CA Drillers Case Study

London City Airport – (BAM Nuttall)

CA Drillers worked with BAM Nuttall to deliver concrete cutting and sawing services for the airport’s development project. Our job required precise operations in challenging locations, which we achieved on time and with high-quality results, earning us to be shortlisted for an award by The International Association of Concrete Drillers & Sawers.

Due to tight schedule constraints centred around the piling contractor, a daily requirement existed for cutting 80 linear metres (600 mm / 700 mm deep). To meet this demanding timeline, we had to consider installing 40 metres of track at a time with two saws operating concurrently. This was achieved while working from a barge and implementing rigorous water management measures to contain the substantial amounts of water/slurry generated, as, for environmental reasons, it was imperative to prevent contamination of the water within The King George V Dock.

Our cut line was positioned 200mm above the water level, adding significant complexity, particularly since we had to cope with the constant motion of the working barge. Another challenge we faced was that the protective measures used had to be removable daily to accommodate the arrival of the night barge, which was tasked with lifting the cut concrete sections.

Our final solution involved the installation of a 150mm steel guttering system beneath the cut line. This system was installed in 20m sections in both directions, each with a very slight incline, leading into a specially designed container. The resulting waste water/slurry was then pumped into 1000-litre IBC containers located on the barge. These were removed each evening for recycling through a silt buster.

Ardmore Construction – The Old War Office

CA Drillers team were involved in the esteemed restoration project at the historic Old War Office, an iconic site nestled in the heart of Westminster. As the project progressed, our team expanded, reaching a robust strength of 60 skilled operatives during its most demanding phase.

Our extensive scope of work showcased our versatility and expertise in a variety of challenging tasks. This included the diamond drilling of substantial sump pits in the basement areas, complemented by the advanced use of Brokk demolition robots for efficient break-out operations. In the swimming pool area, we undertook precise core drilling to accommodate lighting installations, blending functionality with aesthetic considerations.

Furthermore, our team formed builders’ work openings, employing both hand saws and track saws, coupled with stitch drilling techniques to avoid overcutting. Followed by the installation of lintels was carried out with across all levels, reinforcing the framework of the building. In adherence to stringent health and safety measures, we implemented control measures in our work areas which included full tent enclosures, chapter 8 barriers for demarcation, and dust cubes for effective extraction of any dust generated during our operations.

Our responsibilities also extended to complex tasks such as forming rainwater pipes, a challenging process that began at the roof and involved cutting and breaking through walls and slabs, down to the fourth basement level. Additionally, we were tasked with the intricate chasing of electrical conduits within the ceilings, slabs, and walls throughout the entire building.

A particularly challenging aspect of our work involved the wire saw removal of steel-plated, bomb-proof walls encircling the building. The scale and diversity of our work package not only demonstrated our technical prowess but also our dedication to preserving and enhancing a building that is a symbol of British heritage. CA Drillers takes immense pride in having played a pivotal role in the restoration of this venerable landmark, contributing to the conservation of its rich history and architectural grandeur.

Riverlinx CJV (BAM Nuttall Joint Venture) – Silvertown Tunnel

CA Drillers’ first project involved the deconstruction of the river wall. This challenging task required the implementation of vertical stitch drilling from the landside to sever the wall into detachable sections and subsequently be lifted out by the aid of Riverlinx machines. To ensure the River Thames, located underneath, remained free of slurry produced by the drilling and sawing, strict water and slurry control measures were employed.

Following that, we performed a series of operations on multiple areas on site. We have carried out floor sawing activities critical for initiating the open-cut procedure of the tunnel’s construction. Wire sawing was also conducted on existing UAE structures. Furthermore, we carried out a large quantity of pile cropping, we trimmed the pile tops to the necessary height using an effective combination of track sawing and Brokk demolition. It was essential that we was to retain the rebar within and not cause any damage, therefore the track sawing and Brokk activities was carried out with due diligence as to negate affecting the integrity of the rebar.

