Kemroc KR 165 turns a WW II bunker into residential building

Specialist contractor Wilko Wagner GmbH has contributed to the reuse of historic buildings in Hamburg by executing an ambitious demolition project. In the upmarket district of Winterhude, an old World War II bunker was partially demolished, with the remaining structures being converted into a residential building. Hamburg has recently become a trendsetter in giving historical buildings a second life. There are still about 400 bunkers left in Hamburg, of which several dozen are high rise ones. For these buildings in particular, the preferred option is not to demolish them completely, but to dismantle sections with no value and to convert the rest into residential areas. One such bunker is located in the well-known district of Winterhude. The contract to demolish part of that bunker was awarded to Hamburg based Wilko Wagner GmbH.

In accordance with the regulations for the conversion of high rise bunkers, the street facade, the freestanding gable wall and the sidewalls directly facing neighbouring buildings must remain in place, whilst the back wall facing the courtyard was to be demolished. The inside of the bunker, originally consisting of six floors each with a ceiling height of some 2m, was to be completely dismantled from top to bottom. A shaft was first created by making a hole by hand through each of the 25cm thick floors and using a wire saw to cut an opening through a wall on the ground floor, through which around 7,000m³ of demolished concrete material could later be transported away by a compact loader. At a later stage, the interior of the building will be completely rebuilt. To create additional living space, the plan includes penthouse apartments to be built high up on the roof of the new residential building. In preparation for this, the existing reinforced concrete roof, around 220cm thick and weighing 400t, had to be removed.

In May 2022, preparation work started with the installation of noise protection panels and ceiling supports. Demolition began in July attracting extensive public and media attention when a 35t excavator was placed on the concrete roof. After removing the top bitumen layer, the excavator operator then cut a so-called foxhole through the concrete roof above the shaft using a Kemroc KR 165 drum cutter. Material created during subsequent demolition work was discharged through this hole. For residents and passers- by, a particularly spectacular part of demolition work was watching the window openings being cut through the 110cm thick, heavily reinforced facade walls of the bunker. Norbert Klatz, technical director for the Wilko Wagner Group, describes the three step process: “First, we marked out the area and drilled four holes in the bunker walls corresponding to the corners of the floor to ceiling window openings. Then, using our excavator and the Kemroc drum cutter, the bunker wall between these corners was ground down leaving a thin section of wall. The third step involved the removal of the remaining thin section of wall using an excavator with a shear.”

Wilko Wagner also used a water spray dust suppression system on the job site. According to Norbert Klatz, the system made it possible to keep dust levels within required limits. Even more important, however, was the fact that the vibration and noise levels were also within range during operation of the drum cutter. “Our demolition method worked very well technically,” he commented in mid-January, a few weeks before completion of the work. “There were only a few complaints from residents regarding the environmental impact of our demolition work. The monitoring report by the Environment and Occupational Safety Authority also gave us favourable results.”

www.kemroc.de

Epiroc VC 2000 does a fine job of removing rock in German mountains

A VC 2000 drum cutter from Epiroc was used for rock removal in a rainwater retention basin at the summit of the A45 motorway in the mountainous Siegen, Germany. The building authorities specified that the slope should be secured with a retaining wall. There was rock material on the surface that had to be removed with a high degree of precision to ensure that the wall, built from concrete piles, would not be damaged. The VC 2000 attachment that had been previously tried on various 20t-40t excavators passed the test with flying colours. It ensured that rock removal was quick and effortless and allowed construction work to be completed successfully within two weeks.

With its trademark V-shape, the VC 2000 has been designed to combine simplicity with high performance. Thanks to this innovative design, it creates flat surfaces without the material getting accumulated between the drums. The attachment can also be used underwater at a depth of up to 30m. In addition to its robust housing for increased operating time, it also has a durable drive shaft bearing with a maintenance free mechanical seal system, and also features an adaptable gear motor with high torque for greater productivity and longer motor service life.

