Handling hydropower9 December 2014
A wide range of equipment is used during the construction of hydropower and dam projects. IWP&DC takes a look at some recent product releases, and discovers how they have been used during project build
The Valais Alps is home to what will be one of the most powerful pumped storage power plants in Europe upon completion - the 900MW Nant de Drance scheme. The current underground facility uses the downward slope between the existing reservoirs of Vieux Emosson (2205m asl) and Emosson (1930m asl) to generate energy. One of the objectives of the project is to double the storage volume of the higher reservoir, Vieux Emosson, which means that the height of the dam has to be increased. The responsible contracting companies, Groupement Marti Implenia (GMI), commissioned Wolffkran with this job, following on from the company's involvement in the original dam wall construction in the 50s. The new challenges on the high alpine construction site are now being tackled by the luffing cranes Big WOLFF 1250 B and WOLFF 500 B.
Work had began in 2008 with the expansion of the access tunnels and development of the construction sites. The WOLFF 1250 B came into operation in the spring of 2012 for demolition work on the crest of the wall. The WOLFF 500 B was put to use last year with the start of the concreting work to extend the height of the wall. This year will see the wall increased by 21.5me to a final height of 65m, doubling storage at Vieux Emosson to 25Mm3.
According to Wolffkran, the contractor selected to work with WOLFF luffing cranes because of their high load capacities. The 1250B, one of the strongest tower cranes in the world, is in operation with an 80m jib and a maximum load capacity of 40 tons at the Vieux Emosson reservoir. The high load capacity was required to lift the heavy eroding machines and excavators onto the wall. The excavated material could also be lifted from the wall in 40-ton skips, saving a lot of time and money. The WOLFF 500 B, with a 60m jib and a maximum load capacity of 30 tons, supported the Big WOLFF in the concreting work to raise the height of the wall. In total, the red giants broke down 25,000m3 and will move 70,000m3 of concrete to extend the height of the wall.
The two WOLFFs were suited to the job due to their assembly concept, says Christian Maillet, site manager at GMI. "Due to their long jibs, the tower heights of the luffing cranes, at 30 and 45 meters, could be selected significantly lower than would have been possible with a saddle jib crane, he explains. "This meant that both WOLFFs could be erected to end height with a mobile crane and did not have to be climbed afterwards."
"Assembling tower cranes at this level represents a major challenge," adds Philippe Gremaud, area manager at Wolffkran. "Heavy snowfall and severe cold weather added further complications to the assembly. But we were able to draw on our experience with such complex assembly conditions, and managed to erect the 1250 B in seven days and the 500 B in just three."
The luffing cranes are also suitable for the cramped conditions at the site, because they are designed to work as space-efficiently as possible. The dam is flanked at both ends by high rock faces. Using the WOLFF luffing cranes, it is not necessary to slew over the high rock faces since they can slew past them very closely. Furthermore, they can rotate freely at any time on the narrow mountain construction site with their jibs in a steep position.
The WOLFFs went into hibernation, so to speak, in November 2013, because work cannot proceed at these altitudes due to the large amount of snow and high wind speeds. To avoid any danger, the jibs of the two cranes were dismantled and stored safely. The red giants began to resume their work in the spring, on higher towers of 50 and 60 meters respectively.
Staying in the world of cranes, Liebherr recently announced it has updated its successful 160 EC-B Flat-Top crane and has now unveiled its successor, the 172 EC-B 8 Litronic. The crane's lifting capacity has been increased to provide users with increased performance, with its erection process been simplified even further.
The redesign of the new 172 EC-B 8 Litronic Flat-Top crane has resulted in a major increase in performance in terms of its lifting capacity - increasing it by 15% over the full length of the jib. The new Flat-Top crane will now hoist 2100kg at the jib head with a radius of 60.0m and offers a maximum capacity of eight tonnes. This represents an increase of 250kg at the jib head over its predecessor. The modular concept and the compatibility of the tower systems among each other ensure that the crane is suitable for a wide range of uses, says the company. With the Liebherr 120 HC, 170 HC or 256 HC tower systems, free-standing hook heights of up to 71.4m can be achieved.
Another new feature of the 172 EC-B is the new erection concept for the jib. The load hook and trolley remain on the jib pivot section during transport. That completely eliminates the erection work for the trolley. The hoist and trolley travelling ropes can also be reeved easily with little effort providing massive benefits particularly for jib erection in the air. Improved quick-release fastenings on the cab and switchboard platform allow the compact head to be split quickly to reduce the erection weights. And the quick-release electrical connections ensure that the switchboard and cab can be connected quickly without any errors.
The Liebherr 37kW frequency converter hoist gear is included in the basic version and allows empty hook speeds of 135m/min. A 45kW frequency converter hoist gear is also available as an option. The frequency converter hoist gear is only used in 2-line mode. Hook heights of up to 328m and empty hook speeds of up to a maximum of 177m/min ensure that the crane is economical to use.
