"In Engineering, bridges are considered works of art and every work of art has its authors."
“In Engineering, bridges are considered works of art and every work of art has its authors.” This sentence, by the head of Itecons, perfectly sums up all the spirit present in the construction of the 516 Arouca, where dozens of specialists, from the most diverse areas – from the project to the last detail – put their hands to work to build this true piece of metallic art, the largest pedestrian suspension bridge in the world.
516 Arouca: those responsible for the work
Arouca City Council
Ownership of 516 Arouca. Emblematic engineering infrastructure, built under the presidency of Margarida Belém and with follow-up, supervision and inspection by the Municipality’s Planning and Works Division.
Institute for Research and Technological Development for Construction, Energy, Environment and Sustainability – responsible for design, analysis (numerical and experimental), dimensioning and technical support during construction.
National Civil Engineering Laboratory – responsible for tests in the wind tunnel and on site to verify the safety of 516 Arouca.
Engenharia, S.A. – Portuguese company dedicated to the execution of Civil Engineering and Public Works. Responsible for building the bridge. For this purpose, it subcontracted two partner companies:
Cordoaria Oliveira Sá
Responsible for the production and installation of the entire cable system that makes up and supports the bridge.
Specializing in vertical work, it was the company responsible for work at heights at 516 Arouca.
The experience of being part of a unique project
Working on the construction of the largest suspended pedestrian bridge in the world is a once-in-a-lifetime opportunity for any professional and/or company in the area. To record and share a little of this experience, the entities involved in this unique work, and those responsible recalled some remarkable details of the process.
For the Municipality of Arouca, owner and main responsible for 516 Arouca, the construction of this work was a unique and enriching opportunity. An ambitious project loaded with responsibility, but also a great honor and pride.
This pride is also shared by the design team of IteCons, as the size and complexity of the work was a great challenge.
In the case of LNEC, the opportunity was also received with enthusiasm and highlights the harmony between the Municipality of Arouca, the design team and the LNEC team, which allowed for an exemplary work development.
For Conduril, everything is summed up in one word: pride.
Since this was a unique project, none of those involved had much specific experience in this type of work. Oliveira e Sá highlighted the union of stakeholders as one of the most positive points. Despite the challenges and difficulties faced on the ground, mutual help and unconditional collaboration were crucial.
And Outside Works says that it was a challenging experience that became a reference and that it will forever remain in the memory of all the climbers who were there, as well as in the history of the company itself.
The Challenges of Building a 516-meter Pedestrian Bridge
As an innovative work, and considering all the difficulties that have occurred since its inception, the biggest challenge for the municipality was the need for constant adaptation and the conciliation of all the parties involved.
In LNEC’s area of competence, the great challenge was to implement dynamic wind tunnel tests in the lateral displacement mode (“swing”). According to the laboratory, suspension bridges most subject to tests in wind tunnels are usually road bridges, in which the possible movements do not include lateral displacements.
Adapting the model suspension so that it could move like a “swing”, keeping all the necessary characteristics, was the biggest challenge. However, this does not mean that the tests performed on the real bridge were any easier. This phase involved a wide range of instrumentation and a group of volunteers who made themselves available, according to pre-established procedures, to “load” the bridge from “dawn to dusk”.
Before LNEC could start thinking about trials, IteCons had its own challenges, which had to be overcome so that trials could be carried out later. It took many hours to develop numerical, static and dynamic models, necessary to simulate the behavior of the bridge when subjected to various actions.
Designing and implementing the launching of the main cables and decks between the two banks was, for Conduril, the greatest challenge of all.
From the many hours spent several meters above the ground, putting each piece of the bridge in place, Outside Works added some challenges. The process of passing the first rope was especially remarkable. Having to swim across River Paiva, in the middle of winter, to be able to take the end of the rope to the other bank, to assemble the cable car that made it possible to mechanize the work and move loads from one side to the other, was a very remarkable challenge. But there were others.
As part of the infrastructure was built over the Paiva Walkways, the work had to be coordinated with local security and the passage of people had to be monitored. Even above, there were moving pieces and until the first board was assembled, a lot of work had been done. With more or less adaptations to adjust to the construction method, the bridge had to meet all safety and stability criteria. This was effectively accomplished.
The impact of this project on the
development and promotion of Arouca
For the Municipality of Arouca, as with other major works around the world, the suspension bridge will be a reference project, a different equipment that will certainly attract a diverse audience and attention at another level, namely a more technical audience, which, in addition to the interest in the region's natural beauties, will also come from the curiosity concerning the project and the work.
IteCons believes that 516 Arouca will work as the Paiva Walkways, placing Arouca on the tourist map. In this way, the pedestrian bridge should bring even more visibility to the region.
Conduril also believes that this “work of art” will reinforce the dynamism and development of Arouca, attract countless people and investors and increase the region's tourism potential.
For Outside Works, the bridge ends up giving added value to the region, along with the also pioneers, Paiva Walkways, taking the name of Arouca even further and helping local tourism. The level of expectation is high.
The complexity of 516 Arouca
Building what has become the largest pedestrian suspension bridge in the world, as expected, was a task of enormous complexity, a very ambitious project, for the scale of the Municipality of Arouca. However, 516 Arouca will be a reference, not only for the originality of the project, or the specifics of the work, but also for the ambition and courage of a relatively small municipality to manage to build an extremely beautiful bridge that is also a world record.
For Conduril, this project was, without a doubt, one of the most difficult and demanding projects ever carried out by the company.
Oliveira Sá recognizes the high level of complexity. However, it recalls a detail that may go unnoticed by many of the users who will be crossing the bridge, but that makes all the difference. “The cables prepared for the composition of the bridge were made from several wires wrapped around a core.
In this way, the work was coherent with the concept of the designers, who designed an 'Inca' style bridge. By using the system of several cords, they reproduced the technique of ancient hemp ropes that, between the 15th and 16th centuries, were wound almost manually, with the aid of a tourniquet.”
According to Outside Works, this was a work that required a highly multidisciplinary team, with a huge and constant adaptability. A hard project where the complexity concerned knowing how to do the “little ant” work until completing nearly 90 tons, in the middle of a valley, between two pillars separated by 516 meters, which required a lot of planning, preparation and resources.
There are many features that make the 516 Arouca a unique bridge. However, for IteCons, there is no doubt that the most differentiating element is its span, as it is the largest in the world.
However, its pillars in V, or inverted A, are also worth mentioning, which solve the problem of vertical and horizontal actions in a single pair of catenaries. The solution is not exclusive, but most suspension grid bridges instead use horizontal cables between the bridge and the banks to make the horizontal locking.
The length of the bridge and the surrounding landscape, based on the adventurous spirit that each user evokes, are, for Conduril, the main differentiated elements of this work of art.
For Outside Works, the 516 Arouca is an icon of engineering and construction, an unprecedented project that arouses special interest, both from the population and from professionals and companies.
The largest suspended pedestrian bridge in the world surprises and fascinates. It's more than an unforgettable experience.