Colorado Springs Metro Interstate expansion

The Colorado Springs Metro Interstate Expansion (COSMIX) project, completed in December 2007, was the largest transport improvement project in Colorado Springs’ history. Building Information Modelling was a key tool in helping to deliver the ahead of schedule and on budget.

Interstate as it was in 2005
Interstate as it was in 2005

The project

Map of the project
Map of the project

First opened in 1960, I-25 carried around 8,000 vehicles per day. At the time of project commencement, this had risen to over 100,000.

The comprehensive $150-million design-build project included:

  • One major split diamond interchange including 12 bridge structures
  • Widening of 12 miles of I-25 to six lanes
  • Reconstruction of 16 bridges including interchanges with the Union Pacific Railroad
  • A wetlands mitigation programme with routine monitoring of an environmentally sensitive waterway

This all needed to take place whilst allowing the continuous use by 100,000 vehicles per day. Ultimately the project was completed one year ahead of planned Colorado Department of Transport (CDOT) schedule.

The design-build approach

CH2M HILL was the majority owner of the joint venture responsible for the design-build approach. This approach allowed work to begin on construction before 100 percent design completion. Taking this approach provided a number of benefits. For example, when the design-build team found cost-saving ways to reduce life-cycle costs while enhancing the project. The design shortened the storm drain system to reduce construction impacts to the historic 1930's Work Progress Administration (WPA) wall and floodplain habitat at the Monument Valley Park.

Key to success was the way that the project was divided into four construction segments to allow concurrent design and construction of multiple elements. This was achieved by:

  • An aggressive design and construction schedule that required early construction
  • Starting critical construction elements in segments 2 and 3 while design was ongoing
  • Splitting the four project segments into 14 design packages to optimize phasing
  • Designing, fabricating, and delivering long-lead materials to the project site on time
  • Conducting phased reviews of plans to allow early construction in each segment

Performing proposal-phase aerial photography and pre-award project mapping that provided a head start to our 18-month design phase.

Quality, safety and public information planning were integrated into these processes to ensure a comprehensive programme management approach. A collaborative team comprising 180 staff from the joint venture and 45 staff from CDOT helped to ensure project successful project delivery.

he successful approach was founded on design-build Building Information Modelling (BIM) based on Bentley software solutions. These were used to deliver the:

  • Preliminary design for the initial proposals
  • Design deliverables driven by the construction schedule
  • 'Living' plan documents

The software was able to integrate the efforts from multiple, and dispersed, designers providing relevant and timely electronic deliverables against a fast paced schedule.

The BIM technology (InRoads) was used to:

  • Convert 7 different survey data areas, CAD/design data based on multiple software systems and 3 different centre line station bases into one complete project coordinate base and InRoads files
  • The use of Light Detection and Ranging (LIDAR) high-definition survey techniques to create 3D models of existing structures and topography which are integrated into the overall BIM model
  • Present preliminary designs, including alternative configuration concepts and the ability to quickly visualise and assess design alternatives, to CDOT
  • Develop project standard InRoads standards, file structuring and appropriate guidelines
  • Integrate the efforts of multiple designers
  • Align the design schedule with the construction schedule and provide access to the current status of plans for all members of the team through Bentley's Digital I Plot and Digital Archive
  • Provide direct coordination of design data with field survey and construction crews ensuring accuracy and consistency as well as integrating the Quality Control systems with the BIM. Deliverables included 3D models which provided direct GPS control of plant and grading equipment

The ability to deliver to requirement, on target for cost and one year early was based on:

  • Time invested in initial planning and setup
  • Having a single BIM system to manage CAD setup and configuration, and underpin the entire design and build process
  • Frequent sanity check reviews of the design process using the BIM model of the 'living design'
  • A fully integrated team of designers, constructors, BIM support team and client

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