Harworth Group
£2.6M
November 22 to September 23
The Ironbridge Power Station regeneration project – Harworth secured planning approval for the regeneration of the former Ironbridge Power Station in Shropshire. The 350-acre site in June 2018, before which it has been used for electricity generation for over 80 years.
Located less than a mile from the Ironbridge Gorge World Heritage Site, the development is bordered by the River Severn to the north and an extensive area of ancient woodland to the south. In addition to new homes, plans for the development include a retirement village, offices and light industrial units, retail, a new primary school, allotments and sports pitches, while the former power station’s 1930s pumphouse will be retained and transformed into a flexible space for community and leisure use.
JFHR Scope of Works Included
- Complete and get approval for all the required working documentation for the project.
- Agree the site perimeter boundary line, and standoff from trees along the boundary
- Agree site arrangements and location of welfare.
- Complete installation of welfare facilities
- Agree discharge points for foul and discharge of water to foul and surface locations.
- Complete a condition survey of the access roads and works are.
- Service location survey around key buried services located on site and site boundary.
- Installation of TPO fencing as required along tree line at the northern boundary.
- Complete vegetation clearance works and tree removal on non TPO trees.
- Agree all ecological measures are in place and implemented where required. Inspection of ponds for Newts and watching brief of pond when dewatered by ecologist is completed in-line with requirements.
- Obtain approvals for the required permits from the Environmental Agency and for discharge of waters on and off site and agreed locations.
- Ensure any monitoring boreholes are clearly marked and protected with fencing.
- Ensure that all excavation works are completed in accordance with the MMP and specification for the site.
- Complete compaction trials using representative materials on site
- Trial pitting works were completed within every grid square, this allowed JFHR to prevalidate and understand the depths of the natural ground across the entire phase 2 site.
- Turnover of suitable soils and reengineer back into the ground in accordance with the earth works strategy
- Asbestos cement was also found within the concrete structure and used for shuttering. JFHR excavated the ACM’s and handpicked them. The soil was then tested and reused as fill material.
- Testing of each layer placed including CBR testing of the final cover layer of 6F2. This was placed at 300mm not 200mm due to not being able to get a 5%cbr on the 200mm cover.
- Breakout of concrete structures, these include Water flutes that lead to the cooling towers, water cooler tower basis, P19 forebay a large water body that was used for the 2m diameter cooling pipes, Sewage treatment works, tank basis, existing water cooler towers that had not been removed during demolition and removal of existing water pipes surrounded in concrete.
- Processing & crushing of concrete to produce a recycled 6F2 (reused on site)
- Removal of concrete piles, These were placed directly under the water-cooling tower base to add support for towers, JFHR excavated all pile caps and either removed the entire cap or broke them off below the required depth as specified in the specification.
- Placing 6F2 crush material at the retaining wall in accordance with the TWD
- Construct a road for the delivery of a new sub-station
- Grouting up of 4 2m diameter water cooling pipes that lead to the boiler house.
- Movement of existing stockpiles used for fill or relocated to the wider site.
- Construct settlement pads and monitor them for the duration specified in the spec
Challenges
- Double the amount of concrete buried within the ground.
- Rain, snow, and icy working conditions proving to be difficult and prevented us from working.
- Unable to get a 5% CBR on the specified depth of 6F2 placed so this was increased
- Receiving confirmation on the removal of the 26 oiled filled cables running from north to south on the site and arranging for NG to spike the cables.
- Locating W6 discharge pipe as no one new its location, this had to be protected• Finding asbestos cement in areas of the site, slowed the works down due to having to handpick the ACM.s
- Due to the size of the site, we had to crush concrete on areas where earth works were to take place, this meant double handling of crushed 6F2 material.
Successes
- In some areas of the site natural ground was shallow resulting in not having to excavate the full depth of 2m this resulted in making up lost time.
- JFHR managed to save money on the testing frequency that also allowed us to progress the works slightly quicker.
- Working alongside a very skilled competent team.
- Fully compliant with the specification
- Built a great relationship with the client that has led to further works
- Negotiated the testing rescheme for the mass stone fill