World’s longest pedestrian suspension bridge is a wonder of Portuguese engineering

“516 Arouca” has 516 meters span, hangs 175 meters high above the Paiva River and is the new tourist icon of the Municipality of Arouca

As of May 2nd, Paiva Walkways gets a new partner in attracting tourists to the Municipality of Arouca. Located 175 meters high above the Paiva River, with a span of 516 meters, 1.2 meters wide and consisting of 127 metal grid decks suspended by hangers and catenaries in steel cables, the “516 Arouca” is the longest pedestrian suspension bridge in the world. A new and exciting way of looking at the Paiva region, its walkways and all the natural beauty of the Arouca Geopark.karge

Located next to the Paiva Walkways, “516 Arouca” was built in order to consolidate the active tourism project in the Paiva valley, facilitating access to the Eastern area of ​​the municipality of Arouca.

For the mayor, Margarida Belém, “516 Arouca” is “a remarkable work of national engineering and will certainly be one of the most iconic works in the municipality of Arouca and in the country and that will surely become a landmark of modernity”. As with the Paiva Walkways, Margarida Belém is convinced that this bridge “will strengthen the economic and tourist competitiveness of this territory with the UNESCO recognition, enabling the creation of new experiences for the existing tour operators, as well as the creation of new jobs and businesses, particularly in the local tourism sector”. It will thus be an important “asset” for the revival of the economy and tourism at a local and regional level", she adds.

“This was a challenging and ambitious project and, above all, it is a project that makes us all very proud. It is a remarkable work for a municipality of our size, but equal to the locals and their capacity for resilience and struggle”, he affirms.

The “516 Arouca” is located in an area declared Natura 2000 Network and is located in the heart of Arouca UNESCO Global Geopark. From the structure you have a privileged and fascinating view of 2 of the 41 geosites that make up the geopark: Aguieiras Waterfall and the Paiva Gorge.

The story of an iconic project

The initiative to connect the two banks of the Paiva River arose in 2016 with the intention of the Municipality of Arouca to allow the crossing between Alvarenga and Canelas, thus complementing the network of walkways and facilitating access to them from Alvarenga, at the same time that enabled an elevated view of this waterfall.

‘Itecons - Institute for Research and Technological Development for Construction, Energy, Environment and Sustainability’ was hired, and its team was responsible for the design, analysis (numerical and experimental) and measurement. The local topography, the difficulty of access and the geological conditions forced a change in the initial plans leading to the creation of a bridge with a span between pillar axes of 516.5 meters and a height above the river of about 175 meters.

A true wonder of national engineering, “516 Arouca” began to be built in 2018 and was completed in the fall of 2020, being a work carried out during the time of the first woman to lead Arouca City Hall, Margarida Belém, with the monitoring and supervision carried out by the Planning and Works Division of the local authority. Now everyone is invited to walk the most exciting 516 meters of their lives, to live the experience of crossing a pedestrian suspension bridge over one of the wildest rivers in Europe, the Paiva, and to be a witness to one of the most iconic works of Portuguese engineering, while contemplating the stunning landscape located in the UNESCO Global Geopark.

Project Features and Safety

Since the beginning of the “516 Arouca” project, the visitor’s safety has been the promoters’ number one priority. Over several months, rigorous calculations were made on the action of the wind, with different speeds, on the bridge; cable resistance was extensively tested using numerical models and prototypes built in the laboratory; the various construction and anchoring solutions have also been meticulously studied.

Using a significant series of innovative techniques, all this numerical and laboratory work sought to find the ideal structure, ensuring the smallest detail of the safety of the crossing and at the same time guaranteeing adequate levels of comfort.

In the design of the suspension bridge project, the team of 'Itecons' immediately opted for a profile with a concave shape (formed by a set of various decks), not only for being similar, in aesthetic terms, to the Incas suspension bridges, are the ones that bear a close resemble to our imagination when thinking about pedestrian suspension bridges, but, above all, because it allowed to reduce the efforts and anchorages of the structure. The bridge design was set in order to guarantee that even in the unlikely event one of the cables breaks, the decks will remain connected with the others, allowing for the bridge’s safety.

The next step was to create the towers that allowed the elevation of the level and the angle of the main cables (catenary) to be raised, which suspend the decks by means of hangers. A solution that is already widely adopted in road bridges, such as the 25 de Abril bridge (Lisbon), and which has now been adopted in this project as well.

The balance of the towers is achieved through the continuity of the catenaries to the opposite sides of the central span, in the direction of the anchorage blocks. Finally, before proceeding to the construction of the project, it was necessary to find solutions for the horizontal forces, generated in particular by the action of the wind. Due to the natural difficulties of executing this project, ‘Itecons’ adopted a solution that consists of tilting the planes on which the overhead and overhead work, creating vertical and horizontal components that promote the balance of the entire structure. Angles of about 20º in relation to the vertical were also adopted.