www.epiroc.com

Simex TF 2100 drum cutter processes schist at a Ligurian landfill

Based in Vado Ligure, Italy, Ecosavona Srl. operates in the sectors of treatment of non-hazardous urban and industrial waste and energy recovery from renewable sources. The company has recently purchased a TF 2100 double drum cutter from Comai Spa, a Simex dealer headquartered in the town of Bra, Piedmont. An important player in the northwest Italy for the sale and rental of earthmoving and road building equipment, Comai also has a branch in Liguria. The drum cutter, mounted on a Hitachi ZX350LCN-6, was used at the Bossarino landfill, in the municipality of Vado Ligure, for wall profiling and earthworks. The plant is mainly intended for the disposal of non-hazardous waste, the recovery and recycling of various materials and the production of electricity from organic residues. The rock wall profiling was necessary for the subsequent installation of waterproof geomembranes, which are made of high density polyethylene panels with high resistance to mechanical stress. Among the most frequent uses of these panels is in ‘landfill capping’, providing permanent or temporary covers, which prevents the infiltration of rainwater into the ground and the stagnation of the leachate. For this reason, the Italian company needed a tool that would not only crush rocks, but would have high degree of precision to ensure correct installation of the geomembranes.

Simex’s ‘TF’ range has been developed to combine high hydraulic power with the selective breaking of the rock mass, ensuring the stability of the wall and producing material ready for immediate reuse. The frame’s special shape allows the reduction of the distance between the drums, increasing the total working area. In addition, the mechanical gaskets fitted on the drums enhance resistance to dust and other external agents. Weighing in at 2,380kg, the TF 2100 boasts a rated power of 120kW and a cutting force of to 71kN. Vado Ligure is a geologically complex area encompassing several lithology’s, including various types of schist. Specifically, the TF 2100 double drum cutter processed schist with reduced resistance to excavation due to high degree of fracturing. The drum cutter’s production rate varied between 25 m³/h and 30m³/h.

www.simex.it

Antraquip attachments help rehabilitate a lock in New York State

Antraquip, a US based manufacturer of mechanised rock and concrete cutting equipment, has recently supplied three AQ-5 drum cutters to one of its most longstanding customers in northern New York State.  Although this contractor has performed many demolition jobs using Antraquip cutters over the years, this project was a unique challenge. For the project, the contractor was on a particularly tight timeline to complete the controlled demolition of a wall within a lock which would need to reopen by spring to allow large ships to pass through the vital waterway to access the major cities in the Northeastern part of the US and Canada. The customer mounted the AQ-5s on Cat 349 excavators that were positioned on barges from where they would grind the concrete down to a depth of up to 1m.  This concrete was not your normal weathered concrete commonly seen on lock and dam rehab jobs, but instead had a hardness of 55MPa with steel support imbedded within the concrete.  As the machines worked their way down, the water level was dropped in order to access the deeper areas of the lock.  The project required operation of the three machines around the clock despite brutal weather conditions with temperatures dropping to as low as -34o.  Nevertheless, the entire project was completed well ahead of schedule in less than one month. The use of Antraquip drum cutters was the ideal option for a project like this as the AQ-5s provided the perfect combination of high productivity and precision while eliminating the possibility of over breaking or microfracturing that could damage the integrity of the lock walls.

www.antraquip.net

Two new models from Cat

New Cat RC20 and RC30 drum cutters are available with pin on, ‘S-type’, Cat pin grabber or ‘CW’ couplers. Rotary drum cutters are compatible with Cat hydro mechanical work tool brackets, which allow operators to move more smoothly from one task to the next. For space limited jobs, the drum cutter can be manually turned either 90o or 270o. Adding an optional hydraulic lines kit, the rotary cutter can be turned up to 180o for cleaning narrow trenches. Ideal for dredging applications, the rotary cutter can be submerged in water without any modifications to the tool. The direct drive motor offers high torque and production rates. With less space between the drums, the machine has been designed so that operators can build narrower trenches while also burning less fuel. Its picks are easily replaced with a simple tool. Mechanical seals help to lock in grease and keep dust out to operate longer between maintenance.

www.cat.com

Rock.Zone features ‘Rockwheels’

Rock.Zone GmbH, a Germany based trendsetter in excavator attachments, has an ample portfolio of drum cutters called Rockwheels to fit carriers ranging in operating weight from 0.7t to 125t. A special relief valve ensures motor protection: the drain oil goes directly to the return line, and if there is too much pressure in the drain oil section, the operator can see it on the valve. One of the drum cutters’ trademark features is a very small gap between the drums so a Rockwheel can be used for creating narrow trenches. For cutting extremely narrow trenches, Rock.Zone offers a specially developed Rockwheel trench cutter.

www.rock.zone