Visible Reinforcement: Kajima’s Hysteretic Seismic Damper Retrofit at ICC Kyoto

The Kyoto International Conference Center (ICC Kyoto) retrofit project, designed by Kajima Corporation in Kyoto, has improved seismic resilience and structural transparency through the integration of a visible hysteretic damper within its underground parking structure. Implemented in response to the seismic policy shift after the 1995 Great Hanshin Earthquake, the intervention enhances inspection access and demonstrates Kajima’s Seismic Isolation System (KSI) technology. Completed in the annexes of the original 1966 brutalist complex by Sachio Otani, the project reflects Japan’s broader engineering approach, emphasizing public awareness and structural adaptability.

The Kyoto International Conference Center, designed by Sachio Otani and completed in 1966, is a key work of Japanese modernist architecture. Located in Kyoto’s Takaragaike Park, the complex gained international attention for hosting the Kyoto Protocol negotiations in 1997. Although the main brutalist volume remains structurally intact, the annexes have been retrofitted to meet the revised seismic standards introduced nationwide after the Hanshin disaster.

Kajima Corporation, a major construction and civil engineering firm in Japan, directed the retrofit. A red-painted steel hysteretic damper was installed and left intentionally visible in the underground parking structure. This damper does not bear vertical gravity loads—those are supported by surrounding continuous reinforced-concrete columns. It functions exclusively under seismic motion, dissipating energy through plastic deformation to reduce lateral force transmission to the structural frame.

Exposing the damper aligns with a national architectural policy of seismic legibility, allowing engineers, inspectors, and the public to observe seismic mitigation technologies in place. This visible integration supports long-term maintenance and reinforces civic trust in structural safety. The device is not part of a base isolation system and does not include elastomeric bearings or decoupling mechanisms. It belongs instead to a category of passive vibration control systems mounted within the structural frame.

Kajima’s proprietary KSI system incorporates such dampers in retrofit applications for public and institutional buildings. While base isolators are typically installed between superstructure and foundation to minimize ground motion transfer, dampers like this are integrated within the building frame to absorb seismic energy. All infrastructure connections between structure and ground—including piping and cabling—were fitted with flexible joints to ensure performance continuity during movement.

The placement of this seismic damper within a utilitarian space like a parking garage underscores the possibility of making structural performance visible without compromising architectural intent. Kajima’s retrofit maintains the integrity of Otani’s original design while embedding a high-performance seismic mitigation system. The project exemplifies Japan’s long-standing commitment to structural openness, preventative engineering, and long-term seismic adaptation.