## 7 Conclusions  
This research emphasizes the substantial efficacy of the innovative TnT BRB system as a seismic retrofitting method specifically designed to enhance the resilience of RC beam-column joints. Comprehensive experimental investigations conducted via shake table testing clearly highlighted critical shortcomings inherent in conventionally designed non-ductile RC structures. Such structural systems exhibited pronounced brittle shear failures, substantial lateral displacements, and significant joint degradation under cyclic seismic excitations. These observed vulnerabilities underscore the pressing need for robust and effective seismic retrofitting strategies for existing infrastructure.  
Conversely, the integration of TnT BRBs resulted in considerable enhancements in seismic performance. The retrofitted RC frames demonstrated notable reductions in lateral drift, improved capacity for energy dissipation, and sustained integrity of key structural joints. The substantial mitigation of structural damage progression and enhanced global stability under seismic loading clearly illustrates the transformative potential of the proposed retrofitting solution.  
The value of this investigation is amplified through the integration of advanced analytical techniques, particularly sophisticated fiber-based FE modeling. This analytical approach effectively captured complex structural responses, such as hysteretic behaviors, localized damage phenomena, stiffness deterioration, and energy dissipation. Although the fiber-based FE element model provides key insights into the seismic performance of RC structures, its limitations in capturing complex localized behaviors must be acknowledged. Future research should prioritize hybrid modeling techniques that combine the strengths of fiber-based frameworks with detailed models of localized damage.  
As a conclusion, this study effectively bridges empirical and analytical methodologies, providing critical insights and validated tools for seismic rehabilitation of vulnerable RC structures. This integrated framework represents a significant contribution to both theoretical knowledge and practical application, offering valuable guidance for ongoing and future research efforts, as well as enhancing seismic design standards and resilience strategies within earthquake engineering. Future research should focus on optimizing the design parameters of TnT BRBs, exploring their long-term durability, and assessing their applicability across a broader range of structural configurations.  
Conceptualization, E.O. and R.O.; methodology, E.O., R.O., O.S. and A.H.; software, R.O.; validation, E.O. and R.O.; formal analysis, E.O.; investigation, E.O.; resources, E.O. and R.O.; data curation, E.O. and R.O.; writing--original draft preparation, E.O.; writing--review and editing, E.O., O.S. and R.O.; visualization, E.O.; supervision, A.H., B.A. and J.S. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
This empirical research was carried out utilizing a shake table situated at the Allianz Teknik Earthquake and Fire Test and Training Center in Istanbul, Turkiye. The authors express their genuine gratitude to all personnel involved for their significant input. Furthermore, appreciation is conveyed to ORTAS Celik for their assistance. It is important to note that the perspectives articulated in this paper are solely those of the authors and do not inherently represent the opinions of those acknowledged.  
The authors declare no conflicts of interest.