Costa Rican outing for Aquajet hydrodemolition equipment
28 July 2009
Two Aqua Cutter robots from Aquajet were used by Spanish hydrodemolition specialist Hidrodem to remove more than 800 cubic metres (28,250 cubic feet) over more than 6,000 square metres (64 583 square feet) on more than 10 bridges in Costa Rica. The bridges required upgrading as part of the San Jose - Caldera highway development. The new 77.5 km (48 mile) highway will reduce travel time between the Central Valley and the Central Pacific Coats by at least 30 minutes and will be use by more than 81,000 vehicles every day.
The existing bridges' concrete slabs required thickening to accept this increased traffic density and it was for this work that the Aquajet units were deployed, removing concrete to an average depth of 10 cm (4 in). According to Hidrodem, the section between San Jose and Caldera posed challenges in organisational and management skills and logistics.
On the busiest bridge, Puente de Escazu, the concrete slab was tackled in three 7.5 m (24.5 ft) strips and another, the Rio Jesus Maria Bridge was found to have a concrete thickness below the minimum standard of 15 cm (6 in). Following hydrodemolition of slab, concrete was poured to a new standard thickness of 17 cm (6.5 in) that with rebar provided a total thickness of 22 cm (8.5 in) to meet the new standard. The use of hydrodemolition allowed the completion of work to the tight project schedules while at the same time allowing the bridges to remain open while work was ongoing.