Heavy cranage and other plant being used at a large specialist reinforced concrete construction site - Carney Construction

Durleigh WTW

Project overview

Durleigh Water Treatment Works project is to carry out the structures rebuild of the existing WTW at Durleigh for Wessex Water. This includes RC tanks, building bases, walls, chambers, plinths, wall extensions, single sided wall construction, slopped and profiled screeds.

Key info

  • Contract start date: October 2019
  • Planned completion date: October 2020
  • Total value: £1.2 million ongoing

Carney Services provided

Under a NEC contract Carney Construction acted as the Civils Contractor looking after all FRC works at the site.

Total current value £1.2million ongoing.


1. Safety

During the delivery of the project the COVID-19 pandemic occurred, this heavily affected the works and required extensive re-working of controlling methods of transport to site, site works and programmes. Carney Construction worked with the site team to make sure that additional vehicles were available, new systems of working and using the site were developed and followed onsite and suitable changes made to video conferencing instead of site meetings were made to reduce the risk of infection of both Carney staff and all other site stakeholders.

Carney have purchased specialist safe access steps that can suitably satisfy a difference of over 5m in height, this has removed the need for ladders for access onsite and reduced the chances of accidents accessing the deeper tanks.

Peri – single sided formwork was used as a cast in anchor bolt could be used in the kicker, this is a suitable method of reducing the requirement for drill in anchors which require heavy testing to be proven safe, this also sped up the construction of the low lift pump area and allowed better control of construction joints (reducing the chance of shrinkage cracking).

2. Quality

A high quality of concrete finish was required throughout the works at Durleigh to prevent excessive growth of algae etc associated at the WTW, managing this throughout the construction process we adapted to utilise Wessex Water paperwork and procedure where requested but otherwise utilised Carney ISO accredited quality management systems.

Throughout the works snagging was completed as became available and all re-working was completed with approved materials to specifications under combined Wessex and Carney ISO quality procedures. There have been no delays & 100% signoff of completed structures currently being developed onsite.

3. Productivity

Carney Construction have amended site labour and resource requirements to suite the clients needs throughout this project. This has included focusing additional resource to some areas allowing early release for other contractors to commence works earlier then the original programme showed (after COVID delays taken account of).

Carney have also shown the ability to manage significant one off pours, with the largest single pour of over 800m3 being the largest in the region apart from Hinkley Point for the month of July. This pour was completed on time and to a high finish quality by means of power float despite high summer heat challenges.

In some instances Carney have incurred additional cost to improve the programme at no additional cost to the client. This is based on mutual assistance and co-operation in incorporating improved constructibility measures within the permanent works designs.

4. Conclusion & Summary

Carney have been integral in developing this new scheme for Wessex Water and have proven a collaborative approach to both design change and changes to method of working within the industry caused by COVID-19. The following challenges Carney have helped Wessex to deliver this project to the programme and cost requirements:

  • COVID-19 pandemic management systems effectively managed, no cases of spread onsite.
  • Instances of poor concrete supply have been managed onsite, maintaining quality by increasing construction points where necessary.
  • Re-sequencing works around key items of M&E equipment deliveries.
  • Co-ordinating and sharing of crane and other key site resources suitably with other site operations.
  • Maintaining site access for existing site operations and controlling contract works such that disruption to key stakeholders has been avoided.

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