May 5, 2020
Wherever know-how, experience and state-of-the-art machinery and equipment are required, you will find the Oettinger Group's demolition specialists from Malsch near Karlsruhe. With a team of over 130 experts, the Oettinger Group undertakes challenging construction projects and implements individual customer wishes without complications.
A particularly powerful attachment was required for the partial demolition of a former public administration building with integrated air-raid shelter in Karlsruhe, Germany. The buildings comprised 18,000 m³ of enclosed space and 4,000 tons of reinforced concrete material.
First of all, gutting and remediation work was carried out with the aid of a MG 5000 Multi Grapple. This was followed by the demolition of a connecting bridge and the public building, including the heavily reinforced air-raid shelter.
The well-proven CC 5000 demolition cutters were used for the above-ground demolition. It has a weight of about 5.5 t and a jaw width of 1,600 mm. Strong walls and substantial foundations were waiting in the basement. The walls which had been pre-slit with the HB 4700 hydraulic hammer were finally cut out with the new CB 5500 concrete buster and prepared for pulverization.
The experienced machine operator Marius Mayer values the power and precision of the new development: “The CB 5500 is designed for heavy duty assignments and is ideally suited to breaking the structures of thick reinforced concrete walls, trusses, beams and foundations. The tip penetrates the concrete vigorously and "bursts" it from inside. Areas of application include industrial demolition or inner-city demolition where vibration is to be avoided. The benefits are particularly evident in the demolition of foundations.”
Managing Director Robert Oettinger explains that it is becoming increasingly important to dismantle foundations without major vibrations. Mayer adds: "Because of its construction and its huge jaw width, the CB 5500 enables me to crack even foundations made of the hardest concrete. The work cycles are fast and the capacity of the shears is outstanding."
The product range has recently been extended to include the CB 5500 and CB 7500 and now includes six models with operating weights from 320 to 7400 kg for excavator classes from 2 to 85t. The CBs have been specially developed for heavy foundation work and are particularly suitable for demolition with long-front excavators and in areas where the hydraulic hammer cannot be used.
The CB 5500 was designed as a two-cylinder system, as is usual with Epiroc cutters. This brings more force to the tip and prevents reaction forces. This ensures outstanding performance while protecting the carrier equipment. According to Jens Westermann, Sales Manager at Epiroc Deutschland GmbH, the 360-degree rotation with pressure relief valve should be highlighted: "When the cutter grip the material at an oblique angle, the built-in pressure relief valve enables an automatically triggered movement that moves the cutter into the correct position. This valve provides good protection for both the cutter and the carrier from harmful reaction forces".
The combination of 2 movable cutter arms and 2 hydraulic cylinders provides a further benefit: an almost constant crushing force, even with almost closed arms. While conventional models with only one cylinder or only one movable arm usually achieve a maximum of 70 to 80% closing force at the tip of the cutters, the CB 5500 and the CB 7500 can maintain up to 90% in an (almost) closed condition. The independently movable cutter arms also prevent displacement forces on the cutter and the excavator. "This makes a precise and smooth operation possible, even at great heights and in difficult to reach places," explains Jens Westermann.
The CB 5500 is designed for the 50-65 t carrier class and is operated with an working pressure of 350 bar. The jaw width of the CB 5500 is 1,600 mm and the jaw depth is 1,060 mm. The jaws are made of Hardox 650 and additionally reinforced in the areas most exposed to stress. The tips can be welded on. The lubrication points are also optimally accessible and yet protected against possible damage.
It features impressive opening and closing times of 4.1 and 3.5 seconds respectively, as well as a cutting force of 150 t at the jaw tip. The short working cycles are made possible by the built-in rapid motion valve. These performance parameters and the associated increased efficiency were also decisive for the Oettinger order in Karlsruhe.
The concrete demolition cutter was particularly impressive in test operation and therefore immediately adopted by the Oettinger Group. Managing Director Robert Oettinger summarises: "With the CB 5500 we have added a very good machine to our fleet, a machine that is outstanding for its size".