Shear behaviour of beams strengthened using different Ni-Ti-Nb shape memory alloy wire configurations and design proposal based on the compression chord Capacity model (CCCM). (1st October 2022)

• Record Type: Journal Article
• Authors: Rius, Joan M.; Cladera, Antoni; Mas, Benito; Ribas, Carlos
• Is Part Of: Engineering structures. Volume 268(2022)
• Publication Date: 2022-10-01
• Subjects: Ni-Ti-Nb -- Shape memory effect -- Shear strength -- Reinforced concrete -- Strengthening; Structural engineering -- Periodicals; Structural analysis (Engineering) -- Periodicals; Construction, Technique de la -- Périodiques; Génie parasismique -- Périodiques; Pression du vent -- Périodiques; Earthquake engineering; Structural engineering; Wind-pressure; Periodicals; 624.105
• DOI: 10.1016/j.engstruct.2022.114724
• Languages: English
• ISSNs: 0141-0296

Abstract

Highlights: U-shaped SMA wires as active shear strengthening (SS) for RC beams. Spiral wire implanted in a groove at lower part of the RC beam as active SS. Spiral wire confining the compressed chord as active SS for RC beams. U-stirrups have lower initial imperfection and higher initial stress to confine. Compression Chord Capacity Model (CCCM) CCCM able to predict shear strength of RC beams with active SS. Abstract: Shear strengthening of existing structures is often required in cases where shear strength is deficient because shear failures in RC members are associated with brittle collapse. In previous papers, the authors presented an innovative system for active strengthening shear critical-reinforced concrete (RC) beams using shape memory alloys (SMA) to take advantage of the shape memory effect. The authors also presented an approach to design this type of reinforcement based on the Compression Chord Capacity Model (CCCM). This model considers several shear transfer actions, including increased shear strength of the concrete compressed chord due to its confinement. This article presents an experimental study of RC beams with new types of SMA strengthening systems that also improve the shear behaviour of beams. The new types of tested shear strengthening systems are U-shaped external wires to facilitate the construction process by reducing initial imperfections; spiral active SMA wire implanted into a groove in the lower RC specimen part to see if it improves the dowel action effect; spiral active SMA wire only confining the compressed chord to check whether the CCCM predictions in this regard are adequate.