanium ◽

Superior Performance ◽

Heating Process ◽

Compression Tests ◽

Rc Columns ◽

Cfrp Sheets ◽

Confinement System ◽

Cfrp Confinement

The critical need to enhance existing strengthening methods with more efficient and effective ones has led to the evolvement of smarter and innovative class of materials termed Shape Memory Alloys (SMA). The SMA’s possess unique characteristic properties that lie in their ability to undergo large deformations and return to their undeformed shape through stress removal or heating process. Limited research studies conducted using SMA’s have shown high potential for their use in building industry. Results presented in this research study are from an experimental study that investigated the compressive behaviour of uniaxial concentrically loaded Nickel – Titanium (Ni-Ti) SMA-spirally confined RC columns and compared with RC columns confined with conventional CFRP sheets. The compression tests revealed that actively confining the concrete column with Ni-Ti SMA spiral wires increased the performance of the concrete dramatically. Additionally, the active Ni-Ti SMA-confinement system exhibited superior performance compared to the conventional passive CFRP-confinement system.

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