During Bauma 2019, in Munich, Germany, specialist foundation equipment manufacturer Bauer Maschinen GmbH unveiled the latest machine in its BG product line - the new BG 33 V.

The BG 33 joined the range to replace the former BG 30 BS95 and BG 28 BS80. The BG 28 and BG 30 platforms have been globally popular rigs for many years, the BG 28 being Bauer's all-time best seller. When production of the last BG 30 was completed in 2017, Bauer Maschinen's in-house design team had already begun the process of developing its successor.

With urban job site environments being one of the main topics of focus for Bauer's design teams, the BG 33 has been designed and developed with these locations in mind. The rig is based on the Bauer-built BT 85 base carrier, which features a shorter swing radius than its predecessors and equally a reduced working width due to the patented integrated service platforms. The ballast weights are stackable which means that even at maximum working capacity, the swing radius of the rig will never increase. With a reduction in radius of over 600mm in comparison to the previous BG 30, the BG 33 is an ideally sized rig for urban job sites in the mid-class ~100t range.

Of equal focus when developing the BG 33 was the latest version of Bauer's B-Tronic on-board computer software. Released along with the BG 33 at Bauma, B-Tronic 4.3 offers more operator assistants than ever before.

B-Tronic assistants

In addition to the already well-established assistants in B-Tronic such as Kelly visualisation (which has had a major upgrade in the Kelly locking position feature), crowd assistant and the rock drilling assistant in Kelly mode, plus the standard drilling and concreting assistants in single pass modes, Bauer has included a whole host of new, hands-free controls to ensure smooth operation and reduced stress for the rig operator.

Taking the view that during a 10-hour plus shift, even the best operator will become fatigued and has the potential to make mistakes, Bauer operator assistants aim to take the stress away from the operator and keep the rig performing at peak efficiency for the whole working day.

One particular assistant system for Kelly drilling, which saw a major push forward during 2019, is the Kelly speed assistant. This system is designed to automatically lower and retract the bar for the operator with total hands-free control. In conjunction with information from the Kelly visualisation programme, the computer is able to lower/retract the bar at the most efficient speed possible without ‘banging' the elements together during the transition phase. The programme will automatically slow down the winch during transition and speed up again once the element has made contact.

The system also automatically detects if a Kelly section has not been unlocked correctly after the dig is complete. If the system sees that two elements are being lifted simultaneously, retraction of the bar is immediately stopped. Using the Kelly speed assistant not only increases the speed of pile production, but it will also potentially reduce process noise and downtime/repairs to the Kelly bar.

Other new assistants have also been developed to improve the performance of the equipment and the accuracy of pile reporting. Crowd Plus is the stand-out addition, while the absolute depth feature allows the operator, and subsequently the project engineer, to track the pile depth from ground level at all times and not from the top of casing as is normal. Absolute depth takes into account the tool being used including its nominal length and adjusts the recorded depth accordingly.

Besides being supplied with the quietest ever engine package on a model in this class, the BG 33 is also equipped with Bauer's Energy Efficient Power (EEP) package. EEP is standard across the BG range and has been proven to offer genuine, tangible savings on both diesel consumption and CO₂ emissions.

From a re-engineered main winch drive system, which actually recovers energy spent while lowering the Kelly bar down the borehole, to Smart-Eco mode control, which allows the engine to dynamically adapt to the current power requirement with a view of keeping the engine speed (and noise emission) as low as possible, along with several other re-engineered systems in between, the savings all equate to much-improved fuel economy and lower pollution.

At the time of writing, Bauer Maschinen GmbH had delivered six BG 33 rigs with half of those being sold into the UK market. Doncaster-based specialist deep foundation contractor, Cementation Skanska purchased and took delivery of its first BG 33 in November 2019. The rig was assembled, and the final commissioning carried out by Bauer Equipment UK at Cementation Skanska's specialist plant facility, Bentley Works. Upon completion, the rig was mobilised immediately to its first job site.

Testo's upgrade

The BG 33 was deployed by Cementation Skanska to the A19 Testo's roundabout project near Newcastle Upon Tyne. In doing so, the rig became not only the first BG 33 to start work in the UK but also the whole of Europe. It was also the first Bauer machine equipped with a Stage-V engine to commence work in the UK.

The A19 Testo's upgrade project, with a total value in excess of £125 million (US$164 million), is an upgrade of the existing roundabout into a new north-south flyover. The roundabout, a major junction linking the north-south A19 corridor with the strategic eastern route around the busy Tyneside suburbs is a known traffic blackspot in North East England.

Construction commenced following development consent for the project, having been granted by the secretary of state for transport in September 2018 with a view to improving economic growth in the area, while providing a safe, reliable, serviceable and integrated public road network. Cementation Skanska, working for Costain on behalf of Highways England, was awarded the contract to install the rotary bored piles to facilitate construction of the flyover. The new interchange is expected to be fully open by the summer of 2021 with Cementation Skanska's role in the project being completed by Q2 2020.

Cementation Skanska first mobilised to site during Q3 2019 to install 1,050mm and 1,200mm bored preliminary test piles. The BG 33 was mobilised for phase 2 at the end of November 2019, which was scheduled for a four-week period with the BG 33 being used to install the south pier piles for the new flyover.