The new 172 EC-B 8 Litronic is supplied with an advanced Litronic crane controller. Functions such as redundant load moment measurement, manipulation-proof commissioning and the monitoring of hoist gear brake with managed lowering in emergency mode provide a very high level of safety. Settings such as slewing gear modes and the trolley speed can be adjusted quickly and easily using the electronic monitor system (EMS). In crane mode, the increased sensor resolution of the new Litronic crane controller system also provides improved operating properties. The increased sensor resolution provides the basis for sensitive and precision operations even at high speeds. This results in enhanced crane operation comfort and much greater safety on site.
Bobcat has launched new advanced versions of the company's two largest rigid frame telescopic handlers. The new T40140 14 m and T40180 18 m models both have increased maximum lifting heights and are based on an easy-to-use design that provides class-leading efficiency and productivity backed by state-of-the-art safety systems.
The much enhanced T40140 and T40180 telehandlers include many new features and are available in both Stage IIIB and Stage IIIA compatible versions. The Stage IIIB versions are powered by the 75 kW (100 HP) Deutz TCD 3.6 L4 diesel engine which utilises EGR (Exhaust Gas Recirculation) and a DOC-only solution to meet the new emission standards. The new Stage IIIA models are powered by the Perkins 1104D-44TA 75 kW (100 HP) diesel engine.
For the T40140 telehandler, the maximum lift capacity is 4.1 tonne and the maximum lift height is 13.71 m. The capacity at maximum lift height is 4 tonne, while at maximum reach (10.43 m), the capacity is 1.3 tonne. Unloaded, the T40140 weighs 10.29 tonne and provides a tilt crowding force of 12300 daN.
The T40180 telehandler has a maximum lift capacity of 4 tonne and a maximum lift height of 17.52 m. The lift capacity at maximum lift height is 2.5 tonne, while at maximum reach (13.7 m), the lift capacity is 560 kg. Unloaded, the T40180 weighs 10.79 tonne and provides a crowding force of 12300 daN.
The new T40140 and T40180 models deliver market leading load chart performance in their classes, when operating on tyres alone, where the high stability of the telehandlers ensures minimal loss of lift height and capacity. As a result, the new T40140 model offers the highest lift capacity of 4.1 tonne, whilst the T40180 telehandler has an unmatched maximum lifting height of 16.2 m when operated on tyres.
The hydrostatic transmission in the T40140 and T40180 telehandlers provides a 95% performance efficiency, providing high power coupled with low fuel consumption. The hydrostatic transmission makes it possible to place a load to the exact mm. In addition to precision, this is an important factor contributing to safety, particularly when loads have to be positioned at significant heights or distances from the machine.
The patented Bobcat side shift system is a standard feature on the T40140 and T40180 models, ensuring there is no need to reposition the machine if it is not aligned with an opening, providing maximum flexibility with a +/- 700 mm side shift. This is combined with the unique integrated frame levelling system which works independently of the main frame to provide a tilt correction on inclined surfaces of +/- 4o on tyres and up to +/- 12o on stabilisers for safe, optimum positioning of loads.
Featuring optimised ROPS/FOPS protection, the new cab on the T40140 and T40180 telehandlers offers increased safety and visibility through a curved front window providing a better view of loads and attachments at height; a larger back window increasing sight to the rear and a cab door with windows above and below the handlebar for optimum visibility when manoeuvring close to walls or other obstacles. Overall the new cab is designed to provide an exceptional work environment and a new higher level of comfort for the operator, reducing fatigue and improving safety and performance on site.
From their comfortable mechanical or air suspension seat, the operator is provided with an ergonomic array of machine controls all within easy reach and including a new forward/reverse (FNR) control button on the joystick; a new digital display; an adjustable steering wheel and an integrated airflow solution.
It's not just during the construction of new and refurbishment projects where materials handling equipment can prove its worth - they're also needed when it comes to the removal of projects.
The final stages of returning the once-polluted Cuyahoga River in Ohio to its pre-industrial splendor included the removal of the Sheraton Mill Dam and the LeFever Dam that once provided hydroelectric power for thriving local industries.
RiverReach Construction, specialists in environmental stream and wetland restoration projects, peformed the demolition task quickly and efficiently using Atlas Copco hydraulic breakers equipped with underwater kits.
The first was the 12m long, 3m high Sheraton Mill dam. It had to be approached from upstream and RiverReach's solution was to set a mini-excavator, with the SB 552 breaker attached, on a modular barge and float it into place just behind the dam.
Operator Shannon Swaino began by using the SB 552 to open up "windows" and let the water flow downstream. The water level behind the dam then gradually sank. Next, Swaino entered the river with a 36-ton excavator and the powerful HB 3100. The dam came down in a day. "It was almost too easy with that big breaker," said Swaino.
Next to be tackled was LeFever Dam - 27.4m across and nearly 4m high, with a significantly larger volume of water behind it. RiverReach was able to construct an access to the river at the start and Swaino could approach it from the downstream side, so no barge was needed and the job was completed quickly.
The removal of the dams exposed the Cuyahoga River's white-water rapids and waterfalls, which have been hidden from the local residents for a hundred years.