Customer:St Paul's Developments
Value: £4.7 million
The former coal-fired power station, located on the banks of the River Tyne, was operational from 1951 until its closure in the 1990s.
All above ground structures had previously been demolished to ground level, although the foundations and underground structures and culverts remain.
VHE carried out remediation and reclamation works, which comprised the break-out and processing of the complex substructures on the site along with the remediation of 15,000 cubic metres of hydrocarbon contaminated materials, of which 7,000 cubic metres were treated by bioremediation utilising the services of our in-house technical division VHE technology. Works were undertaken around a major substation and under multiple overhead cables. VHE grouted the underground structures that were too large to remove and new construction utilized these as foundations. Other structures were left in place.
The bulk earthworks carried out involved a cut and fill operation of approximately 350,000 cubic metres to achieve the final ground levels, together with clean capping over the majority of the site. This included more than 160,000 tonnes of concrete, building rubble and reinforcement either in-situ or stockpiled by the demolition contractor together with 55,000 cubic metres of unstable river valley silts and sands, 3,500 tonnes of mangled reinforcement still encased in concrete and 7,000 cubic metres of soil heavily contaminated with oil, petrol and diesel.
Lime stabilisation was used to reduce the moisture content of marginal material to render it suitable for re-use.
The reclamation strategy was developed with a view to maximising the amount of material to be re-used on-site. Demolition rubble, concrete floor slabs and made ground are used to fill material following break-out, crushing and screening. There were around 3,500 tonnes of rebar on the site. VHE removed and recycled 50 per cent more waste concrete from the ground slabs than was required in the plans in order to feed the development’s requirement for crushed concrete capping.
VHE also carried out the construction of primary infrastructure access, comprising an adoptable access road with services, surface water drainage outfalls and a foul pumping station. VHE installed three major outfalls into the tidal influenced Tyne including the in-situ relining of an existing culvert to take the weight of major noise bund.
The scheme provided development plots, estate roads and recreation areas to enable a 500 unit housing development on this 19 hectare site.