Lumiere LLP - Carillion

Scheme Outline: Structures – City Centre Environment Excavation, 14 metres below ground level to construct a 3 storey basement underneath a 50 storey tower block. Excavation 40,000m³, extensive de-watering 11 metres below standing water table, temporary works design & construction in a City Centre environment, reinforced concrete, ring beam construction involving significant and complex insitu concrete works, installation of piling and foundations.

Early Contractor Involvement
The contract was an ECI scheme which Hewlett worked on with the client for a year before contract commencement; during which the cost of the project, the design and value engineering were all built up in conjunction with the client as was the development of the supply chain.

Client: Lumiere LLP/Carillion

Value: £9.7 million

Additional Details

• Site clearance and enabling works included demolition, temporary works and formation of new retaining walls to restrain adjacent buildings. Installation of secant and bearing piles plus ground anchors. Excavation, propping, dewatering of excavation, and construction of concrete capping beam plus installation of base slab and waterproofing. Construction of all highway and infrastructure works.

• Excavation was a complex issue with 40,000m³ to be removed from site under testing urban conditions.

• All excavations were carried out using Hewlett plant and equipment, all workforce and management full time employees of Hewlett Ltd.

• Waterproofing of basement areas was a significant technical challenge using bentonite matting system.

• Significant traffic management in a City Centre project to enable traffic flows on main routes adjacent to the site boundaries.

• Dewatering was a major issue. Hewlett worked with the EA to get Discharge consents for up to 601/s to local drains.

• Massive amounts of concrete were placed to construct the base slab and capping beam on top of secant piles. A 1.8 metre section and reinforcement up to 240kg/m³ in complex configurations. All concrete, dewatering, and substructure works were completed using Hewlett’s own workforce.