The M25 motorway that circles London is already one of Europe’s busiest highways, with some sections handling almost 200,000 vehicles a day. When London hosts the 2012 Summer Olympic Games, organizers expect the influx of an additional 1 million visitors. Although the M25 is not part of the official Olympic Route Network, it is likely to be used by many people traveling to the games.
To relieve the motorway’s day-to-day congestion levels, improve journey times and safety, and increase traffic capacity, England’s Highways Agency awarded a £6.2 billion design, build, finance, and operate (DBFO) contract to the Connect Plus consortium in 2009 for future development, operation, and maintenance of the M25. Part of this contract includes widening over 23 miles of the motorway’s northwestern quadrant and 17 miles in the northeast from 3 lanes to 4.
The Highways Agency is responsible for operating, maintaining, and improving the strategic road network in England. The Connect Plus consortium comprises Atkins, Skanska, Balfour Beatty, and Egis Road Operation U.K. Atkins is the U.K.’s largest engineering and design consultancy and the world’s 11th largest design firm. Skanska is one of the world’s largest project development and construction groups, with expertise in construction, development of commercial and residential projects, and public-private partnerships. Balfour Beatty is a world-class infrastructure services business operating across the infrastructure lifecycle.
This effort is also constrained by the boundaries of the current road. “In addition to adding two lanes, the design incorporates a new central reserve barrier, additional gantries, and new roadside lighting,” says Hugh Woods, a senior group engineer at Atkins. “Therefore, all of these features must fit into the existing boundaries of the M25, which requires precise design and construction coordination.” Furthermore, three lanes of traffic in each direction must be allowed to proceed at all times during construction of the new roadway, necessitating careful construction planning.
Atkins designers use Autodesk® Navisworks® Manage software to aggregate their multidiscipline design information, which is developed with thirdparty and AutoCAD® software. The Skanska Balfour Beatty Joint Venture team then uses AutoCAD and AutoCAD® Civil 3D® software to adapt the Navisworks model for construction purposes, adding greater realism and context to the design components. “It’s not about creating pretty pictures,” says Owens. “Autodesk BIM for infrastructure solutions give us a more accurate engineering representation of the highway and a deeper understanding of the project during construction.”
To help meet their aggressive schedule, the project team relies on a more coordinated, accurate design model. Created in Navisworks, the integrated design model helps the team visualize and coordinate the whole project, including all above ground and underground components as well as nonphysical aspects of the design, such as safety and access zones. “Navisworks helps us identify and resolve interdisciplinary clashes, many of which would be very difficult to detect using 2D documentation,” says Woods.
Inform Decision Making
When the design is issued for construction, the project team adapts the Navisworks design model, using AutoCAD Civil 3D to enhance the design intent and create a virtual construction model that incorporates more realistic versions of some of the design elements, such as fences, crash barriers, and retaining walls. The team also adds elements such as point clouds from laser scans, and temporary works. “This construction model makes the project easier to understand for all the on-site staff,” says Woods. “It informs their decisions for construction planning and helps them better understand their options when site conditions necessitate changes.”
Stay on Schedule
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