Integrated Hydraulics shapes World-Record Size Concrete Blocks

The Cartagena Port, in the province of Murcia in the South of Spain is expending its capacity and additional jetties are being built to further protect the harbor from the sea.

The construction process for the jetties is based on that of concrete blocks. Not the average size concrete block, but the largest blocks ever built worldwide, 70 x35 x 35 meters. NECSO, main contractor for this project, purpose built a large catamaran style concrete block builder for the project. The “KUGIRA” is capable of building a super-size block every 7 days. On one of the existing piers of the Cartagena port a sizable concrete factory serves the enormous catamaran in the harbor that carries the actual concrete block builder.

The “KUGIRA”, uses a sophisticated hydraulic integrated system to lift and lower the so-called construction – umbrella that holds the block construction formers. On both sides of the catamaran 15 sets of stage-lifting hydraulic units operated by 3 high-flow power sources and controlled by a synchronized PLC system operate the 35 meters wide and 70 meters long umbrella. The umbrella is shaped to form the blocks including the internal cells for stiffness and valves for the control during the sinking process.

Controlled Movement
Due to the size of the concrete block and thus the umbrella, the risk of twisting and therefore locking the umbrella between both catamaran walls is a serious thread to the process. For that reason a fully PLC controlled synchronized hydraulic system was designed by ENERPAC’s European Construction Center of Excellence. Technical director Jesus Gonzalez based the synchronized design upon a hydraulic climbing stage lifting technology.

Along both sides of the catamaran huge but lightweight constructions hold the climbing stage lifting steel notched plates, while the climbing stage lifting hydraulic units are fastened to the umbrella deck. As mentioned before, 15 units along each side of the umbrella deck. Each unit exists of an advanced ENERPAC hydraulic system including stroke– and and proximity–sensoring technology.

Climbing Units
All 30 climbing units comprise two long stroke hydraulic double acting cylinders of 70 tons capacity and two double acting hydraulic locking cylinders of 20 tons capacity. The long stroke cylinders, used for the actual lifting and lowering process, include a magnetic stroke sensoring system, which communicates the plunger’s position via a local manifold and valving unit to the central PLC-system. The locking cylinders also include stroke sensors that signal their position to the PLC-system where all data is processed and communicated back to the pumps and 2/2-way valves that control all cylinders (120 in total) in all 30 climbing units. The locking cylinders are used to fix the climbing units during the climbing process.

The main PLC-system is operated via a touch screen with a graphical user interface, continuously showing the actual stage of the process, including all parameters. Overall lifting and lowing accuracy of the entire system is 0,01 mm.

Flexible Design
The size of the port project and future upcoming projects of this type of port and jetty building was the main reason for NECSO to design the ship with maximum flexibility. Not only concrete blocks of 35 x 35 x 70 meters can be built, but also several other sizes. One option is to build 2 blocks simultaneously of 35 x 35 x 34 meter each, whilst another configuration allows the construction of one block of 35 x 35 x 34 and two blocks of 35 x 35 x 16 meter simultaneously. Consequently the ENERPAC hydraulic system is designed to deal with all these different configurations.

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