On March 11, 2011, tsunami waves triggered by an 8.9-magnitude earthquake – the strongest in Japan for 140 years – slammed into Sendai Airport in northeastern Japan. In a terrifying scene viewed by millions online, waves up to 33 feet high engulfed the airport, reaching the second level of the passenger terminal where some 1,300 people were stranded for two days before being rescued.

On April 22, 2011, the most powerful tornado to hit St. Louis, Missouri, in nearly half a century touched down near the original 1956 terminal at Lambert-St. Louis International Airport.

The building remained structurally intact, but 135 mph winds had blown the glass out of many of the main terminal’s windows and swept a large section of roof off a concourse.

Designing for Disasters

Whether it’s earthquakes, tornadoes, tragic floods that devastated parts of China and Thailand, Hurricane Irene closing airports along the US eastern seaboard or the volcanic eruption in Iceland, the world is experiencing an alarming number of natural disasters at the moment and airport officials are paying attention.

This may sound obvious, but one of the first things design teams must do today is identify what disasters an airport might need protecting against and decide how to minimise the risks for each.

There are many levels of preparedness and multiple strategies – some of which may conflict – for each disaster. But, the good news is that if we consider these threats early in the planning process and integrate our responses into the design, buildings with disaster-resistant technologies will have exceptional long-term value. And these elements do not take significantly longer to construct and do not have to cost more.

Sendai Earthquake and Tsunami

HOK designed Sendai Airport with Japanese firm Nikken Sekkei. Though this airport was not planned to withstand a tsunami, it was able to perform well through two near-simultaneous natural disasters. The damage to the terminal was mostly caused by debris from the flooding.

How was this possible? With Japan sitting in one of the world’s most active seismic areas, the level of earthquake preparation is extremely high. Building codes have stringent seismic design requirements and any additional costs for stabilisation are already built into project budgets.

“Integrated design” is a buzzword in our profession. In Japan, it’s just part of the design process. In our experience working on three different-sized airports in Japan – Sendai Airport, Central Japan International Airport (Nagoya) and Kitakyushu Airport – the integration of architecture with structural and mechanical systems enabled us to create stable, welcoming and architecturally elegant buildings.

In the case of Sendai’s terminal, the solution that emerged from the strict building codes, featured cluster columns that provide a stable footprint for the 475,000-square-foot structure.

The mechanical system fits into the void space between the four columns that make up each cluster. These “umbrella” columns raise up to support the terminal roof and its series of undulating trusses and help distribute the structural load through the terminal, stabilising the building.

When the tsunami waves hit Sendai Airport, most passengers were above the submerged first level, since the design places most passengers on the second level of the terminal.

The design orients the terminal so the short side faces the ocean. As a result, less water was able to collect and exert force against the building.

The team oriented the terminal this way because the prevailing winds dictated that the runway be east-west. But, as with placing passenger activity on the second level, it’s a lesson for airports planning a terminal near a large body of water.