Careys Civil Engineering has been contracted to act as principal contractor and significant contributor on crucial stages of the project to create a global retailer’s new European headquarters, located in Watford.

Our scope of works includes the construction of the building’s 12-storey concrete core and the excavation and creation of a 10m-deep, two-level basement, which will be used for car parking facilities.

Careys helps to construct leading retailer’s new European headquarters

Phase one of this project to construct a new European base of operations for an international retailing firm in the town of Watford – situated 24km northwest of central London – has consisted of conducting the early works for a two-level basement. This involved:

  • Creating a basement perimeter piled wall
  • Constructing a capping beam
  • Building a section of top-down slab
  • Excavating to formation level
  • Disposing of construction waste, efficiently and sustainably, off site
  • Carrying out reinforced concrete raft construction

After successfully accomplishing these initial responsibilities, we were awarded the phase two works. This package consists of completing all concrete works – from the lowest basement level, B2, up to the ground floor – construction of columns, and creation of the B1 level slab, line well, ramp and ground floor slab.

We are also responsible for phase three of this project, which entails the construction of the structure’s 12-storey concrete core works.

Our innovative approach and digital expertise improve project efficiency

In keeping with our commitment to deliver work of the highest standards, as efficiently, cost-effectively and safely as possible, we carried out a characteristically meticulous and thorough planning process for this project. This led us to identify several methodologies that could help us to enhance project productivity and effectiveness.

For instance, with the invaluable support provided by the construction engineering and digital experts of in-house Careys Design Team, we devised a value engineering option to increase the reinforcement in the perimeter pile design, in order to allow for a reduction of rebar in the liner walls.

We also were able to amalgamate the design of the temporary propping at capping beam level with the pile design works, which allowed for just one level of propping. This single layer was easier and faster to remove, once the B1-level slab was poured.

Using different methods to operate effectively and considerately on a tight site

Because the site is set directly across from the Watford Junction rail station and sits on a busy intersection, with neighbouring houses and offices overlooking it – we needed to formulate a plan that would permit continued construction access, while causing only minimal impact to our neighbours.

As a result of our in-depth research and preparation process – underpinned by state-of-the-art building information modelling (BIM) data – we proposed the use of top-down construction on the gantry slab section of this project. By pouring the ground-floor gantry slab first, in advance of bulk excavation works, we were able to deploy, maintain and manage a one-way traffic system on the site. This created zero wider impact and played a critical part in limiting the project’s effects on the surrounding residents and offices.

The gantry slab also freed up valuable storage space and provided a location for the temporary site welfare units.

The early use of a tower crane on site was another means that we identified to enable us to operate more efficiently in the site’s limited area. We deployed a crane that was specially designed to be installed on four-plunge columns and a steel grillage. It was also propped back to corbels on the gantry slab. Our design allowed the tower crane to be put in place and operational prior to the commencement of bulk excavations.

Unusually warm summer conditions lead to record efficiency

Weather can often be a hinderance on construction projects – especially in the UK. However, last summer was one of the hottest and the driest summers ever documented in England. The balmy temperatures and lack of rain offered a boost to our programme, helping our works to progress extra smoothly.

In fact, we achieved record amounts of muck removal over the summer period – transporting approximately 33,000m3 of material from the site, which translates to circa 4,000 wagons. The use of the gantry slab, together with the dry conditions, enabled a highly successful muck shift operation.

At the peak of our muck-away operations, we were removing up to 130 loads of material a day. The use of local tipping facilities, a one-way traffic system and experienced Careys traffic marshals all led to our successes.

Sustainability measures help to safeguard the environment

At Careys, we are committed to protecting and preserving the environment. On this project, we dramatically reduced the carbon footprint of the earthworks removal process by transporting the made ground element of the basement excavation to our bespoke Careys soil washing plant, rather than to area landfills.

At our wash plant, the excavated materials were processed to remove contamination and produce aggregates, which were then reused on other Carey sites across London. Rather than sending construction waste to area landfills, we were able to prepare it to be recycled and reused in our other sites across greater London.

In addition, we used natural strata materials excavated on this project to produce an environmental clean cap and working platform over contaminated ground at another nearby Careys’ site. We did this with full Environment Agency approval, under a Claire protocol. By taking this step, we were able to significantly reduce the transport impact of both removing materials from one site and importing them to another – lowering carbon emissions by up to 70%, in the process.

Also, throughout the project, the team has set up, maintained and continually reviewed various types of environmental monitoring. These have included weekly movement monitoring of surrounding roads and structures, load monitoring on the propping system, noise, dust, and vibration monitoring, as well as the use of an on-site weather station.

Committed to taking care of the local community and our people

Additionally, on this Watford-based project, we have demonstrated our ongoing dedication to giving back to the community. The development is within a designated employment area and will form part of the local council’s plan to promote sustainable economic growth and reinvigorate Watford’s employment market by attracting and retaining high-quality office occupiers.

In 2018, there were two site visits from representatives of the Considerate Constructors Scheme (CCS) – a national initiative set up by the construction industry to improve its image and encourage best practice. From the time of the first CCS visit to the second, we went from strength to strength, raising our already respectable score of 40 to 42/50. Indeed, in two categories – caring about appearance and protecting the environment – we earned the scheme’s “exceptional” rating.

From a health and safety perspective, we have worked approximately 130,000 man hours on this project without a serious injury – which highlights our strong commitment to the security and wellbeing of our staff.

To find out more about our experience working with the retail sector, please click here.

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