Transit agencies are increasingly pursuing alternatives to traditional low-bid procurement to build projects rapidly and more cost-effectively. One non-traditional procurement that is emerging as a trend in the transit industry is Construction Manager/General Contractor (CM/GC). Although this procurement method has been used in vertical construction projects for many years, it is still not as common in the transit industry and is starting to gain traction.
The CM/GC process is divided into two phases, a pre-construction phase and a construction phase. The project owner hires the general contractor during the design phase – usually between the 30-60 percent design stage – before the start of construction. This is the pre-construction phase. During this phase, the contractor provides preconstruction services including sub-surface utility engineering, estimating, budgeting, scheduling, value engineering and other design and construction input. Then, the general contractor provides a Guaranteed Maximum Price (GMP) and may be retained to construct the project. Typically, the CM/GC performs part of the work and bids discrete portions of the work to sub-contractors.
In recent years, projects such as Seattle Sound Transit’s East Link, Denton County Transportation Authority’s (DCTA) A-Train, sections of Dallas Area Rapid Transit (DART) light rail and Portland’s Tri-Met have used this delivery method. Los Angeles County Metropolitan Transportation Authority (L.A. Metro) is currently in the process of selecting a CM/GC contractor for its $2.3-billion Link Union Station project (LINK US).
Unlike other non-traditional procurement methods, such as design-build and public-private partnerships where the design and construction services are retained under a single contract, in a CM/GC, the project owner retains the designer and the general contractor under separate contracts.
The CM/GC process is a middle-ground method that offers several advantages, including:
- Maintaining Design Control: Unlike a design-build project where the contractor oversees the designer, the project owner has direct control over the design. Most transit agencies have certain standards and legacy systems where major innovations/changes to these standards are not possible, therefore the design-build delivery may not be practical. However, with CM/GC, the owner can maintain those standards, yet obtain a degree of innovation utilizing the contractor’s input as appropriate.
For example, the LINK US project will transform how the regional rail system operates in southern California by converting the Los Angeles Union Station from a stub-end station to a run-through station by extending tracks south over the US 101 freeway. One benefit of utilizing CM/GC on this project is taking advantage of the contractor’s ideas for staging. Constructing this project while maintaining rail operations is key. Taking advantage of the contractor’s input early on in how to construct while maintaining service is important. Knowing how the contractor would like to stage the work provides the agency with a more cost-effective design for the staging, minimizing disruptions to the traveling public and vital passenger rail operations. This staging benefit also translates to the viaduct over US 101. This is a major artery moving Angelenos and Californians through the city. Engaging the contractor along with the California Department of Transportation to review and understand the impacts of constructing a bridge over this highway with minimal impacts is essential to the project’s success.
- Saving Costs/Time: CM/GC allows the designer and general contractor to collaborate early in the project process, thereby saving time and money. For instance, the DCTA’s A-Train, which was built using the CM/GC delivery method, experienced cost overruns at the beginning of the project. To bring the construction costs down, the CM/GC team, with the program manager and designer, conducted a weeklong value engineering workshop and came up with several solutions, including reusing a historic bridge; building a relief bridge to prevent flooding; applying drainage solutions such as constructing earth ditches and reusing existing culverts; specifying foundation changes; and implementing material changes at station platforms. The various solutions generated more than $32 million in cost savings and the project was ultimately built on budget.
In addition to costs, the CM/GC method can allow transit agencies to build projects faster. In 2013, DART extended the Blue Line south for three miles to the University of North Texas at Dallas. The project, known as the South Oak Cliff Blue Line Extension, was originally scheduled to be completed in 2019. Using CM/GC, DART accelerated the schedule by three years for a 2016 completion.
- Encouraging Innovation: The collaborative process encourages the designer to learn from the contractor and explore alternative designs, including innovative techniques or approaches. For instance, part of the DCTA rail corridor crossed a 175-foot truss bridge that was built in 1910 over the Trinity River near Lewisville. Prior to the A-Train project, the existing traffic on the structure consisted of local freight trains that operated at 30 mph at a minimal frequency of two or three times a week. Implementing the A-Train project meant that the historic bridge would need to carry local freight trains, as well as Budd RDC and Stadler GTW vehicles operating at speeds of up to 60 miles per hour, at a combined frequency of almost 30 trains a day.
Initially, the design team planned a parallel bridge for the A-Train project. After evaluating the available traffic information, the material properties of the bridge and the loading effects of the different vehicles, the contractor recommended reinforcing the existing bridge instead of building a parallel bridge. The design team then determined that the existing bridge, once reinforced, could sustain the loading and frequency of the various vehicles, eliminating the need for an expensive solution.
- Reducing Change Orders: One of the major advantages of CM/GC projects is that the contractor is involved during the design development. This helps reduce errors and omissions, thereby minimizing change orders during construction and resulting in cost overruns. Changes are minimized by the contractor supporting design, providing needed utility investigation and working early with owner and designer on construction methods. Many times, changes are caused by unforeseen conditions, usually due to a utility not known during design. With the contractor’s support through potholing and other physical methods of discovery, these unforeseen changes are minimized.
- Minimizing Risks: With the contractor involved early in the process, CM/GC allows an equitable sharing of project risk between the owner and the contractor. As the design progresses, the contractor gives input and provides cost estimates. At the same time, the contractor also continues to advise and update the construction schedule. Furthermore, the contractor performs sub-surface utility engineering, which minimizes utility conflict risks. By the time construction begins, the project owner has more certainty about the project costs and final schedule.
Currently, DART is modifying 28 of its existing platforms (constructed prior to 2004) to allow operational flexibility by accommodating three-car light-rail trains. These modifications will provide additional capacity during peak commute times. The project includes extending and raising portions of the platforms to allow for level boarding. These improvements are being delivered through a CM/GC contract. DART chose this method to obtain the contractor’s input into staging and to maintain light-rail service throughout the expansion. The contractor’s input can help maintain service, limit disruptions and maintain a reasonable schedule for the completion of the project.
While CM/GC has several advantages, it is not a panacea for all transit projects. For example, CM/GC is not needed to build a new line section in a corridor already owned by a transit agency. Projects that are best suited for the CM/GC process typically feature one or more of these issues: complex components that require innovation, multiple stakeholders, located in urban areas, high public expectations or include right-of-way or utility issues that impact the overall schedule.
Before embarking on a CM/GC process, transit agencies must do their due diligence, including research, talking to other agencies/entities, determining the specific CM/GC expertise available in the agency or hiring a consultant with CM/GC expertise. Once the transit agency decides to go ahead with CM/GC, it is critical that the general contractor is retained early in the design phase. If these steps are followed, the transit agency will be able to fully reap the benefits of the CM/GC method.
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Timothy Schmidt is a senior associate and California transit director for Lockwood, Andrews & Newmnam, Inc. (LAN), a national planning, engineering and program management firm. He has served as a CM/GC consultant for several transit projects including DCTA’s A-train and DART’s Phase II Build-Out. He has also managed design-build transit projects, including DART’s Owners Representative for the Blue Line Extensions to Rowlett, and as the design manager for the VTA/BART Berryessa Extension.
