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Gantry Provides Powerful Lift for Epic Energy Project in Chile
08/28/2021
Engineered Rigging’s Chilean-based team is proud to have contributed to the success of the largest construction project in Chile by identifying the ideal rigging solution for the dismantling of a large-scale construction crane inside of a tunnel. The Alto Maipo Hydropower plant is being built in San José de Maipo, an area strategically located 50 km southeast of Santiago, the center of Chile’s power grid and home to 7 million people. With 44% of the country’s citizens living in Santiago, the Alto Maipo will be an important energy source for the city and surrounding areas. When completed, the facility will have a capacity of 530MW and is expected to generate approximately 2,350 Giga-watt hours (GWh) of electricity annually.
Construction of the run-of-the-river hydroelectric facility began in 2013 and is expected to be completed by year-end 2021. The project includes “the construction of two power plants, the Alfalfal II (264MW) and the Las Lajas (267MW), tunnels, four inverted siphons to cross streams, two forebays, and associated facilities, as well as 31 km of new access roads, four new bridges, and 17 km of 110/220kV power transmission lines.i The total investment of the Alto Maipo project is $3 billion dollars (US).ii
The Vienna-based European construction group Strabag was awarded a first partial contract for the construction of 74 km of tunnels and shafts, as well as caverns, excavations, civil works and the installation of hydro-mechanical structures. As construction of one of the tunnels of the Alfalfal II plant was nearing completion, STRABAG needed to dismantle and remove an overhead construction crane that weighed 80 tons, was 8 meters high and 9 meters long.
Given the massive size of the crane and restricted space for maneuvering inside of the tunnel, Engineered Rigging was consulted for a rigging solution. Our heavy lifting experts recommended the Enerpac Super Boom Lift (SBL) SBL500 hydraulic gantry system for the project. With a retracted height of just over 3 meters, the gantry easily fit under the construction crane. At its third-stage height of more than 8.5 meters, the gantry was then able to reach the full height of the crane.
With a capacity of 337 tons at its maximum height, the SBL500 safely supported the 80-ton crane while the crane’s legs were removed. The crane was then lowered and trolleyed out of the tunnel on the gantry. The gantry’s trolley capabilities allowed us to move the crane 23 meters through the tunnel to the exit. Once outside of the tunnel, the crane was safely dismantled at ground height.
STRABAG projected the dismantling of the crane would take 14 days to complete. However, the powerful SBL500 gantry was quickly assembled, and the crew was able to dismantle the crane in just seven days.
“Engineered Rigging opened its first office in South America in Santiago, Chile in 2020. The timing perfectly aligned with the dismantling of a crane in the Alto Maipo Hydropower project. We were able to provide a just-in-time rigging solution that included the rental of the SBL500 gantry,” shared John Kuka, Director of Business Development for Engineered Rigging.
ER and the company TECNOGRUAS joined forces to carry out this project successfully. Three weeks of planning were more than enough to coordinate the project, which included the study of the work area, logistics for transporting the heavy lifting equipment, and medical examinations so that our technical personnel were certified and authorized to work on the project. Five heavy lifting specialists completed the assembly, supervision, execution, and disassembly of the SBL500 equipment, along with the support of the staff of our client, STRABAG.
i NS Energy
ii BNAmericas
Drawing upon its extensive rental fleet, Engineered Rigging delivered four Strand Jack Systems, the Enerpac Smart Cylinder Control (SCC) and a laptop to the project site. Each system included one Enerpac HSL7006 Strand Jack, a strand guide, recoiler and SLPP7E hydraulic power unit mounted in a single frame (see Figure 1). In addition, Engineered Rigging conducted onsite training on the strand jack equipment and SCC System which allowed a single operator from the Army to simultaneously control the four systems, monitor the load on each jack and view the lift from a remote location which optimized safety. The SCC can control up to 60 strand jacks simultaneously, providing synchronous lifting and lowering operations and precise load control. The SCC also features user-defined alarms to trouble-shoot concerns during lifting and lowering operations.
To conduct the lift, the Army assembled a customized jack-up barge which was positioned over the gates (see photo below). The strand jacks were located on the deck, which was comprised of 12 modular pontoons with 80-foot jacking spuds. The four-strand jack cables were lowered down to the gates through moonpools on the jack-up barge.
Divers used a dredge pump and clamshell bucket to remove 80-years-worth of muck, clay and silt that had settled on the gates. Once cleared, they cut four access holes into each gate. The holes were large enough to secure the rigging which was attached to the strand jack load anchors. With a combined lifting capacity of 616,000 pounds, the strand jacks were more than able to break the suction from the underlying mud and lift each gate.
Once each gate was raised out of the river, the Army positioned a barge underneath it. The strand jacks then lowered the gate onto the barge to be transported to a nearby boat basin for recycling.
“The mission went better than expected with no major surprises thanks to the continuous input from our experienced employees and support from SPO’s excellent equipment manufacturers and rental supply base,” said St. Marys River Section Engineering Technician Theodore Clark, as reported in an Army news article.
As a US Army veteran and a history buff, this project was special for me. Whether it’s helping the Army Corps of Engineers retrieve some long-lost lock gates or another unique challenge, it’s a good day when our customers use our equipment to find success. If you need assistance identifying a heavy lifting solution, please contact me or any of our experts listed below.
