Cemex are undertaking a major scheme to upgrade the Climafuel infrastructure at their Rugby Cement Plant. Climafuel is a waste derived fuel which is made using household residual and commercial waste. This is processed to produce a clean, non hazardous product. The product replaces 20-60% of the fossil fuels used to heat the cement kilns therefore reducing fossil fuel use and reducing waste to landfill.
Our work on this scheme was the enabling works package, which included demolition of foundations from a former building, drainage diversions and general ground level reduction.
The new Climafuel building is to be constructed over split levels due to the nature of the existing site topography. Therefore the key task for the project is to reduce the ground level which will allow construction of the ground floor slab. The total earthwork excavation is some 20,000m3, which was place elsewhere within the restoration areas of the site.
The site had several services running through it, including surface water, a foul rising main, potable water, comms and both high and low voltage electricity. The comms had been abandoned by CEMEX prior to the works. The surface and foul water were to be diverted as part of out enabling package. The HV and LV had been diverted around the dig, but still clashed with the surface water diversion requiring a crossing.
Work commenced with service location using hand excavation coupled with CAT and Signal Generator. This immediately identified that the 525mm concrete surface water drainage would go through a cable joint pit. Following record checks it was noted as being sensitive and should not be disturbed. We worked closely with CEMEX and their designer to propose an alternative alignment which avoided any excavation work close to the HV, eliminating the risk completely. This allowed drainage works to continue, with some adjustment to manhole locations and alignments. Five new manholes were completed in total. During the works, the drainage system had to remain active, therefore we opted to construct from the downstream connection back up to the tie in point. An emergency overpumping system was on call for the tie in connection.
Excavation works continued in parallel, once services were proven to be abandoned. This used an earthworks team to haul material to the stockpile site, which was levelled with a bulldozer. During excavation, an unexpected risking main was encountered. It was thought to have been abandoned, but was clearly still operational.
We implemented a temporary solution to managing the water from this and again worked closely with Cemex to agree a permanent diversion, placing the main within the existing surface water trench to minimise the amount of additional works required.
The excavation also contained a design and build retaining wall element. This wall was required to provide the required yard area for future works, and retain the car parking at the higher level. The retained height of the wall was in excess of 4m and required a temporary excavation and subsequent backfilling with imported material. We opted to utilise a precast vertical panel system, with the panels cast into an insitu poured reinforced concrete base slab.
Following completion of the main earthwork and civils items, finishing works included new trief kerbing to the car park area, restoration of block paving and construction of a new fence on top of the retaining wall.
Unexpected services were a key factor in this contract, we worked closely with the client and their designers to come up with solutions that worked for both construction, the clients wishes and design considerations. This led to a key safety improvement with excavation no longer taking place under the high voltage cables.
Works were completed on time through extremely challenging weather conditions which led to widespread UK flooding during this period.