Doran Consulting is providing Civil and Structural Engineering
design services to Hitachi Zosen Inova, the EPC contractor, for the Slough
Energy Recovery Facility, located in the Slough Trading Estate in Berkshire.
This new
facility is part of the larger Slough Heat and Power Station, and will replace
several of the existing facilities. The site is located within an existing site
on a busy industrial estate and space is very limited.
The new facility will process up to 438,000 tonnes of Waste and Refuse Derived Fuel (RDF) per year, and will bring the site total up to 558000 tonnes per year. The new facility will produce an average gross electrical output of 40MWe, and will also generate steam and hot water for use within the Slough Trading Estate.
This is a brownfield site with shallow layers of made ground and Langley silts, over taplow gravels. Due to the heavy loads and settlement sensitive foundations, the foundation solution chosen has been raft foundations slabs on ground improved soils. The ground improvements solution used was Controlled Modulus Columns (CMC). The site poses significant challenges for foundation design given its history – Doran have been heavily involved in development of efficient foundation solutions for the main process buildings and waste bunker, which extends 2m below ground. Where deeper foundation have been needed (waste bunker and stack base) and reach the taplow gravels, no ground improvements has been deemed necessary.
The building superstructures are complex structures, with long span roof solutions and with several building movement joints detailed between structures. Due to the nature of the ground conditions and water tables, it was decided to limit the depth of the waste bunker pit which led to the requirement for a raised tipping hall floor and associated access ramp. Doran have designed the superstructure elements for the Tipping Hall, Waste Bunker, Administration Block, electrical Rooms, Ash Bay, Workshop and Turbine Hall along with several smaller external structures.
Externally, there is an extensive network of roads and hardstandings, including a gatehouse with weighbridges for incoming and outgoing vehicles. Due the to site restrictions all end user vehicle routes and construction plant were Auto-Tracked to ensure safe access into and through the site. This included the access ramp.
The scheme also has a complex network of underground services including fire mains, drainage and various conduits for power and data across the site. Also as this is part of an existing live power plant several existing substantial underground (and overground) cable ducts where locate around and through the site. All of the existing and new underground services have been modelled in 3D for very necessary coordination purposes.