Crossrail Project - Stockley Flyover, Heathrow

Leca LWA Installation

Crossrail was one of the most significant infrastructure projects ever undertaken in the UK – improving journey times across London; easing congestion and offering better connections. 

For the construction phase of the project, Network Rail, Carillion and Jacobs were responsible for the design, development and delivery of the Stockley Flyover. The flyover is located in a very busy Heathrow Airport Junction area - providing a grade separated rail junction - enabling the facilitation of Crossrail and Heathrow Express service trains, which services trains to and from Heathrow as well as along the Great Western main line. Furthermore, the junction provided new routes from the main and relief lines to Heathrow and London Paddington

A reinforced concrete U – trough was developed to support a new rail line being constructed and this required a lightweight aggregate fill.  LECA® LWA was specified, which offered a reduction in bearing pressure at base and the pneumatic delivery facility offered an effective option for the construction of the U-trough - helping to speed up the project install. 

Over 5000m3 of LECA® LWA (10-20mmR) was delivered and installed for the Stockley Fylover, which took place over a 6-week period – where half of the specified material was delivered through the unique pneumatic Blowing rig and the other half was delivered by walking floor. 

The pneumatic blowing facility was a key feature for Carillion because of extremely limited access constraints to the busy site. This limited access required the pneumatic blowing rig to be sited off site in a carpark of an adjacent building. The distance of the pneumatic blow was in excess of 150 metres but was furthermore compounded by a rise in excess of 6 meters. Due to these access constraints a secondary blower unit was incorporated to assist with the distance and elevation.

To store the material and to allow for a smooth and consistent delivery of LECA® LWA, a stockpile was built on the site, where the pneumatic blower could be quickly re-loaded at site – allowing for the material to be delivered quickly, saving considerable time and resource.

Through specifying LECA LWA, the development of construction of the Stockley Flyover was fast and effective, and this development which still stands strong today is a testament to the success of LECA LWA.