Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints

The effectiveness of an innovative retrofit scheme using near-surface-mounted (NSM) X-shaped CFRP ropes for the strengthening of substandard RC beam–column joints was investigated experimentally. Three large-scale beam–column joint subassemblages were constructed with poor reinforcement details. One...

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Main Authors: George Kalogeropoulos, Georgia Nikolopoulou, Evangelia-Tsampika Gianniki, Avraam Konstantinidis, Chris Karayannis
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/15/14/2409
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author George Kalogeropoulos
Georgia Nikolopoulou
Evangelia-Tsampika Gianniki
Avraam Konstantinidis
Chris Karayannis
author_facet George Kalogeropoulos
Georgia Nikolopoulou
Evangelia-Tsampika Gianniki
Avraam Konstantinidis
Chris Karayannis
author_sort George Kalogeropoulos
collection DOAJ
description The effectiveness of an innovative retrofit scheme using near-surface-mounted (NSM) X-shaped CFRP ropes for the strengthening of substandard RC beam–column joints was investigated experimentally. Three large-scale beam–column joint subassemblages were constructed with poor reinforcement details. One specimen was subjected to cyclic lateral loading, exhibited shear failure of the joint region and was used as the control specimen. The other specimens were retrofitted and subsequently subjected to the same history of incremental lateral displacement amplitudes with the control subassemblage. The retrofitting was characterized by low labor demands and included wrapping of NSM CFPR-ropes in the two diagonal directions on both lateral sides of the joint as shear reinforcement. Single or double wrapping of the joint was performed, while weights were suspended to prevent the loose placement of the ropes in the grooves. A significant improvement in the seismic performance of the retrofitted specimens was observed with respect to the control specimen, regarding strength and ductility. The proposed innovative scheme effectively prevented shear failure of the joint by shifting the damage in the beam, and the retrofitted specimens showed a more dissipating hysteresis behavior without significant loss of lateral strength and axial load-bearing capacity. The cumulative energy dissipation capacity of the strengthened specimens increased by 105.38% and 122.23% with respect to the control specimen.
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spelling doaj-art-d1d5784ade2d4607920c9e28d442c8e72025-08-20T03:07:54ZengMDPI AGBuildings2075-53092025-07-011514240910.3390/buildings15142409Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC JointsGeorge Kalogeropoulos0Georgia Nikolopoulou1Evangelia-Tsampika Gianniki2Avraam Konstantinidis3Chris Karayannis4Laboratory of Reinforced Concrete and Masonry Structures, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceLaboratory of Reinforced Concrete and Masonry Structures, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceLaboratory of Reinforced Concrete and Masonry Structures, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceLaboratory of Engineering Mechanics, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceLaboratory of Reinforced Concrete and Masonry Structures, Department of Civil Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceThe effectiveness of an innovative retrofit scheme using near-surface-mounted (NSM) X-shaped CFRP ropes for the strengthening of substandard RC beam–column joints was investigated experimentally. Three large-scale beam–column joint subassemblages were constructed with poor reinforcement details. One specimen was subjected to cyclic lateral loading, exhibited shear failure of the joint region and was used as the control specimen. The other specimens were retrofitted and subsequently subjected to the same history of incremental lateral displacement amplitudes with the control subassemblage. The retrofitting was characterized by low labor demands and included wrapping of NSM CFPR-ropes in the two diagonal directions on both lateral sides of the joint as shear reinforcement. Single or double wrapping of the joint was performed, while weights were suspended to prevent the loose placement of the ropes in the grooves. A significant improvement in the seismic performance of the retrofitted specimens was observed with respect to the control specimen, regarding strength and ductility. The proposed innovative scheme effectively prevented shear failure of the joint by shifting the damage in the beam, and the retrofitted specimens showed a more dissipating hysteresis behavior without significant loss of lateral strength and axial load-bearing capacity. The cumulative energy dissipation capacity of the strengthened specimens increased by 105.38% and 122.23% with respect to the control specimen.https://www.mdpi.com/2075-5309/15/14/2409beam–column jointsCFRP ropesseismic retrofitjoint shear failureanchorages
spellingShingle George Kalogeropoulos
Georgia Nikolopoulou
Evangelia-Tsampika Gianniki
Avraam Konstantinidis
Chris Karayannis
Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
Buildings
beam–column joints
CFRP ropes
seismic retrofit
joint shear failure
anchorages
title Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
title_full Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
title_fullStr Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
title_full_unstemmed Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
title_short Near-Surface-Mounted CFRP Ropes as External Shear Reinforcement for the Rehabilitation of Substandard RC Joints
title_sort near surface mounted cfrp ropes as external shear reinforcement for the rehabilitation of substandard rc joints
topic beam–column joints
CFRP ropes
seismic retrofit
joint shear failure
anchorages
url https://www.mdpi.com/2075-5309/15/14/2409
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