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Retrofitting RC beam-column joint subassemblies using UHPC jackets reinforced with high-strength steel mesh
Abstract Outdated building codes in seismic zones often did not require seismic detailing on beam-column joints, leaving many existing structures vulnerable to earthquakes. To address this issue, three different ultra-high-performance concrete (UHPC) jackets were proposed for retrofitting seismically-deficient exterior beam-column joints, with variables including construction method (cast-in-place or precast) and inclusion of high-strength steel bar meshes. The effectiveness of these jackets was investigated using cyclic loading tests on beam-column joint subassemblages. The results demonstrated that all three UHPC jackets considerably improved the strength, stiffness, and energy dissipation of the beam-column joint subassemblage, as well as both repairable and collapse drifts. However, the cast-in-place UHPC jacket, when not reinforced with steel meshes, failed to effectively improve the ultimate drift capacity of the original beam-column joint subassemblage. Moreover, retrofitting with precast UHPC jackets using chemical anchors failed to generate sufficient composite action. Only the cast-in-place UHPC jacket, when reinforced with high-strength steel meshes, successfully delayed localized joint shear damage and allowed for effective utilization of beam flexural capacity. It improved the joint shear strength by 66%, initial stiffness by approximately 35%, and total energy dissipation by 140%. Finally, strength models were suggested for evaluating the joint shear strength and beam flexural capacity of UHPC-retrofitted beam-column joints.
Highlights UHPC jackets were reinforced with high-strength steel bar meshes. Cast-in-situ UHPC jacketing outperformed precast UHPC jacketing. Cast-in-situ UHPC jacketing with steel mesh improved joint shear failure. Tension stiffening of UHPC was beneficial in stress redistribution. Models reasonably predicted the specimen strength and failure pattern.
Retrofitting RC beam-column joint subassemblies using UHPC jackets reinforced with high-strength steel mesh
Abstract Outdated building codes in seismic zones often did not require seismic detailing on beam-column joints, leaving many existing structures vulnerable to earthquakes. To address this issue, three different ultra-high-performance concrete (UHPC) jackets were proposed for retrofitting seismically-deficient exterior beam-column joints, with variables including construction method (cast-in-place or precast) and inclusion of high-strength steel bar meshes. The effectiveness of these jackets was investigated using cyclic loading tests on beam-column joint subassemblages. The results demonstrated that all three UHPC jackets considerably improved the strength, stiffness, and energy dissipation of the beam-column joint subassemblage, as well as both repairable and collapse drifts. However, the cast-in-place UHPC jacket, when not reinforced with steel meshes, failed to effectively improve the ultimate drift capacity of the original beam-column joint subassemblage. Moreover, retrofitting with precast UHPC jackets using chemical anchors failed to generate sufficient composite action. Only the cast-in-place UHPC jacket, when reinforced with high-strength steel meshes, successfully delayed localized joint shear damage and allowed for effective utilization of beam flexural capacity. It improved the joint shear strength by 66%, initial stiffness by approximately 35%, and total energy dissipation by 140%. Finally, strength models were suggested for evaluating the joint shear strength and beam flexural capacity of UHPC-retrofitted beam-column joints.
Highlights UHPC jackets were reinforced with high-strength steel bar meshes. Cast-in-situ UHPC jacketing outperformed precast UHPC jacketing. Cast-in-situ UHPC jacketing with steel mesh improved joint shear failure. Tension stiffening of UHPC was beneficial in stress redistribution. Models reasonably predicted the specimen strength and failure pattern.
Retrofitting RC beam-column joint subassemblies using UHPC jackets reinforced with high-strength steel mesh
Hung, Chung-Chan (author) / Hsiao, Hsin-Jui (author)
Engineering Structures ; 305
2024-02-26
Article (Journal)
Electronic Resource
English
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