LNEC - Laboratório Nacional de Engenharia Civil was another of the players in the construction of “516 Arouca”. Given the innovative character of this project, the Laboratório Nacional de Engenharia Civil implemented dynamic tests in a wind tunnel in order to study the forces generated for different speeds, with a view to validate the stability of the structure.

For Conduril - Engenharia SA, the construction company, the main challenges were focused on conceiving and implementing the hauling of the main cables, as well as the decks between the two banks of the Paiva river. All the material used in the construction was tested again and again, thus minimizing the risk of accidents or other damages as much as possible.

Throughout the construction process of the “516 Arouca”, there were several incidents. Some arising from normal work, others from occurrences during the execution of the project. The most challenging moments for 'Outside Works', a company specialised in vertical works, climbers and works at height, involved in the construction process, consisted of connecting the first rope from one bank to the other bank of the river (which forced to cross the Paiva swimming, in the middle of winter) and installing the first deck of the bridge.

Given that part of the infrastructure is built on the Paiva Walkways, it was necessary to coordinate the work with local security, ensuring that people passing by were always safe.

In the end, “516 Arouca” is made up of 127 decks with a metal grid flooring, each functioning as a kind of independent cell, which strengthens the feeling of safety and comfort for visitors. In order to maximize the crossing experience of “516 Arouca”, it is stipulated a limited number of people simultaneously on the bridge. It is intended that each visitor can enjoy the crossing in all its splendour, being able to observe the landscape, take photographs or film without an excess of tourists interfering in this idyllic setting.

516 Arouca’s Surroundings and Itinerary

Built in the middle of Arouca Geopark and embedded in the granite escarpments of the Paiva River, “516 Arouca” presents its visitors with a unique, breathtaking landscape with views over unforgettable landscapes. First of all, the natural beauty of one of the 41 geosites of the UNESCO Global Geopark, that of Aguieiras Cascade, formed by the waters of the Chieira stream that, next to the pedestrian suspension bridge, that flow towards the Paiva river’s waters. Or the Paiva Gorge, another geosite, which corresponds to a segment of Paiva where the bed becomes narrower and extends from the Alvarenga bridge to Vau. The steep rocky walls of this geosite are also rich in biodiversity, highlighting the lime green coloured patches that correspond to the lichen Acospora hilaris (Mediterranean climate indicator).

Built in the heart of the Natura 2000 Network, the watchful visitor can still observe several species, from the great short-toed snake eagle to the small two-tailed pasha. This is also the natural habitat for roebucks, European rabbits, red squirrels, otters, Iberian wolves, and common buzzards, and many more.

Throughout the surroundings of the pedestrian suspension bridge and the Paiva Walkways it is possible to find hundreds of animals, some of them at risk of extinction, who find in this natural landscape a perfect refuge, as well as a vast and rich flora that gives the region, in any time of the year, an added beauty.

A setting full of charms where the well-known Paiva Walkways are located, the recreational and leisure areas of Areinho and Vau, as well as whitewater sports, an additional attraction of the Paiva River.

Prices, Opening Hours, Access, and other relevant information

To reach “516 Arouca” you have two entrances to choose from. One is through Areinho river beach, walking part of the Paiva Walkways and accessing the pedestrian suspension bridge. If you want a less physically demanding route, you must drive to the Alvarenga parish and, from the Market’s parks or the one at the football pitch, you can do the route on foot, through old paths that cross fields and picturesque places like Vila and Chieira.

The crossing of the longest pedestrian suspension bridge can be done in both directions (round trip) or one way, proceeding to the Paiva Walkways or to the historic centre of Alvarenga, depending on the entry point to the bridge.

When purchasing access tickets, a time slot must be chosen to do the visit. Visitors must be at the meeting point, set for this purpose, 15 minutes before the scheduled time. The visit must start at the appointed time.

Limited to a maximum of 50 visitors simultaneously, the visit to “516 Arouca” will always be accompanied by a guide and lasts approximately 1 hour and 30 minutes. The guide will meet the visitors at the location identified for that purpose and will accompany the group to the entrance of the pedestrian suspension bridge. There, there will be a briefing about the infrastructure and landscape and information will be given regarding the rules and care to be taken during the visit. Visits are available in Portuguese and English.

The ticket to access the “516 Arouca” is 12€ and includes admission to the Paiva Walkways. Access to children under the age of 6 is prohibited and for the remaining age groups there are specific discounts, namely for children, seniors, and groups.

Family Pack Prices:

• Family Pack A (2 adults + 1 child) = 30€
• Family Pack B (2 adults + 2 children) = 40€
• Family Pack C (2 adults + 3 or more children) = Family Pack B + 5€ for each additional child

For the residents of Arouca who have a valid Walkways’ resident card, admission is free, but is mandatory to pre-book on the bridge's website: https://516arouca.pt/. For residents who issue a new card, this has a cost of 5€, being valid for 3 years.

The “516 Arouca” is an inclusive infrastructure. In order for a unique and quality visit to be provided, a prior contact must be made to the Interactive Tourism Store of Arouca Geopark, in order to safeguard the conditions necessary to provide a unique and complete experience.