Building fourteen million square feet of office space and retail malls on such a small footprint as well as simultaneously creating the infrastructure of roads and associated utilities, public transport connections, pedestrian circulation and parks, has provided both a challenge and an opportunity. The experience gained at Canary Wharf is being replicated on other projects in London with great success.
As an example, Canary Wharf has the benefit of extensive water frontage. The use of barges to bring construction materials to site and transport waste materials off the site has had an extremely beneficial impact on the construction process while mitigating the effects of construction traffic on local roads and in turn on the local community. We have also used the water to build an extensive network of temporary piled “water roads” to allow road traffic access to each construction site. An on-site floating batching plant provides concrete to our projects utilising the latest technology in concrete production. The use of aggregate supplied by barge has eliminated substantial delivery traffic on local roads and minimised on site travel distances, while offering the benefit of guaranteed supply and high quality.
Temporary cofferdams have been extensively deployed as a site reclamation method. These have the benefit of allowing the construction of buildings with deeper basements and hence the consequent efficient utilisation of above ground space. Improving construction methodology has always been a goal of our construction team. Working jointly with consultants and contractors we have developed the use of high capacity base grouted piling techniques which later evolved into high capacity CFA piling. This new method has further improved the speed of construction and, by using saturation piling under the most loaded area of the building, has allowed added flexibility in the positioning of the vertical structural elements. This in turn has permitted flexible floor layouts to the benefit of potential clients unaccustomed to the option of participating in the design of the building at the time of lease negotiations. Similar ideas will benefit projects elsewhere in London; other ideas, such as reusing existing piles to provide support to the newly designed buildings could prove of significant benefit in time and cost saving. The search for better efficiency in the construction process has lead to the development of slip form methodology for the construction of concrete cores. This method, whereby the core is erected first and the balance of steel structure follows, has maximised the efficient use of cranes and shortened structure erection time by up to 25%.
While most construction companies positioned in a competitive market cut costs on preliminaries by short-changing on the number of hoists and cranes, Canary Wharf Contractors maximises the efficiency of movement of materials as time gained in the construction process is rewarded by early release of the building for occupation.
Our computerised delivery scheduling system allows us to co-ordinate vehicle arrivals on multiple projects, eliminating downtime as a result of materials shortages. We use on site marshalling centres to control the numbers of vehicles coming on the project at any one time. It is worth pointing to the expertise accumulated by CWCL in managing the construction of a number of high-rise structures in proximity to railways, as well as building two stations for the Docklands Light Railway while these railways were in full operation. After the Jubilee line was put into operation, the design and construction of Canary Wharf adjoining structures has taken into consideration the special requirements associated with the station and tunnels and developed into a working relationship with operator Tube Lines. Such experience is invaluable for any project developed adjacent to an operating railway.
To conclude, the way construction logistics has been employed on Canary Wharf projects, as well as our innovative approach to construction processes, demonstrates the capability of CWCL undertake complex construction assignments.