CRITICAL INFRASTRUCTURE

Base isolation remains the gold standard for excellent seismic performance, but it is not always practical or achievable within real-world project constraints.

Projects may encounter challenges such as:

• Cost Pressure: Additional structural, foundation, and construction costs can exceed available budgets.
• Site Limitations:  Poor ground conditions, flood requirements, or existing infrastructure can complicate isolation systems. 
• Architectural Constraints: Separation gaps, movement allowances, and service detailing may conflict with project requirements.
• Programme Complexity: Isolation systems can increase procurement coordination, consenting complexity, and construction sequencing risk.
• Retrofit Challenges: Introducing isolation into existing operation facilities is often highly disruptive. 
  

For many projects, the challenge is not whether resilience is important - it is how to achieve meaningful performance improvement within practical delivery constraints.

In response to these challenges, industry has sought ways to control residual drift within the structure itself. A common strategy is pairing supplemental damping systems with a separate structural system intended to provide restoring force.

Examples include:

• Viscous dampers with moment frames
• Rocking shear walls with post-tensioning
• Supplemental damping with braced frames

While effective, these systems often introduce additional project complexity because performance depends on the interaction between multiple structural mechanisms. 

• More complex analysis and modelling

• Increased detailing and coordination requirements

• Greater interface management between systems

• Additional architectural and construction integration demands

• More complicated retrofit implementation

• Increased procurement and sequencing complexity

By combining energy dissipation and re-centering into one compact system, Tectonus offers an alternative intended to minimize some of these headaches.  

Base isolation was never going to work for the client economically-speaking. But with memories of the Christchurch Earthquakes still recent, they were open to achieving high levels of resilience whilst staying within their existing budget.  

Beca engineers in Christchurch challenged themselves to find a resilient solution that would cost no more than a conventional system. This led them to Tectonus and a collaborative design process that resulted in a design that met the client's objective.  

The solution featured tension and compression braces with RSFJ dampers, as well as concrete shear walls with Tectonus hold downs. The following results were achieved: 

• Fully self-centering behaviour
• Removal of two shearwalls and multiple brace bays
• Estimated 40% reduction in embodied carbon
• Winner - World Architectural Festival (Higher Education, '24).