Redefining resilience - From past to today and future conditions
Resilience is about designing systems and teaching them how to react to shock events, i.e., what time of anticipation is and the time for recovery and adaptation. How the systems respond and possibly adapt depends on their resilience, which can range from adaptive resilience to recovery-time resilience (i.e. returning to the state or taking longer to recover) to ultimate failure, meaning complete lack / failure of resilience.
Etymology of resilience: Recovery and adaptation
The dictionary defines resilience as 'the ability to recover from difficulties or disturbances'. It originates from the Latin term 'resilio', meaning 'to return to a state' or 'to spring back'.
In the 19th century, resiliency was defined as the capacity of specific materials to withstand specific disturbances, and it was used in engineering to enhance the resilience of buildings and materials.
In the 20th century, researchers studied many forms of resiliency and found that a framework could apply to many scenarios and subjects, such as resilience in connection to psychology, risk exposure and stability in ecological systems, designing systems to withstand certain events, among many others.
Resilience in construction and engineering
The four Rs of resilience are:
- Robustness: how to withstand events without suffering loss of function
- Resourcefulness: how to identify resources and problems
- Redundancy: how to cope with various paths to enable continued function
- Rapidity: how to set priorities to restore in time
In engineering and construction, resilience is the ability to absorb or prevent damage without complete failure. It is an objective of design, maintenance and restoration for buildings, infrastructure and communities.
The USGBC and LEED green building certification define resilience as "the ability to prepare and plan for, absorb, recover from and more successfully adapt to adverse events". 
What should you know about resilience?
When we talk about resilience in buildings today, we refer to climate-related events (climate change, extreme weather disasters, etc.). All buildings, regardless of location, are subjected to the conditions and forces imposed by the natural environment. The concept of resilience is gaining attention for its durability in withstanding climate-related events, and at the same time, redundancy is being designed to protect occupants when critical building systems fail.
Design professionals and building codes address and strengthen buildings' resiliency to a basic level through engineering and architectural approaches, using, for example, material durability and the ability to withstand, including absorption effects.
Resiliency through adaptability and flexibility
A resilient building changes over time and serves multiple functions. Designers and owners should recognise that a building’s life cycle extends beyond its initial use and plan for potential adaptations. Health-related events, such as the last pandemic, highlighted the flexibility of buildings in meeting spatial needs for diversity and planning, and the need to assess work efficiency through remote work patterns, including the new digital environments in people's lives.
Difference between sustainability and resiliency
Sustainability focuses on meeting the needs of the present without compromising the ability of future generations to meet their needs. Resilience ensures that even during unforeseen events, it does not fail catastrophically and continues operations. Resilience planning allows communities, infrastructures and systems to bounce back after events.
Resiliency through repair and reuse (including many other Rs) is a relatively new and rapidly developing building phenomenon. Resilient design and architecture find ways to extend the use of buildings. At a very high level, the resilience plan for the unexpected could, for example, involve repairing a building after an unforeseen event. This also embodies the idea of a circular economy, allowing buildings, for example, to be disassembled and reused in future projects after unforeseen events.
Designing for resilience means accounting for both current and future conditions
Resilience is about being prepared and mitigating negative impacts. However, we can be even more holistically prepared to support, adapt and maintain buildings. It is a way of considering a building's broader impact in the event of unexpected events. As unforeseen events become more frequent, unpredictable, and intense, buildings must still adapt to protect lives, systems, and environments. Resilience in buildings is no longer an option; it is a necessity that demands action from all involved, including investors, architects, engineers, and others. 
