The complexity of the logistics challenge at T5 cannot be understated. Every day, the site consumes 5,000t of aggregate, 650t of portland cement, 260t of pulverised fuel ash (PFA), and 313t of rebar.
From an early stage, it was obvious that if there were variations in supply caused by non-controllable factors, there would be a major impact on the flow of goods to the site.
This would have a major effect on productivity.
It was also realised very early on that due to several factors, including the earthworks stockpiles, the size of the structures and the location of the project (between two runways on each side, an operating terminal on one end and an operating road on the other) that space onsite would offer a maximum of two days (more, often less than that) for materials and plant storage.
As a result, it became clear that logistics centres would play six key roles, explains T5 demand fulfilment manager Nigel Harper.
'They would shield the site from variation resulting from road transportation; confirm that inbound goods meet quality and quantity requirements; facilitate the manufacturing of engineeredto-order materials (rebar);
provide a local buffer of raw materials for final processing (concrete); enable better matching of deliveries with actual site demand; and ensure that delivery personnel conform to security requirements, ' says Harper.
Given the intensity of flow through the logistics centres, it was decided to use two - Colnbrook and Ascot Road.
Colnbrook, a new facility developed at a cost of £6M by Foster Yeoman, provides the T5 site with its railhead for the supply of all bulk raw materials.
Hauliers Mendip Rail (a Foster Yeoman joint venture with Turrworks) and EWS bring the materials in.
Rebar and concrete is then processed at the other part of Colnbrook, developed at a cost of £20M by BAA, with formwork and pile cages being manufactured or consolidated at Ascot Road.
Raw materials for concrete are delivered from Colnbrook to the site based on a 'pull' from the batching plants.
Similarly rebar, formwork and pile cages, engineered to order, are detailed, fabricated, assembled and delivered with a lead time of five days.
Inbound materials into Colnbrook are managed using minimum and maximum inventory levels. When the inventory at Colnbrook falls below a certain point, additional materials are pulled from the suppliers.
'To date, the results have been noteworthy and we believe set the foundation for future development and use at T5 and within the UK construction industry, ' says Harper.
By using two logistics centres, Harper's team has cut the storage for concrete materials from three weeks to three days, resulting in space savings of 3,000m 2and knocking £600k off the original cost plan.
Piling for the T5B building has been installed on programme with a cost reduction of 10% overall. Steel fixing costs associated with the railbox have been cut by 35%.