In addition, we was awarded the scope of works to demolish the Victorian dock wall which obstructed the trajectory path of the tunnel. For this, we employed a Brokk 400 & Brokk 800, to carry out the heavy-duty demolition task. More recently, we were involved in the headwall cut and carve operation. This operation was vital to prepare for the Tunnel Boring Machine (TBM)’s departure from Silvertown to Greenwich. This stage was a pivotal moment in the project, as it is when the TBM made its initial breakthrough at Greenwich after setting off from Silvertown, effectively forming the initial tunnel wall. In order to facilitate the Tunnel Boring Machine (TBM)’s successful exit, we employed a drilling and sawing approach.

This involved creating a series of drill holes around the circumference of the TBM machine and making vertical track saw cuts. The primary aim of this intricate operation was to weaken the structural stability of the wall. By doing so, we enabled the TBM to successfully penetrate and bore through the wall. This operation required meticulous planning and flawless execution, all of which were crucial in ensuring the TBM’s successful journey to Greenwich. We was provided short notice and time frame to start and complete. We received the phone call on a Friday with the intent to mobilise site on the Sunday and all works completed within the time frame of Wednesday. This achievement was a testament to our team’s dedication, expertise, and commitment to delivering high-quality work on schedule. (Please see pics below of the headwall cut and carve).

BAM Construction – Space House

At the onset, C A Drillers undertook specific assignments for the Space House project, which included making track saw cuts on 48 concrete T units within PAYE’s yard. These intricate tasks demanded heavy-duty cutting and drilling. Each unit required a 3m x 450mm deep track saw cut, a 3m x 750mm deep track saw cut, and a central stitch drill to separate the 3m x 750mm x 450mm section.

Once cut, these units were lifted by the on-site crane and redistributed. Due to certain time restrictions, PAYE made accommodations for additional T units in the yard, consequently amplifying the productivity expected from CA in order to ensure compliance with the project’s schedule. Despite these demands, the team completed the tasks within the set timeframe. Following this initial phase, CA relocated to the Space House site where they were tasked with trimming back lift shaft slabs and executing necessary concrete repairs. Considering the tasks were to be carried out within a lift shaft, operatives ensured the implementation of adequate safety measures to mitigate risk from falling debris.

Activities within the lift shaft were managed with multiple layers of corex to reduce the amount of debris. This careful breakout of the slab also allowed for efficient debris clearance. Additionally, the concrete repair works within the lift shaft were thoroughly documented by the C A site manager through quality assurance documents. These were countersigned by BAM management to verify that all repairs were conducted to their specifications.

In the subsequent stages, C A has carried out a host of diverse tasks around the site. These tasks range from prepping the floors throughout the entire building, lowering the slab level to assist the screed applicators in their work, employing our Brokk robots to chip away at the screed in B2, stitch drilling riser openings across every floor, and creating numerous openings and core holes through both the slab and wall for M&E and ductwork facilitation. Our team continues to work diligently on site, delivering high-quality results and readily accommodating the site team’s requests, irrespective of the given time constraints. For quality control and safety assurance, our contracts manager and health & safety manager conduct either weekly or bi-weekly site visits, undertaking on-site briefings and carrying out safety walkarounds with the C A site team.

FM Conway – The National Art Gallery

CA Drillers were entrusted with a prestigious project at the National Art Gallery for our valued client, FM Conway.

The task involved removing approximately 250 m² of reinforced concrete slabs, each around 300 mm thick, along with a 6 m² wheel wash area up to 2.5 m deep and an old BT chamber of similar size extending to a depth of 3 m.

The challenge of this project lay not only in the depth of the slabs but also in working within an environment housing priceless artwork. To ensure the utmost care, all work was carried out using non-percussive methods to prevent vibrations and disruptions.

Our team utilised advanced equipment, including diesel-powered floor saws, diamond track saws, and precision diamond drilling tools.

Throughout the project, vibration levels were closely monitored by the gallery’s team, ensuring the safety of the artwork.

CA Drillers successfully managed and completed the project on time and within budget, demonstrating our expertise in precision slab removal.

It was a privilege to contribute to such a prestigious project and showcase our capability in delivering meticulous, non-percussive concrete removal solutions.

Tottenham Hotspurs FC – Keltbray

CA Drillers played a pivotal role in the first phase of the demolition package, working in collaboration with Keltbray as part of the enabling works for the construction of a prestigious new hotel at the Tottenham Hotspur football ground.

