Modular Bridge General Viejo, Costa Rica
Facts and Figures:
Place/Country: Río General Viejo, Costa Rica
Completion: 2021
Project type: Modular Steel Bridge (Truss-type)
Client: CONAVI, Constructora MECO
Description:
In its long history Waagner-Biro has supplied more than 100 km of modular steel bridges worldwide. The longest modular bridge is Calaba Bridge in the Philippines, a multi-span truss bridge reaching 900m. In the spring of 2021, Waagner-Biro’s longest single-span and double-lane modular steel bridge to date was opened over the General Viejo River (located at General Viejo de Perez Zeledón) in Costa Rica. It is situated on the National Route 321.
The completion of the bridge fulfilled a promise made by the President of the Republic, Carlos Alvarado, and the Minister of Public Works and Transport, Rodolfo Mendez Mata, to replace an old structure which had collapsed following a tropical storm in 2017 with a new and more robust one. Waagner-Biro won the contract for the design and supply of the new permanent steel bridge.
As the river is prone to flooding during the rainy season, it was decided for the new bridge to be installed at a higher ground level, enabling people to cross the bridge at any time and go about their business regardless of any floods swelling the riverbed.
The new bridge is 121.5 metres long. The structure is made of hot-dip galvanised steel and consists of 27 modules, each 4.5 metres long. An 8-metre wide concrete slab is placed on top of the cross girders and stringers (as part of the deck). Each lane of the two available lanes is 3.68 metres wide; the asphalt layer on the concrete slab serves as road surface (5 cm thick).
The substructure consists of reinforced concrete wall-type bastions, measuring 12 metres high by 8.8 metres wide and 8.8 metres high by 8.8 metres wide, respectively, due to the difference in level between each end of the riverbed. The crossing is located a few metres from where the old bridge used to be.
In order to benefit the many people who walk through the area, there is a 1.5 metre wide walkway, attached externally to the truss, with pedestrian railings and a steel floor.
In the second half of 2020, construction of the new bridge commenced. Waagner-Biro collaborated with Constructora Meco on the assembly and launching of the 121.5m pre-fabricated modular steel bridge. Providing on-site supervision, Waagner-Biro’s role was to ensure that the bridge was built rapidly, safely and efficiently. Construction was not without its challenges: The area available for assembly of the launching nose and truss bridge was limited and had to be filled up. Installation took place in the midst of the Covid-19 pandemic and yet finished according to schedule.
Up to the time of the collapse of the old bridge, some 4,000 vehicles had passed over the site every day. The communities of General Viejo, Los Chiles, El Carmen, Santa Margarita, Rivas and Barrio Sinaí, as well as Peñas Blancas and Barrio los Pinos, among others, are among the beneficiaries of this project, since the bridge reconnects all of these local communities and re-enables vital access to social amenities.
