Engineers for a major new seaside leisure scheme in Blackpool solved the challenge of concealing an existing sewer by specifying Leca® Lightweight Expanded Clay Aggregate during groundworks for the £13.5 million ‘Central Gateway’ project.
The new multi-activity park at Seaside Way was built on former railway sidings and land adjacent to Blackpool Football Club.
Early in the scheme, PSA Design, of Longridge, Lancashire; Consultant Engineers to client Blackpool Borough Council identified the need for a lightweight fill capable of concealing and existing large diameter sewer, while keeping loadings to a minimum.
After originally considering polystyrene block, PSA’s geotechnical team decided that Leca® Lightweight Expanded Clay Aggregate would provide a more convenient and quicker solution.
Additionally, because Leca® Lightweight Expanded Clay Aggregate weighs just one seventh of traditional quarried aggregates, it also met the requirement to limit any additional loadings when used to increase the ground height along the length of the sewer.
In all, some 360 m³ of Leca® Lightweight Expanded Clay Aggregate 10-20mm was delivered to site and loose tipped adjacent to the void, before being placed using the bucket of a 360° excavator, which was then used to compact the aggregate in one metre layers, in just three passes of the tracked vehicle.
The use of Leca® Lightweight Expanded Clay Aggregate provided a lightweight and speedy solution with the whole task completed in just two days. Additionally, material deliveries involved just six 60m3 high-sided articulated tipper movements, considerably less than would have been required with other fill materials.
Part of Blackpool Masterplan, the Central Gateway project provides new public recreational space in the heart of the resort. A new three lane highway links the M55 motorway with key attractions within the resort and is set amongst large areas of contoured parkland, spectacular illumination, footpaths, cycle paths, a children’s play area, all-weather pitch and secure landscaped public car parking. The most striking features are two 20 metre high climbing towers, one of which spells out the name ‘Blackpool’.