The structure required 20Nr 1,050mm diameter rotary bored piles drilled to a nominal depth of 30m, along with 4Nr 1,050mm rotary bored anchor piles drilled to 24.5m to facilitate the load test. All the piles had full-length cages installed to just below platform level.

The site itself, located in the centre of the existing roundabout, presented a challenging working environment for Cementation Skanska, simply taking delivery of concrete had to be managed extremely carefully as the access and egress was directly into live traffic on the busy interchange.

In those challenging ground conditions, the BG 33 was tasked with the installation of 25m plus of 1,180mm casing which was toed 1m into the Pennine coal measures. The pile was then drilled to a final depth of ~30m into the prevailing mudstone with a minimum 4.5m socket installed. Groundwater was present from 10m below platform level, therefore the majority of the pile had to be excavated using a specialist digging bucket supplied by Cementation Skanska.

Cementation Skanska project engineer, Cassie Fysh says: "We achieved our anticipated production rates using the BG 33. The machine handled the range of ground conditions well, including drilling through some large granite boulder obstructions. The rig was capable of installing and removing up to 25m of segmental casing without struggling."

The tender output was achieved by the very experienced site team working to ensure phase 2 could be completed on schedule and to budget. The challenging ground conditions made installation of the casing difficult, approximately 25m of stiff clay and glacial till forced full use of the 340kNm available torque from the rotary drive unit. The machine operator was able to utilise the Bauer rock drilling assistant to help with the laborious task of casing installation through the cohesive material.

Cementation Skanska also utilised its automatic casing drive adaptor on the project to reduce the likelihood of slips, trips and sprains while installing and, equally, removing the casing, allowing for a safer and more efficient sequence.

Mitchell Newington-Evans, Cementation Skanska's operator, says of using the rig: "The BG 33 is unbelievably quiet, to the point where we have to check the engine is actually running! The fuel efficiency is also excellent in comparison to some older rigs I've operated. The performance of the rig on its first job has been exceptional, we experienced no issues during the project and even though the machine was working extremely hard it didn't let us down. I have been very impressed with the integrated service platforms, being able to safely stow away the walkways is a huge advantage on a congested job site."

High extraction forces

Handling this large amount of particularly heavy casing (809kg/m), along with the high shaft adhesion factor created by the underlying clay and glacial till, could have potentially caused issues when trying to extract the casing tube. Cementation Skanska was able to take full advantage of the latest Bauer operator assistant system specified and delivered with the BG 33, Crowd Plus. The Crowd Plus system allows the rig's operator to safely mobilise the maximum combined extraction force of both the crowd and main winches simultaneously. By using the specially designed Crowd Plus pulling adaptor on the Kelly bar, the BG 33 can mobilise an extraction force of 595kN (330kN crowd force and 265kN main winch) onto the casing. Due to the high extraction forces of the BG 33, the site team were able to extract the casing without the need to rotate, thus guaranteeing no movement of the reinforcing cage.

Cementation Skanska mobilised back to the A19 during Q1 2020 to complete phase 3 of the works. This 10-week programme involves the installation of larger diameter piles for the north pier and north and south abutments. The actual diameters are 1,300mm casing and 1,180m tools. The piles are again due to be drilled to a nominal length of 30m with casing installed into the mudstone at ~25m.

When asked about the investment into the acquisition of two new BG 33's, Cementation Skanska's director of plant and Bentley Works, Steve Joynson says: "Following lengthy research into what was available on the market, we decided to go with the Bauer BG 33 machines because of the overall capability and potential performance of the rig.

"Having operated Bauer rigs for almost two decades, we were well placed to understand the quality that Bauer provides in terms of the machinery itself, the build quality and the aftersales support. The BG 33 offered Cementation Skanska a perfect option to replace our existing BG 28s, which have served the company well for many years.

"Having the first Stage-V BG 33 at work in the UK and indeed Europe was just another first for Cementation Skanska. We are proud that we can offer our clients the most current technology and the latest equipment.

"Our second BG 33 has since been delivered and is working on its first project. Another benefit was the commissioning time; both rigs went to their first job site within a week of delivery. Much of the hard work, including making specific end-user requirements, filling with biodegradable hydraulic oil, corporate branding and the like were carried out at the Bauer plant in Schrobenhausen, Germany before the rigs left for the UK.

"Cementation Skanska-owned drilling rigs of this type are expected to achieve a minimum of 65 per cent utilisation across all disciplines - the conversion and rigging time is good and it has been great to have already carried out continuous flight auger (CFA), full displacement piling and Kelly work with our newer BGs. Production levels have been as expected; the first project required the installation of 25m plus of 1,180mm segmental casing - just what you need on the first job if you want to prove capability.

"In terms of efficiency and the whole environmental impact, Cementation Skanska is absolutely committed to ensuring our machinery is the greenest it can be. We are fully monitoring the carbon footprint of the machines, not only on the job site but prior to delivery so we can understand the whole story and life cycle of our equipment."

"Cementation Skanska has committed to becoming fully carbon neutral by 2045," explains Joynson. "The investment in these BG 33s is part of that journey and we have already seen a reduction in fuel consumption and better efficiencies through the technologies the machines provide.

"We're proud to be the first in the UK and Europe to have these. They are two great additions to our already extensive fleet of piling rigs that will keep many clients satisfied."

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