Our scope of work involved precision saw cutting of approximately 700 linear meters of reinforced concrete, spanning slabs at ground level, lower ground, and basement. These slabs ranged in depth from 600 mm to 1 meter, with substantial supporting beams extending up to 2.5 meters thick.

This project posed unique challenges, as it had to be meticulously coordinated around the busy schedule of Tottenham Hotspur Stadium, which regularly hosted Premier League and European football fixtures, along with a diverse range of high-profile events. Maintaining progress while ensuring minimal disruption required careful planning and adaptability.

Labour fluctuated between 2 to 10 operatives, depending on the release of works, but our highly skilled team remained agile and efficient throughout. We employed precision cutting techniques, including track sawing, stitch drilling at corners to prevent overcuts, wire sawing, and plunge wire sawing. With up to eight operatives on-site daily over a 12-week period, we successfully completed the works on time and within the programme, demonstrating our expertise in complex demolition projects.

Erith Group – 105 Victoria

CA Drillers worked on a significant project at 105 Victoria, working in closely with the Erith Group to safely perform a variety of demolition tasks, including intricate cut and carve operations. This includes the stitch drilling of pile openings to a depth of 1.5 meters and the subsequent lifting of large segments using A-frames.

We also carried out track sawing to form trenches that are 1 meter deep, which were then efficiently broken out using a pair of robust Brokk 400 machines. Our expertise extended to diamond drilling, creating 600mm diameter holes to a depth of 600mm, which was then broken back to create slots for the installation of new steel wailers.

Additionally, we have undertaken tasks involving track sawing for creating corner holes and employing Brokk machines for demolishing sections of a small roof. Furthermore, the operatives used the specialised munching jaw and sheathe attachment of the Brokk machines in removing the roof, effectively reducing the risk of flying debris and limiting vibration transmission through the structure.

Our ongoing efforts include extensive track sawing and floor sawing in the basement levels’ structural slab. This range of work undertaken at the site reflects our standing as a leading specialist drilling and sawing company, particularly skilled in cut and carve techniques. This assertion is supported by our track record on this project.

Erith Group – The Bermondsey Project – The Former Biscuit Factory

CA Drillers were engaged by Erith Contractor Ltd to provide saw-cutting and core-drilling services as part of the demolition works at the Former Biscuit Factory site. With years of experience in precision cutting and drilling, CA Drillers played a vital role in ensuring the project was executed efficiently, safely, and within the required specifications. This case study highlights the scope of work carried out by CA Drillers, emphasising the impact of their expertise on the project’s success.

The demolition of the Former Biscuit Factory involved complex cutting and drilling processes to prepare the site for redevelopment.  

One of the key aspects of the project was dowel hole drilling, which involved drilling 7,914 dowel holes at foundation level into concrete pads. This process was crucial for structural reinforcement and ensuring the integrity of future construction work.

Another critical task was track sawing, which allowed for the cutting of reinforced concrete slabs. This method was essential for creating new openings and making structural modifications in line with the demolition plan. Additionally, wire sawing was employed to reduce pile caps and pad foundations. This technique ensured controlled and efficient removal of heavy concrete sections without causing unnecessary disruption to surrounding structures.

In support of the demolition process, beam and column cutting was carried out with precision saw-cutting techniques. This facilitated the safe and effective removal of structural elements. Furthermore, high-level concrete removal was performed using powered access equipment. The process involved saw-cutting and breaking overhanging concrete nib sections at height, which required skilled execution to maintain safety and precision.

In addition, CA Drillers contributed to foundation and ground floor modifications by performing saw-cutting to accommodate new underground drainage systems. This was a critical aspect of the project, ensuring that the site’s infrastructure could be adapted for future development. Lastly, diamond drilling was carried out to create core drill holes for BWIC (Builders’ Work in Connection) service penetrations. This allowed for the seamless integration of mechanical and electrical (M&E) services into the site’s redevelopment plan.

