This case study discusses how four overflow abatement storage facilities with a combined storage volume of 21.25 million gallons and two additional storage facilities with a combined storage volume of 12 million gallons to provide peak flow equalization were successfully constructed on an accelerated schedule using CM-at-Risk project delivery as opposed to a more traditional design/bid/build approach.By Craig Parker and Dwayne Frye
With sewer overflows and aging wastewater system infrastructure growing concerns across the U.S., , the Knoxville Utilities Board (KUB) is under a federal Consent Decree to make system improvements. KUB accelerated its wastewater improvement efforts by launching Partners Acting for a Cleaner Environment (PACE 10) in October 2004.
PACE 10 includes a mix of ongoing maintenance programs, replacement and rehabilitation to increase conveyance capacity, upgrades to optimize plant operations, and wet-weather storage facilities. KUB chose to include storage to more quickly and surely meet regulatory deadlines to eliminate sewer overflows and to help relieve stress on treatment plants during heavy rains.
To help bring storage online more rapidly, KUB elected to seek an alternative to the traditional design/bid/build method of project delivery. It decided to engage a qualified construction manager (CM) to deliver four storage projects with a total volume of 21.25 million gallons via the CM-at-risk method. With that method, the construction manager agrees to deliver the project within a specified timeframe and under a negotiated Guaranteed Maximum Price (GMP). KUB based its decision on numerous factors, including schedule, quality, economy, and change management, and staff carefully considered each factor during selection of the CM firm.
The CM-at-risk method won out for two primary reasons:
- The shorter projected schedule for overall project delivery – with CM-at-risk, the CM can accelerate procuring major equipment and start construction before having a completed design and before obtaining all permits and approvals. Though an early start can be risky, its potential benefits outweighed the KUB team's concerns.
- The advantage of construction quality and innovation – CM-at-risk offers qualifications-based selection, constructability/Value Engineering reviews at each phase of design, and provisions for shared savings.
All in all, CM-at-risk supported a faster delivery schedule, more quality oversight, and greater flexibility. It also limited the risk of cost and schedule growth, contractual entities, points of responsibility, claims for additional cost, and construction headaches.
Following a qualifications-based construction manager selection process, KUB chose Brasfield & Gorrie, LLC of Birmingham, Alabama to deliver the four storage facilities via CM-at-risk, where the construction manager self-performs all work for which it is qualified. The CM self-performed work included excavation, reinforced concrete, process piping, equipment installation, and building construction. The four projects were designed, constructed, and commissioned in 30 months at a total construction cost of approximately $47 million.