Up we go27 July 2021
Sotiris Kanaris talks to jack-up systems suppliers about their product portfolio and the advantages that this technology offers.
Jack-up systems are chosen for a wide range of applications, from installing small industrial machinery to lifting huge topsides. Certain characteristics of these systems make them safer and more cost-effective than other lifting equipment. In some occasions they are the only solution for the job to be executed.
Sarens designed its first jack-up system in the late Nineties. “Although the pack-and-jack principle was already used long before that, using simple jacks and hardwood blocks for instance,” says Peter Huygebaert, head of engineering department at Sarens. The company initially launched the CS600, a 600t capacity jacking tower, and the 100t PJ100. After these two, Sarens developed five more systems, in the following order: the CS250, PJ 250, CS5000, CS1000 and the CS350.
“Our biggest jacking system, the CS5000, with 5000t capacity per tower is already ten years old and it still serves the market well, given the huge capacity we gave it back then. After the CS5000, we focused our development efforts on smaller systems which serve various markets such as prejacking of bridges before installation, jacking offshore wind turbine jackets onto grillages and supports, exchanging overhead gantry cranes and others,” Huygebaert explains.
“Where the earlier types relied on a single jack per tower and feeding at the top, the more recent designs have four jacks—and therefore a more sophisticated control system—and use a bottom feeding principle, which limits working at height and meets highest safety/industry standards.”
The smaller systems in Sarens’s portfolio have jacking elements that can be handled manually. “The larger ones obviously not, but those systems have easy feeding systems to handle the elements. For ease of transport, even the largest system (CS5000) does not exceed standard trucking dimensions and weights,” Huygebaert adds.
Mammoet developed its first jack up system in 2011, the Mega Jack 5200. With a capacity of 5,200t per tower, it remains the highest capacity system in its portfolio.
“We started with the development of the Mega Jack 5200, which was required for the top end of the market to jack up large topsides. It was developed to jack-up the 42,780 Exxon Mobile Arkutun Dagi topside for DSME; a world record lift,” says Ronald Hoefmans, head of R&D and Fabrication at Mammoet.
Richard Verhoeff, sales director at Mammoet, added: “Capacitywise, it could lift more than double the load of systems in the market serving the same purpose. Technology-wise, it has been a big step up in lifting accuracy, stability and safety – with jacking cartridges inserted at ground level, reducing working at height. All of this added up to offer big possibilities for the shipyards building these giant topsides.”
Apart from lifting topsides, Mammoet has also used its Mega Jack 5200 for bridge installations of bridges like the Hong Kong Sky Bridge and Wellsburg Bridge in the USA. Currently the system is being deployed at the biggest LNG construction shipyard in the world.
The next jack up system Mammoet developed was the Mega Jack 800, which has a capacity of 800t per tower.
“We needed a smaller jacking system for the work we perform in the civil market, ports, power generation and to handle smaller loads in the oil and gas market,” says Hoefmans. “This system is extremely stable and was designed to operate on barges for the installation of bridges. The cassettes in a tower of this system are bolted together. The tower itself is bolted to the jacking base and the base can be clamped to the barge. In this way the system can have a huge amount of horizontal load. This is needed when transferring loads from the jacking system sitting on a floating barge onto fixed bridge foundations.”
The Mega Jack 800 has proven very popular and, earlier this year, Mammoet announced the addition of ten more units to its fleet.
“The reason for expanding our fleet of Mega Jack 800 systems lies in the number of projects globally that give an increased demand for this capacity of system,” says Verhoeff.
The latest Mammoet jack-up systems are the Mega Jack 500 and the Mega Jack 300. Talking about the Mega Jack 300, Verhoeff comments: “We have developed a cradle system that can ‘hang’ the MJS300 towers in-between SPMTs, making it possible to pick up the loads at lowest possible height and drive the object in at height.”
In its fleet, Mammoet currently has 20 towers of Mega Jack 300, 12 Mega Jack 500 towers, 22 Mega Jack 800 and 16 towers of Mega Jack 5200.
“Fagioli is able to provide a jack-up system with a total capacity of 2,000t, extendable to 4,000t,” says Rudy Corbetta, publicity officer, marketing and communication at Fagioli.
He says the technology and lifting capacity evolved dramatically due to the requests for more demanding and challenging operations to be executed. “Moreover, the handling operations of this system have been getting easier in terms of moving the single sections of this device around.”
Corbetta says the system has self-contained hydraulics in each jack-up unit. He highlights the safety of the system, as it is operated and controlled remotely by a computer. In terms of the transportation, the whole sections of Fagioli’s jack-up system can be easily containerised and shipped. Enerpac launched its first jack-up system over a decade ago, and now its portfolio comprises two product series, the JS Systems and SCJ.
