As one of three surfacing framework providers in the network community, Aggregate Industries has been delivering major improvement projects, including resurfacing the Dartford Crossing’s Queen Elizabeth II Bridge, for Connect Plus Services who project-managed delivery of the scheme.
Principal supply chain partners were: Aggregate Industries – surfacing; Power Plane – milling; WJ South – road marking and studs; Techjoint – waterproofing; Chevron – traffic management.
The project objective was to reduce the number of pavement interventions on the network, so minimising disruption to traffic flow. On average, 75,000 vehicles use the four-lane crossing daily, making it a vital transport link for the South East and national economies and a highly congested area of the Network. The bridge deck is subjected to high volumes of channelized traffic and heavy loads.
Effective partnership working enabled the development of the right solutions to complete the £1.9m resurfacing project in July 2015; two weeks earlier than originally programmed and within budget.
The binder and surface courses laid contain a polymer modified binder designed for durability; developed for us by bitumen specialist, Nynas. The surfacing has a high rut resistance and been proven on previous schemes in heavily loaded or highly trafficked areas such as the Dartford West Tunnel.
We value engineered the project by assisting the Client in selecting high performance materials to deliver long life solutions and whole life costs. The resilience of the structure has been improved and the surfacing life extended for up to 10 years, minimising the need for related maintenance intervention. The need for future works under short notice emergency closures has been reduced providing potential savings of £800,000 over the life cycle of the contract.
To foster non-adversarial working, the Client has invested in collaboration training for community members covering: leadership development, accredited framework facilitators, collaborative innovation forums and community inductions focusing on the way we work. 360 degree meetings (run by framework facilitators) identify what assists or hinders the contract and findings are disseminated to the wider community. Our Framework Manager has been trained as an accredited facilitator to lead these meetings.
Planning and programming
We used our local knowledge to highlight other strategic projects happening simultaneously in the area (Dartford Freeflow Congestion scheme, Junction 30 upgrade and TfL’s resurfacing of the Blackwall Tunnel approaches). Following a planning meeting with the Client and TfL, the delivery team adjusted the programme to bring forward the start of our works by two weeks to avoid clashing with the Blackwall Tunnel closure. We therefore reprogrammed our resources to maximise efficiencies using multiple gangs/shifts to deliver the project.
Contingency planning with our internal supply chain enabled us to maximise the amount of work undertaken in the tight working window. Certainty of supply was guaranteed by assembling all labour, plant and materials at a holding site at Essex Point each night before transferring to the bridge. A new binder tank was installed at the back-up Greenwich plant to allow the correct asphalt material to be manufactured at all three plants.
We worked with the Client and supply chain partners at planning stage to agree a TM plan to minimise disruption to the public, by applying lean shift plans and phasing all construction elements in stages. By undertaking the resurfacing at night, day-time use of the bridge was left unhindered. One lane running ensured traffic flowed throughout the duration of the works, avoiding any full closures.
The contract required the removal of 80mm of surfacing without compromising the waterproofing; complicated by 'rutting' in the existing surface. Power Plane’s planers (fitted with offset laser levelling) achieved this by using the same reference point for levels where there was no deformation; allowing the work to be completed without delays to survey the bridge levels or damaging the structure.
Environment & sustainability
Environmental impact was reduced by recycling 60% of the asphalt planings. Base/binder asphalts laid contained 10% RAP, diverting the planings from landfill and displacing the need for virgin aggregates. Materials were manufactured and delivered through our local Purfleet and Northfleet asphalt plants to minimise travel distance for the haulage fleet. A non-tipping truck with higher carrying capacity (28t compared to the standard 20t) resulted in fewer vehicle journeys, less noise and pollution.
Partnership performance was monitored using a balanced scorecard, which scores seven areas (1-12) from each participant’s point of view. This identifies best practice so the resulting benefits can be shared by all parties. An Action Plan is produced to develop areas for joint improvement and deliver continuous improvement. The scheme achieved the highest score to date on the M25 contact from over 60 balanced scorecards delivered.
This vital part of the network now provides an enhanced experience for road users and requires minimal maintenance for the next 10 years. Through proactive partnership working, we have been able to plan and manage the works safely and to a high standard. The project has delivered mutual benefits to all parties through sharing knowledge, skills and expertise, transferring learning and best practice and identifying innovative methods and technologies to drive efficiencies on future projects.
Connect Plus Services
Value of Works: £1.9m
The project was delivered two weeks earlier than programmed and within budget.
Supreme binder laid designed for long life and minimum intervention.
Exising carriageway was removed to a depth of 80mm using innovative offset laster levelling.
Minimum future pavement interventions provides savings of £800,000 over the life cycle of the contract.
The scheme achieved the highest score to date on the M25 contract.
We were impressed by the well planned and fully integrated team that had been put together to deliver this complex resurfacing project. The team clearly thought about the importance of partnership working and used lean principles to develop their systems and processes.