Laguna Garzón Bridge: Connecting Two Shores with a Circular Deck

Laguna Garzón lies on Uruguay’s Atlantic coast, where the departments of Maldonado and Rocha meet. The new bridge crosses the lagoon’s southern end near its outlet to the sea, connecting the two sections of Route 10. Before construction, vehicles and people used a ferry operated by the Ministry of Transport and Public Works’ hydrographic department, with service limited to daylight hours. A more dependable crossing became a project promoted jointly by local governments and tourism developers.

The ministry and Las Garzas Blancas, a company led by Argentine businessman Eduardo Costantini, jointly financed the project. The inauguration report put total investment at about US$12 million, with the private company covering roughly 80 percent. The public authorities separately reported US$1.8 million invested in connections between the bridge and the roads. These were the investment figures announced at the time.

References: [1] [5]

A crossing had long been controversial. Supporters in Rocha sought better access to encourage tourism, employment and services. Opponents feared disturbance to wetlands, increased coastal traffic and changes to a quiet residential environment. Interviews in the government magazine Políticas in 2012 show that the debate centered on how waterfront land would be developed, extending beyond the bridge’s appearance.

Rafael Viñoly’s circular proposal introduced turning and opportunities to stop and view the scenery into a vehicle crossing. However, the 2012 report still described a floating-bridge concept using wood, aluminum and fiber materials, explicitly stating that technical details remained under study. The bridge completed in 2015 was a concrete structure supported on piles and columns. The floating arrangement in early reports does not describe the finished bridge.

References: [2] [3] [4]

The completed bridge has a central ring with a radius of 51.5 meters and approximately 323 meters of circular deck, connected at each end by a straight section of about 46 meters. Vehicles travel along the two sides of the ring between opposite entrances and exits. The roadway is five meters wide, with concrete crash barriers on both sides. Pedestrian walkways extend beyond the barriers, giving walkers access to views over the water inside the ring and the landscape outside it.

The circular route requires drivers to turn, and slowing traffic was an explicit design aim. Rafael Viñoly Architects provided the architectural design, CYD Ingenieros the structural engineering and SACEEM the construction. The bridge’s recognizable form comes from its route in plan, while precisely connected beams, deck and foundations carry the vehicle and pedestrian loads.

References: [1] [3] [4]

SACEEM’s completion report dates the start of construction to September 2014. The central ring uses precast, post-tensioned trough-shaped elements spanning about 20 meters. Once installed, an upper deck slab was cast in place to form single-cell box girders. Multi-cell box girders at the entrances and branching sections were cast on site. Different construction methods accommodated the geometry of the circle and its widening approaches.

The curved structure complicated the placement and stressing of prestressing tendons. Transporting and lifting elements weighing about 70 tonnes was another construction challenge. The contractor reported approximately 3,500 cubic meters of concrete, 450 tonnes of steel and 40,000 meters of post-tensioning tendons. The tendon length is a materials quantity, separate from the length of the bridge deck.

References: [4]

The construction environmental-management plan of May 2014 required a temporary fill platform extending from the west bank. After installing the piles, columns and beams on that half, construction would move to the eastern side. A water opening at least 90 meters wide had to remain throughout the stages. After use, platform materials were to become fill for the approach embankments. Parts left by an earlier project that obstructed the new bridge were also scheduled for removal.

The plan required water sampling before, during and after construction, increasing to fortnightly sampling during piling and cofferdam work. It also required restoration of banks, clearance of waterways and replanting. Environmental management covered temporary works and site clearance as well as the permanent crossing. These provisions establish management requirements; the plan alone does not demonstrate that every subsequent indicator met its target.

References: [5]

On 22 December 2015, Transport and Public Works Minister Víctor Rossi, the tourism minister and officials from both departments attended the inauguration in wind and rain. The opening gave the two shores a road connection independent of the former ferry schedule. Its pedestrian space also made the crossing a place for viewing the lagoon.

Alongside the project, the section of Route 10 from José Ignacio to its junction with Route 9 in Rocha came under local jurisdiction. At the ceremony Rossi emphasized coordination between the bridge and Rocha’s land-management plan. Government and investors expected tourism growth; control of traffic, waterfront construction and ecological pressure continued to depend on road management and land-use arrangements, beyond the circular design itself.

References: [1] [2] [3]