At the M60 Simister Island interchange, the successful removal of four concrete gantries started long before the first piece of concrete was lifted. By digitally rehearsing the demolition in 4D, the Costain team could test the sequence, identify opportunities to improve it, and build confidence in a complex operation before taking it onto the live motorway.
There is little room for uncertainty when working on one of the North West's busiest motorways.
For the M60 Simister Island interchange project, which Costain is delivering for National Highways, the team recently faced a particularly demanding task: removing four concrete gantries spanning a combined 22 lanes of the M60 over the course of two separate weekends, while protecting the existing carriageway and associated highways infrastructure.
The operation formed part of a wider programme of works requiring a full motorway closure. With a planned 33-hour window available for each of the two weekends, every activity needed to be carefully considered, sequenced and coordinated.
For the team, that meant doing more than planning the work on paper. Instead, they built it twice: first digitally, then on site.
Rehearsing the demolition before it happened
Using 4D construction sequencing software, Costain’s team developed a detailed digital sequence of the demolition.
The 4D model brought the three-dimensional construction information together with the planned programme, allowing the team to see not just what needed to happen, but when, where and in what sequence each activity would take place.
This provided a shared view of the proposed operation for readiness reviews with senior leaders, briefings with the construction team and discussions with stakeholders. More importantly, the digital rehearsal provided an opportunity to challenge the planned sequence before work began.
By stepping through the demolition virtually, the team could identify risks and opportunities that may have been less apparent through traditional planning methods, developing a greater understanding between all parts of the operation, from customer to every part of the supply chain, on how the different parts work together.
Making every hour count
The demolition itself was only one part of the operation.
Over the course of the closures, the team needed to temporarily remove around 160 metres of permanent vehicle restraint system from the central reservation, move approximately 700 metres of temporary vehicle restraint system, remove around 450 tonnes of concrete and steel from the two gantries, and then reinstate the temporary and permanent restraint systems, including new concrete footings for the permanent system.
Using the 4D approach allowed the team to understand the relationship between these activities and test the proposed sequence before committing people and plant to it, as well as disrupting the motorway network.
The result was a carefully rehearsed operation designed to make the best possible use of the available closure window, in which the project team was able to complete the closure of the motorway in 25 hours in weekend one – eight hours ahead of the planned closure of 33 hours. The second weekend closure was delivered six hours ahead of schedule.
A model for predictable, best-in-class delivery
The demolition at Simister Island demonstrates how digital construction planning can move beyond visualisation and become an active part of delivery.
By bringing programme, construction information and the physical environment together in 4D, teams can rehearse complex activities before they happen, identify risks and opportunities earlier, and create a common understanding of work. All of this allows our teams to make our physical, best in class delivery more predictable.
“This is a great example of the power of 4D construction sequences to help support our focus on predictable, best-in-class delivery. Through meticulous planning and the use of cutting-edge technologies we were able to deliver this work safely and to schedule, while ensuring the M60 carriageway and surrounding highway infrastructure remained fully protected.”
Tom Rogers Digital Delivery Lead