Enerpac Strand Jacks Lifting the Songdo Cable-Stayed Bridge Pylons Enerpac Strand Jacks
Problem: Lifting and positioning two 2,000 ton cable-stayed bridge pylons into place. To prevent counter-balance issues, it was critical to erect both pylon sections simultaneously and within a very tight tolerance. Any counter-balance issues would have created a lopsided load and put undue stress on the center pillar. The lack of a good footprint and the approximately 100 meter lifting height made the lift almost impossible for two cranes or another lifting solution. The need to lift from the central point of the structure required a high capacity lifting solution that could raise both sections simultaneously from a central point.
Solution: Four HSL8500 strand jacks were installed on top of a temporary bent tower and simultaneously lifted both pylons up to their permanent position at 75 degrees. GS monitored and controlled the lift using a computer controlled strand jack system supplied by Enerpac. The whole process was completed in 2 days.
Products: HSL8500 strand jacks 30kw hydraulic power units
The strand jack lifting technique originates from the concrete post tensioning principle. A strand jack can be considered a linear winch. In a strand jack, a bundle of steel cables or strands are guided through a hydraulic cylinder; above and below the cylinder are anchor systems with wedges that grip the strand bundle. By stroking the cylinder in and out while the grips are engaged in the anchors, a lifting or lowering movement is achieved.
The motion of the cylinders is driven by hydraulic power packs. They can be electric or diesel powered. Our sophisticated SCC software program synchronizes the motion of the strand jacks and adjusts the motion to the loads per lifting point.
Enerpac strand jacks are available with two types of strand: a standard strand of 0.62″ and compact strand of 0.71″. The 0.62″ strand can work with a dynamic load of 12 tons. The 0.71″ strand can work with a dynamic load of 17 tons. The number and type of strands used in a jack determine the safe working load of a jack. For lifting applications Enerpac strand jacks are calculated with a 2.5 safety factor against breaking load to working load.
Enerpac strand jack systems are available from 34 up to 1124 ton capacity. We also provide a full range of accessories like a strand guide, strand dispenser and recoiler. All systems are certified and tested under Lloyd’s witness. Each installation is delivered with an instruction and operation manual in English.
|Strand size||Model Number||Capacity|
*Lifting speed is based on strand jack capacity in combination with suggested power pack. When higher lifting speeds are required, we will supply bigger power packs
- Stroke 18.9″ (17.7″ effective)
- Electric motor 480 VAC 50/60Hz
- Tube bank: full nickel plated telescopic strand guiding
- Anchor block: high grade steel 42CrMo4
- Set of 4 Strandjacks
- 4 fixed anchors
- 1 SCC Control System
- 4 data cables 50 meters
- 4 Hose sets, standard length 5 meters each
- Strand dispenser
- Strand Dispenser
- Strand Guide
- Strand Recoiler
Enerpac is the recognized global leader in high pressure tools and equipment used in industrial markets. The history of Enerpac dates back to 1910, when our original company produced water pumps for the Ford’s legendary ‘Model T’ motor car. Enerpac’s reputation as a technology leader began in the 1920’s when the first hydraulic jacks were introduced. In the late 1950’s, an Industrial Products Division was formed and along with it, the brand name Enerpac. Today Enerpac operates from 28 facilities in 22 countries with over 1000 employees and manufactures thousands of products that it distributes globally through 1200 distributor partners with catalogs printed in 19 languages.
At Enerpac, our focus is to provide our customers with the most extensive line of products and accessories that maximize force – to increase productivity and make work safer and easier to perform.
Our comprehensive family of tools and equipment deliver reliable and dependable performance for virtually any industrial segment, from the smallest cylinder to computer-controlled systems for lifting huge structures.
Enerpac products are distributed worldwide, though all feature the convenience of local service and support. Our technical capabilities in support of integrated solutions projects such as lifting the Golden Gate Bridge in the USA, helping to launch the Millau Viaduct in France, and raising the roof for Beijing’s ‘Bird’s Nest’ stadium, make the safe and accurate movement of some of the largest structures on earth possible. Enerpac is a division of Actuant Corporation, a $1.6 billion diversified global manufacturing company, headquartered in Menomonee Falls, Wisconsin, USA.
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