Whether it's a new bypass to reduce traffic in residential areas, a building complex with space for individual living and working areas or an underground parking garage to compensate for limited parking availability on the ground level - construction is essential in many ways.
Owners want project sites to be completed as quickly and efficiently as possible. But residents and neighbors are not thrilled about the noise generated by construction work. And let's not forget: First and foremost, noise is an issue that affects the people who work with and around the equipment. Ultimately, the ear is our most sensitive sensory organ – noise control is therefore a matter of health protection and thus a key factor that Bauer Maschinen GmbH works hard to improve.
From drilling rigs to cutters, in recent years Bauer has set new standards when it comes to noise reduction at specialist foundation engineering sites. "Reducing noise is an extremely important topic in the new development and ongoing development of our equipment," says Christian Heinecker, Head of Business Unit Drilling Equipment at Bauer Maschinen GmbH. Construction work involves a variety of different noise sources, primarily from equipment, in particular the motor and various attachments. "Thanks to our Energy Efficiency Package, EEP for short, Bauer equipment is now significantly quieter than the predecessor models without EEP,” explains Christian Heinecker.
For example, Bauer's smart eco mode relies on dynamic regulation of the engine speed based on the respective action being carried out. This not only reduces cumulative noise emissions but also reduces diesel consumption. This is assisted by an automatic motor stop function that automatically switches off the equipment if it is not used for a certain period of time. Optional add-on modules, such as inflatable noise control cladding for the power head or the upper carriage, also have a positive effect and can even be retrofitted to existing equipment.
The silent mode is used for Bauer equipment featuring standard technology without EEP. "This operating mode makes the new BAUER BG 15 H and BG 20 some of the quietest drilling rigs available in their class," reports Christian Heinecker. The silent mode reduces the maximum engine speed and slows down the hydraulic consumers. The result: The equipment's noise level decreases by -2 dB(A). Compared with its predecessor model, the new BG 20 manages to reduce cumulative noise emissions by 9 dB(A). In some cases, individual measurements recorded values of just 100 dB(A). This is an extremely significant reduction in noise pollution, especially when we bear in mind that our perception of noise is not linear. A decrease of just 3 dB(A) means cutting the noise intensity in half, while a decrease of 6 dB(A) actually reduces the noise intensity by 75%!
Apart from the equipment, the drilling method also influences noise emissions. A differentiation is made between intermittent (e.g. Kelly drilling) and continuous methods (e.g. drilling with an auger using the displacement pile or double-head drilling method). The latter method combines pulling and concreting into a single process, and for this reason produces lower emissions during excavation than a method such as Kelly drilling.
However, this method is limited with respect to drilling depth and drilling diameter. For Kelly drilling, Bauer's adaptive Kelly retraction assistant reduces the speed during the retraction process at the joints of the Kelly bar, which has a positive effect on the noise level generated. Various assistants help during drilling and discharge, for example by preventing the drilling tool from overfilling (over-drilling) and thereby facilitating the subsequent discharge process. The optimal filling level of the drilling tool is displayed for the operator in the B-tronic. During discharge – an activity that used to be carried out manually – a one-directional or bi-directional spoil discharge assistant helps the operator.
In addition, a one-directional spoil discharge assistant can be used to optimize the intensity when shaking out the auger. "Whether EEP, silent mode or assistance systems, many individual components result in a noise-optimized package at the end,” summarizes Christian Heinecker. "We continually optimize our equipment and conduct our own foundation research as well as participating in publicly subsidized research projects."
Noise reduction is one of Bauer's top priorities, not just for drilling rigs but also for cutting technology. EEP technology is firmly established as the state of the art for Bauer's cuttercarrier equipment, the MC duty-cycle cranes. The cutter itself produces very low levels of noise and cutting is ultimately a low-vibration and thus low-noise method. The principal noise sources, apart from the motor of the support frame, are the cooler and the hydraulic system.
Particularly for projects in an urban environment, for instance subway construction, noise regulations can be very strict. "If the equipment needs to operate 24 hours a day in the city center, it needs to be appropriately quiet. The factors here are official requirements, health requirements and, last but not least, economic considerations," says Leonhard Weixler, Head of Business Unit Diaphragm Wall Technique at BAUER Maschinen GmbH. Bauer has developed a compact series of cutters with low noise emissions for such uses: the CBC Silent Cutter.
The Silent Cutter – available as CBC 30 for cutting depths of max. 80 m and as CBC 45 for cutting depths of up to 120 m – features an innovative concept: The hydraulic power pack, which ensures particularly silent operation, is not permanently attached to the rear of the support frame as is usual, but can be positioned on the side or even separately next to the support frame and connected via hydraulic lines. “This modular system, which is also available as a low headroom variant, offers maximum flexibility even in very tight spaces,” explains Leonhard Weixler.
The power pack is housed in a container with a length of 6 m, width of 2.5 m and height of 2.5 m. Compared with the standard MC duty-cycle crane from Bauer, the Silent Cutter produces noise emissions that are 3 dB(A) lower, which corresponds to approximately half of the perceived noise as described above. “That's a major step,” says Leonhard Weixler. This is possible because the separate power pack provides extra volume for noise insulation.
The Silent Cutters from Bauer are already well established in operation: For example, a CBC 45 was used in 2014 for foundation engineering work on subway shafts in the narrow urban canyons of Singapore. At the In-House Exhibition in 2017, Bauer presented a CBC 30 Compact Cutter with low headroom configuration featuring a height of just 6 m; additionally, a CBC 30 is currently in production for future use in the USA. In 2018, Bauer handed over a CBC 45 to a long-established customer from Japan. And as part of the large-scale infrastructure project “Grand Paris Express,” multiple compact CBC Silent Cutters have been used and continue to be used alongside numerous standard Bauer cutter systems consisting of a MC duty-cycle crane and BC cutter.