The JS Systems series, consists of four models (JS125, JS250, JS500, JS750), offering capacities per leg of 125t to 750t. All four models were launched in 2017. As to how the systems have evolved over time, Pete Crisci, product line director at Enerpac Heavy Lifting Technology, answers: “We have standardised and improved our control systems over time, providing finer control over the lift and enhancing safe operation.”
In 2019, Enerpac launched the SCJ-Series Self-Locking Cube Jack series, which now comprises the SCJ-50 and SCJ-100.
Crisci explains the difference between the two lines: “JS Systems are self-contained units— pumps, lifting cylinders and controls all in the leg. Cube Jack is a standalone lifting device that requires connection to an external hydraulic power source and controls. “JS system is best suited for heavier loads (125 to 750t per leg) with higher lifting capacity (6-30m) requirements, and critical unique lifting projects. Cube Jacks are best suited for lighter loads (50-100t each leg) and lower heights (2-3m), and best for wider variety of general lifting jobs.”
In terms of applications, Crisci says Cube Jacks can be used for lifting structures for expansion, lifting machinery on and off of transport vehicles, and performing maintenance in factories.
JS Systems are best suited for handling port cranes, bridge construction as well as maintenance of large machinery used in construction and mining.
“What is great about the JS system is that you can run more than the typical four lifting legs on a system. It’s expandable as needed based on the application. So additional capacity is gained by adding additional legs,” says Crisci.
With systems in the market offering 5000t capacity per leg, the lifting power of jack-up systems definitely gives them a comparative advantage over other lifting equipment. What are other comparative advantages and disadvantages?
Crisci says the main advantage of their JS Systems over traditional methods is the incremental mechanical locking.
“Normally in incremental lifting, the operator must periodically place themselves or part of themselves under the load while it is supported by hydraulics. This is a risk that every lift planner tries to avoid. So because the JS system mechanically supports the load prior to the operator needing to physically interact with the load, it is a much safer method.”
“We also offer accessories for the JS systems and Cube Jacks including transport trolleys that allow the load to be shifted horizontally once it is lifted. This makes the JS system just as versatile as a hydraulic gantry system in some extreme applications, with even higher capacity per leg and greater lifting height.”
Mammoet’s Hoefmans also highlights the enhanced safety offered by mechanical locking: “The advantage of jacking systems is that between every jacking stroke the system is mechanically locked. It is basically a steel support structure and safe for people to work underneath. It’s not a suspended load, like a load hanging from a crane.
“On the other hand, a jacking system is a completely different machine and cranes have the advantage that they can lift up a load and can rotate it in the hook. A crane can also lower a load onto the ground or on supports. A jacking system normally sits underneath a load and has a certain starting height. However, our large jacking systems can be used in tandem with skidding systems to achieve some truly incredible things, for example during the Malikai project in Malaysia, where we jacked up an almost 14,000t topside to 40m, then skidded it 90m horizontally at height.”
Sarens's Huygebaert says the biggest advantage of jack up systems is that they self-erect while jacking, limiting the work at height and preparation time. He added that climbing systems have a small footprint and don’t not require much space around the lifted items.
“Comparing for instance to (strand jack) gantries which require structures to be built around and over the item to be lifted, preparation time is therefore very short. However, the jacking itself may take a bit longer than with a lifting gantry, which doesn’t require elements to be fed into the towers.
"Climbing systems are therefore mostly, but definitely not exclusively, used for the jacking of a single item, rather than for lifting multiple loads consecutively.”
LIFTING ON BARGES
The jack up systems are often placed on barges to perform bridge installations. A recent example is the use by Sarens of its CS 1000 system on twin barges, and four 650t strand jacks, for the installation of the 120m long middle section of the new Schierstein Bridge. The bridge spans the river Rhine to connect Mainz and Wiesbaden.
These jobs require extensive planning and preparation. Sarens’s Huygebaert says: “Climbing systems, especially the larger types, have a considerably high local load on their footprint. Where on soil, this load is typically distributed by means of load spreading mats, the use on barges often requires the load to be transferred to the barge’s strong points (webs, bulkheads, etc) by means of grillage beams. As climbing systems only move the centre of gravity up, the barge should be ballasted first to take out any trim and heel angle before the jacking operations start.”
Talking about the challenges of such jobs, Mammoet’s Verhoeff says: “The main challenges when utilising jacking systems on barges is spreading the load evenly among the strong-points of the barge(s) and keeping a stable operation. Especially if we need to jack-up to large height; you can imagine the center of gravity raising to a level where stability is lower than it would be if performing the load-out closer to the surface of the water.
“To increase stability, we can insert bracings between the towers. On one of our recent projects in the Netherlands, we performed a carousel action using the controlled jacking systems on top of SPMTs where the SPMTs rotated the barges underneath the bridge 90° to make it ready for installation.”
He adds that the successful completion of many projects relies on months, or even years, of extensive planning and it is not just a matter of having the right equipment.