RUJOI

RUJOI introduces a new paradigm for the seismic design and retrofitting of reinforced concrete (RC) buildings by developing low‑cost, flexible, and highly dissipative deformable joints. These innovative rubber‑ and polyurethane‑based elements are strategically placed between the masonry infill and the RC frame—both vertically and horizontally—to control their interaction during earthquakes. The goal is to protect the infill panels, enhance global damping, and improve the overall seismic performance of the structure.

The experimental campaign consists of quasi‑static cyclic in‑plane tests on masonry‑infilled RC frames equipped with different configurations of deformable joints. By comparing the response of unstrengthened frames with those incorporating vertical and horizontal rubber joints, RUJOI evaluates the system’s ability to reduce or even eliminate infill damage, delay cracking, and increase energy dissipation. This direct testing approach provides essential insight into how deformable joints can transform the seismic behavior of traditionally brittle infilled RC systems.

Social Impact

Across many seismic regions, communities rely on RC buildings whose masonry infills are highly vulnerable to earthquake damage. Traditional strengthening methods can be invasive, expensive, or incompatible with occupied or heritage structures. RUJOI offers a non‑intrusive, cost‑effective, and architecturally neutral alternative that enhances safety while preserving building functionality and appearance.

By reducing infill damage and increasing structural damping, RUJOI contributes to greater seismic resilience, safer living environments, and faster post‑earthquake recovery. Its emphasis on affordability and simplicity makes it particularly valuable for regions where resources are limited and seismic risk is high.

Ultimately, RUJOI supports a future where reinforced concrete buildings are not only stronger, but smarter—capable of dissipating energy, protecting infills, and safeguarding communities during earthquakes.

Practical Implications

RUJOI aims to provide engineers with a simple, scalable, and construction‑friendly solution for improving the seismic resilience of RC buildings. Rubber joints are lightweight, easy to install, and compatible with both new construction and retrofitting scenarios. Their ability to modulate the infill–frame interaction helps prevent premature damage, reduces repair costs, and enhances the building’s overall deformation capacity. The project supports the development of practical design guidelines for integrating deformable joints into analytical and numerical models, enabling widespread adoption in engineering practice.

As-built condition

Vertical polyurethan joints