Designing infrastructure that lasts

Many of us have heard the remarkable fact about Paris’ famous Eiffel Tower that it was only designed to last for 20 years – and yet some 130 years on, it’s still standing. Sometimes long-lasting infrastructure does happen by a happy chance, but in creating the cities of the future, it’s clear we’re going to have to think more outside of the box. Here are some existing projects that show how modern-day equivalents of the Eiffel Tower could be achieved by design.

Building a world-class airport… on mud?

Designed to be one of the largest and most futuristic airports in the world, planners involved in the ongoing construction of the New Mexico City airport had one major challenge to overcome – the area is sinking. Aside from the site being located on an area with over 30 meters-deep clay mud, as well as subject to significant seismic forces, many existing structures in the region are subject to 7 to 10 centimeters of sinking every single year. When you’re planning an airport, where exceptionally large and heavy vehicles will be making use of the infrastructure continuously, it was clear that ordinary solutions just weren’t going to be enough.

soil reinforcement

Simply getting construction vehicles onto site posed a problem!

The solution turned out to be the use of PRS Geocell Technology – a cellular confinement system created from a durable material known as Neoloy. These honeycomb-like cells are delivered to site flat, stretched out and filled in with whatever local materials are available. In this case, the local material was a lightweight volcanic rock called ‘Tezontle’, reducing the necessary construction time. In addition, the geocell solution could be laid under all weather conditions, cutting a full year off the previously expected construction time.

soil reinforcement

Geocell layer visible before being filled in

This solution worked so well that asphalt thickness could be reduced by 30%, resulting in 60% less weight – essentially allowing the structure above to ‘float’ on the soft clay soil below. In fact, one year after installation zero settlement had occurred – a phenomenon unheard of in the area!

Concrete that bends under pressure

It may be our go-to construction material of choice around the globe, but there are still a lot of issues with concrete. While it’s certainly tough, it’s also very brittle. It can bear an enormous amount of weight – hence its popularity in massive structures like skyscrapers – but has very little ability to bend or deform under unusual forces, even with steel reinforcement in place. In areas where earthquakes are a real possibility, this has long posed a very real problem, but that might be set to change!

In a joint venture by researchers from the University of Michigan and laboratories across the globe, it has been shown that concrete can be made more ‘ductile’, or able to bend under pressure without giving way. The inspiration for the new material, called engineered cementitious composite (or ECC for short) has a pretty pleasing source too – mother of pearl or nacre. Largely composed from plates of calcium carbonite, a very brittle material, these shells are still able to withstand a great deal of pressure from predators like otters actively trying to break them.

The reason for the increased flexibility is a natural polymer which acts as a kind of mortar in-between the brittle plates. Apply this principle to concrete, and you have a substance with 300 to 500 times more tensile strain capacity than normal concrete. This has massive potential in the global construction industry, not just in designing safer buildings, but in making more long-lasting repairs to existing crumbling concrete structures like pavements and roads.

Durable meets sustainable

One of the biggest concerns in creating infrastructure that lasts is how to make it more sustainable too. In Masdar City in the United Arab Emirates, Abu Dhabi-based company Masdar aims to show how it can be done. This ambitious project includes several notable objectives – including the repurposing of waste, placing buildings strategically to make use of the prevailing winds for cooling, incorporation of low-carbon transport and paths for cyclists and pedestrians, smart shading and even a 10MW solar photovoltaic power plant.

While it remains to be seen how successful this project will be, it highlights a very critical point when it comes to combining durable infrastructure with more sustainable building techniques – namely that buildings need to start working together and solving bigger problems collectively. Creating the infrastructure of the future will mean collaborating not just with each other, but also with the environment to craft innovative solutions.