Seismic Retrofit of Substandard RC Columns Using Sprayed Glass Fiber-Reinforced Mortar and Basalt Textile Reinforcement

ABSTRACT

This study investigates the seismic retrofit of substandard reinforced concrete (RC) columns through external jacketing of potential plastic hinge zones using sprayed glass fiber-reinforced mortar and basalt textile reinforcement. An innovative spraying method was used to apply the matrix material to the concrete surface. A total number of eight full-scale columns (four reference, four retrofitted) were tested under constant high axial load to capacity ratio and reversed cyclic lateral loading. Columns were constructed using low-strength concrete and transverse reinforcement with various spacing and inadequate hook detailing to mimic the columns in substandard structures. Test results are evaluated in terms of lateral load-drift ratio relationships, displacement ductility, stiffness degradation, energy dissipation, and residual displacements. Evaluation of the test results showed that the proposed technique is effective for seismic retrofit of substandard RC columns, particularly in terms of enhancement of displacement ductility, energy dissipation capacities, and reduction of residual displacements.

KEYWORDS:

• Seismic retrofit
• substandard columns
• cement-based composites
• external jacketing
• TRM

Acknowledgments

The authors acknowledge Dr. Medine Ispir, and the company Fibrobeton for their great support during the planning, construction, and retrofitting processes of the test specimens. The administration and staff members of the Structural and Earthquake Engineering Laboratory of Istanbul Technical University are also acknowledged.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Data Availability Statement

Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.