Italian civil engineering company Mavi has deployed its Enerpac EVO multi-point synchronous lifting system for bridge bearing retrofit work on the Savio viaduct in the region of Emilia-Romagna, Italy.
The EVO system, which operated 12 Enerpac hydraulic cylinders, is allowing Mavi to safely install new seismic isolators by synchronously lifting, holding and then lowering the bridge decks.
Located within a narrow, winding valley, retrofitting the 1,890 m-long viaduct involves replacing all existing bearings with unidirectional and multidirectional seismic isolators designed and manufactured by Mavi, along with friction pendulum isolators fabricated and supplied by a different Italian company.
Working between different height piers, Mavi has deployed the Enerpac EVO and 600-tonne capacity cylinders to simultaneously raise the two bridge deck ends resting on each pier, providing access to the new bridge bearings. Loads at the end of each span range from 1,224 tonnes to 6,300 tonnes for two of the piers, with 6,600 tonnes at a separate pier.
“Lifting the bridge decks is a precise operation that requires careful and accurate control,” said a Mavi spokesperson. “The combination of Enerpac’s EVO synchronous lifting system and high-capacity cylinders means we are able to confidently lift loads that in some situations exceed 6,000 tonnes.”
Enerpac’s EVO system combines high-pressure hydraulics with a PLC-system to monitor and control precise movement and positioning of heavy loads, whereby a single device can control the entire lifting operation – without the need for manual monitoring.
For the Savio viaduct project, the Enerpac EVO control unit allows the 12 cylinders to be operated at different pressures and constant volumetric rate, ensuring controlled lifts without inducing flexural-torsional stresses to the bridge deck. Through the EVO, the pump can read stroke sensors, which allows the computer to read precisely how high the deck has been lifted, along with controlling the pressure in each jacking cylinder to guarantee a synchronous lift.
HLPFI reported in October that an Enerpac strand jack had been used for maintenance of a cable car in Toulouse, France.
