How do you build a viaduct across a ravine and beside a mountain while minimising environmental impact? With a cable car and great precision.
The Viaduct V3 in Brazil could barely be harder to access as a construction site. It sits on a horizontal curve of 500m in length, with steep slope, crossing a valley 65m below. Tasked with building this as sustainably as possible as it passes through the Serra do Mar State Park, Engecorps Engenharia took a remarkable approach.
What is the Viaduct V3?
Viaduct V3 is part of the strategic programme to expand the Tamoios Highway connecting the coastal plain and Port of São Sebastião, to the plateau in the Vale do Paraíba region of Brazil. The road is used by 22 million people each year and its expansion is a vital step to improving both capacity and safety.
The viaduct itself has five spans and four central supports, in addition to the abutments, with a total length of 310m and a constant width of 12.6m. The central span measures 125m as it passes above the valley and along the mountainside.
The incredible steps to build it, however, are what really set it apart.
Cable Crane and onsite materials
Accessing the site was complicated, especially with the centre of the span sitting between a mountainside and deep valley in the middle of a state park. The engineers involved decided they could avoid damaging the park with service roads by deploying a cable car style crane in stead.
The innovative ‘Cable Crane’ equipment was built with a load capacity of 20 tons and covered the entire length of the work site – spanning almost 400m between its support towers. This provided a unique level of access for materials from above with minimal footprint on the ground.
That minimal footprint was important. The state park is a native forest, where a vegetation suppression of about 40,000m² was expected. Avoiding that damage saw the project win the 2017 ECO Sustainability Award from the American Chamber of Commerce.
Additionally, with tunnels excavated as part of the wider highway programme, the Viaduct was built with concrete made from the excavated stone. That significantly reduced the need to import materials long distances onto site, which helps to reduce carbon from transport. It also helped speed ease logistical risk and reduce timeframes for construction.
This project is one of three winning Outstanding Projects of the Year as assessed by a panel of FIDIC experts. It was nominated by Engecorps Engenharia, part of Grupo TYPSA.
Cable crane spanning the length of the viaduct during construction.
