“Being located in central London and constantly being surrounded by the public, traffic and residents meant that every single aspect of work on site had to be meticulously thought through.
“When complete, this project will be an essential part of helping Crossrail to make travelling in London and the South East safer. The project will help towards reducing crowding on London’s transport network, most notably the rail network which is projected to have a 10% increase in network capacity.”
Asha Mistry, Environmental Advisor, Costain Skanska Joint Venture
Costain Skanska Joint Venture’s C360 civils project is part of the Crossrail scheme and comprises the construction of reinforced concrete intermediate shafts and headhouses at Mile End and Eleanor Street (including all associated enabling works). It also involves the construction of headhouses at Fisher Street, Stepney Green, and Limmo Peninsula.
The Fisher Street site is located in Holborn, a densely built-up area in central London. The site itself has a footprint of approximately 790 square metres, is very constrained and is situated between listed buildings with a courtyard area to the rear.
Outlining the project, Asha said:
“The latter three sites were awarded to C360 after the project had commenced. The intermediate shafts at all sites provide access to the running tunnels for firefighting, emergency access/egress and general maintenance.
“The site offices used by CSJV at Fisher Street are a Grade II listed building, including basement. A hotel refurbishment is being carried out by McLarens adjacent to the project site. The main building fronts Southampton Row, however, access to the site for vehicles is via a smaller side street. Work at the project site is carried out on a 24-hour basis, seven days a week except Sunday evenings.”
Overcoming the various challenges of working in busy Holborn
Asha outlines the various hurdles encountered with the work, with the main issue being the lack of space at the Fisher Street site:
The hardest challenge was ensuring that the work on site (e.g. noise, dust, increased traffic etc.) did not cause a nuisance or affect the local community. Thankfully, real-time monitoring, early engagement with the local community and regular updates/meetings meant that the community have felt as if they have been kept informed. We have received very few complaints from the public regarding the Fisher Street site, which upon further investigation, were not found to be related to our site.
A separate principal contractor working as part of the Crossrail project needed to use Fisher Street for construction of their Floating Track Slab (FTS) in the tunnels (this is the concrete track slab with a supporting resilient layer or spring system).
In order to pour the FTS, a concrete pumping station had to be installed to pump from the surface down to the running tunnels. Due to the distance the concrete had to travel, very powerful pumps were needed. These pumps had high sound power levels which could potentially impact upon local residents. Additionally, the works had to be undertaken on nightshifts. This was to minimise the potential loss of concrete from delays to deliveries as a result of London traffic.
Reducing the noise
The biggest environmental challenge was ensuring that the noise from the pumps did not adversely impact local residents. We overcame this by constructing an acoustic noise enclosure. A noise assessment conducted by Skanska pinpointed how many decibels would need to be reduced to ensure the site’s noise was below levels stipulated in the Crossrail Act criteria.
The assessment showed that a 20dB reduction at the nearest receptor was required. The final design of the acoustic shed was amended to ensure that this was incorporated. The acoustic shed had deconstruction designed into it – this ensured its removal caused minimal disruption. All materials as part of the enclosure have either been reused or recycled, thus 0% of waste went to landfill.
In addition to the estimated number of site staff expected to use Fisher Street, 150 extra operatives per shift, working elsewhere on the Crossrail scheme, were required to use the site set-up.
The biggest challenge was ensuring the welfare facilities were adequate enough to accommodate the increase in operatives, especially in an area where space is limited. A reorganisation of the site layout and additional logistics, such as daily cleaning regimes were put in place to ensure everything ran smoothly.
How the Scheme makes a difference
Whilst our clients are looking for us to create a sustainable business which will be successful and profitable both now and in the future, increasingly we see that clients and other stakeholders are looking for more than just a constructor. They are looking for companies who are knowledgeable and proactive and manage their activities to provide a positive impact in and around the construction sites.
The Scheme helps to improve the image of construction by having clear guidance on what is expected of a site that has registered with the Scheme. This gives our clients and the public confidence that we really are pushing ourselves to be the best that we can.
As the CCS is such a well-recognised and respectable organisation, it helps gain buy-in from senior management. Even as a general member of the public, the differences that can be seen when walking past registered CCS and non-registered site are very noticeable. We found the experience of registering with the Scheme to be very easy and straightforward – it really couldn’t be any simpler.
Here are just some of the many different examples of best practice Costain Skanska implemented on this project:
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