Project Impact and Conclusion

The expertise of CA Drillers ensured that all cutting and drilling operations were executed with precision, meeting the required safety and structural standards. By utilising advanced diamond drilling and saw cutting techniques, CA Drillers contributed to an efficient and controlled demolition process. Their work not only facilitated the safe deconstruction of the Former Biscuit Factory but also played a crucial role in preparing the site for its next phase of development.

The success of this project underscores the importance of specialized contractors in large-scale demolition and redevelopment efforts. With a commitment to precision, efficiency, and safety, CA Drillers continue to be a trusted partner for complex cutting and drilling projects across the construction industry.

MACE – Woolgate Exchange

CA Drillers were engaged by Mace to deliver the Builder’s Work in Connection (BWIC) package, playing a crucial role in facilitating the construction process. As the project evolved, their involvement expanded to encompass a variety of specialized tasks aimed at ensuring the seamless execution of the development.

One of the primary aspects of their work included soft demolition and strip-out operations. This involved the removal of existing high-level beam finishes, including insulation as well as the dismantling of redundant rainwater pipes. These preparatory works were essential in clearing the way for new structural and service installations.

Another key component of their scope was the formation of openings, which entailed the creation of gulley openings and the installation of new gulleys. Additionally, overflow openings were formed to enhance drainage efficiency. A particularly intricate task involved cutting approximately 110 castellations, comprising various shapes such as holes, squares, and rectangles, through high-level beams to accommodate service routes.

Further contributing to the structural preparation, CA Drillers undertook steel beam polishing within the atrium area, ensuring the beams met the required aesthetic and functional standards. Additionally, they were responsible for drilling operations necessary for the installation of earthing pits, a critical element in electrical grounding and safety.

Specialised diamond drilling was also carried out to facilitate service penetrations within the BWIC package. Furthermore, CA Drillers managed infill works, particularly in concrete applications, to support structural modifications and ensure stability.

The team played a significant role in in-situ concrete works, constructing gantry bases, encasing columns, and pouring lift pit bases. These activities were vital in reinforcing the structural framework of the building. Their expertise extended to structural steelwork, where they were responsible for the fabrication and installation of new beams and columns, contributing to the overall integrity of the construction.

To maintain safety and stability during the works, CA Drillers implemented back propping measures, providing temporary structural support where necessary. Additionally, they carried out scabbling and planning to prepare surfaces for further construction activities, ensuring precision and adherence to project specifications.

Through their extensive range of capabilities and commitment to high-quality execution, CA Drillers played a pivotal role in supporting the successful completion of the project.

Morris & Spottiswood Ltd – 33 Old Broad Street

CA Drillers were engaged to execute the builders’ work package in collaboration with Morris & Spottiswood as part of the major refurbishment and CAT A/B fit-out of 33 Old Broad Street. Their responsibilities encompassed a wide range of tasks essential for structural modifications, service integrations, and overall site efficiency.

A significant aspect of the project involved creating vertical and horizontal openings through brickwork, blockwork, and reinforced concrete to facilitate service installations and access routes. This was accomplished through precise saw cutting and stitch drilling techniques. To ensure the structural integrity of block and brickwork penetrations, CA Drillers also supplied and installed prestressed concrete lintels. Additionally, core drilling was carried out in both vertical and horizontal orientations to form penetrations for various building services.

Another crucial responsibility was the installation of a temporary propping system to support the loading bay, allowing it to accommodate bulk deliveries safely. Furthermore, CA Drillers played a key role in constructing reinforced concrete plinths, which included the supply and installation of shuttering, concrete pouring—either by hand or pump—power floating, and the final striking off of the surfaces.

The scope of work also extended to soft stripping, which involved the removal of redundant services, tiling, and steelwork. Where required, block and brickwork infills were installed to seal redundant openings. To seamlessly integrate the building’s utilities within its structure, vertical and horizontal chases were formed.

Beyond these specialized tasks, CA Drillers provided general labour across the site to maintain tidiness and assist with the relocation of equipment and materials as needed. Additionally, they managed the supply and organization of skips, ensuring that waste materials were efficiently removed and that the site remained clear of debris.

Through their expertise and meticulous approach, CA Drillers played a vital role in facilitating the successful completion of the refurbishment project at 33 Old Broad Street.