Efficient and secure loading of precast concrete components presents many precasters with a challenge, especially in facilities where double and solid walls are manufactured in addition to the floor plates for floor systems. While the loading situation for floor plates is still relatively simple – taking place mostly by crane or forklift that pick up the horizontally stacked wall elements – the situation for double and solid walls is far more difficult. The main reason for this is that the elements are deposited on a rack in a vertical position. This frequently leads to an unequal load distribution, which makes it impossible for the crane to securely pick up the units. Another point is that many precasters nowadays transport their products to the construction site on inloader trucks. The inloader racks, on which the precast parts are prepicked, must be positioned on floor level for loading into the truck.
Double wall inloader racks efficiently loaded
The French precaster SPL searched for an economical solution for loading the double walls in a new production facility located in Landaul in Brittany. “In the outside storage area, the floors, double and solid walls are transported to several parallel pick-up stations. This initial situation has to be considered already in the planning stage,” explains Stéphane Renaudin, the plant manager at SPL.
In the picking area, a hall crane first stacks the double walls onto an inloader rack. Next, a lifting transporter moves the loaded rack outside onto a 3-rail platform car that travels in longitudinal direction to the final loading position, where the double walls are deposited on A-frames. At this point, a conventional solution would have required a considerable investment for the lifting operation required for placing the double walls on floor level. “We would have needed to move around 100 m3 of rocky ground to ensure a smooth loading process. This would have required a great deal of time and would also have been uneconomical,” says Philippe Marrié, project manager sales at Vollert Anlagenbau.
Bearing capacity up to 25 tons
For secure and efficient loading of the inloader racks, Vollert developed a special loading beam. At a bearing capacity of up to 25 tons and suitable for handling precast components with maximum heights of 3.80 m, the load beam is fitted with electrically powered arms that can be extended and grab the inloader rack on the long sides. If the rack is fixed in the load beam, the two-girder bridge crane raises the rack with two synchronously switched lifting units and moves it to its final pick-up station. The load beam is so secured that it is impossible to open it in raised condition. Once the inloader rack has been deposited on ground level, it can be directly picked up by the truck.
If required motor-powered
The load beam, at a dead weight of nearly 2 tons, measuring 6 x 2 m and with a height of 4.8 m, is extremely compact, although it can be technically widened to 3 m. If required, the beam can also be fitted with a motor-driven width adjustment so that different concrete parts can also be loaded. When not in use, the beam can be separated from the crane so that the crane can be used for other purposes.
With the new loading technique, the processes at SPL could be greatly optimized. More outstorage and loading operations can now be carried out, leading to an increase in overall productivity. “In Vollert Anlagenbau, which also planned the plant at this location in Landaul and put it into operation at the beginning of 2011, we have an innovative partner that presented an economically thought-through solution,” summarizes Stéphane Renaudin.
Vollert Anlagenbau GmbH
+49 7134 52 230