The $238 million ROC 52 design-build project in Rochester was a signature undertaking that broke new ground in the delivery of highway projects in Minnesota. Traffic congestion was already burdensome on the TH 52 corridor, the principal route between Rochester and the Twin Cities of Minneapolis and St. Paul, and every indication was that it would get worse. Forecasts suggested that traffic volume would double by 2029 to more than 100,000 vehicles a day.
Rochester is the center of commerce and agriculture in southeastern Minnesota and, as home to the Mayo Clinic, is host to more than 1.5 million patients each year. TH 52 passes through the heart of Rochester and is adjacent to the clinic.
Seeking to head off further congestion, the Minnesota Department of Transportation (Mn/DOT) started planning a decade ago to widen the 11-mile highway corridor from four to six lanes. As planning for the reconstruction project developed, it became clear that it would require continuous construction of the corridor for more than 11 years. The local business community, concerned that the length of the construction process would have a serious impact on commerce, asked Mn/DOT to perform an economic impact study of the project. Among the study’s conclusions was the recommendation that the construction process be shortened from 11 to five years to minimize disruption to the area.
Designated for Design-Build
In an effort to compress the design and construction schedule, Mn/DOT coordinated with the City of Rochester and Olmsted County and designated the project, ROC 52, as the state’s first large transportation design-build project and the largest public works project in Mn/DOT’s history. It also was identified as a Best-Value project to make certain that the reduced delivery time would not sacrifice the quality of construction. All told, the $232 million signature project included a mainline, widened from four lanes to six; a system of frontage roads to accommodate the wider highway; extensive noise and retaining walls; and 26 bridges, two of which cross the Zumbro River.
The design-build team that would undertake the effort consisted of three design firms — URS Corporation, Yaggy Colby Associates, and Alliant Engineering — and three construction firms — Fluor Corporation, Ames Construction, and Edward Kraemer & Sons. Together, they formed the design-build team of the Zumbro River Constructors (ZRC). ZRC promptly created a partnership with the public agencies of Mn/DOT, the City of Rochester, Olmsted County, and the Federal Highway Administration. The partnership also included a proactive public outreach program that solicited public support for the project.
At its inception, the project was scheduled by Mn/DOT for completion in five years. It celebrated its grand opening nearly two years earlier than originally scheduled. The reduced timeframe was due to innovative engineering as well as to unique design-build management and control techniques during the proposal stage and throughout the duration of the project. These techniques included alternative technical concepts (ATC), visualization, machine control, and sub-surface utility engineering (SUE).
Alternative Technical Concepts
Alternative technical concepts are important innovative tools of design-build. They are design innovations submitted by private sector contractors to the public agency project owner, in this case Mn/DOT, during the proposal process. The ATCs are offered in response to the design that is specified in the owner’s request for proposal. The goal of these innovations is to shorten the project schedule and/or reduce project cost. The ZRC team submitted 30 ATCs, 16 of which were approved by the Mn/DOT. Four were of particular significance:
- An alignment alteration at the key interchange of TH 52 and Civic Center Drive saved nearly one construction year. By slightly revising the alignment, the roadway was kept within the right-of-way but eliminated expensive temporary paving, bridges, and shoring.
- A single-point urban interchange (SPUI) at 19th Street saved the project almost $1 million. The proposal called for a bridge with steel girders which are difficult to build and expensive to maintain. Instead, prestressed-concrete girders were used as a low-cost, high-quality alternative to the steel girders. As added benefits, the prestressed-concrete girders do not require periodic painting, they reduce long-term maintenance costs, and they increase safety by eliminating the need for personnel to be suspended over the busy highway.
- Mechanically stabilized earth (MSE) walls saved the project considerable time and cost. They replaced cast-in-place walls primarily in embankment fill areas between TH 52 and its frontage roads. MSE and soldier pile retaining walls saved construction time and 20 percent of the cost by reducing excavation and shoring and lessening traffic disruption. In addition, MSE walls, which have a 100-year design life, are safer to build because they do not require significant excavation and the corresponding wide backslopes
- A wooden deck on a temporary bridge near the Mayo Clinic, which replaced a concrete deck in the Mn/DOT proposal, sped up the project and was reused after the project was completed. ZRC determined that the concrete deck would shift and crack after repeated use, causing a safety hazard to cars traveling below it. The wooden deck could also be put in place quicker because it could be fabricated on the ground and lifted into place with a small crane. For added measure, since the wooden deck surface was similar to pedestrian bridges elsewhere in Rochester, it could be used as a permanent bridge when ROC 52 was completed.
One other innovation, after construction started, was sparked by the same innovative thinking process in design-build that was shown in ATCs. During the first year of the project, a decision was made to dramatically change the construction staging, by starting in the rock cut area, at the south end of the project, This entailed at significant change in the staging plan and the excavation and removal of 300,000 cubic yards of rock and 40,000 cubic yards of overburden in less than 14 weeks. To effect these changes, the ZRC team worked in a spirit of partnership with its public agency partners to revise the staging design and to reduce the amount of rock cut and speed up its removal. This required extensive blasting and hauling which were costly and raised safety concerns. An alignment and grade change lessened the rock cut excavation. A change in traffic staging for the duration of the rock cut, from two continuous lanes to one in each direction, sped up excavation. By working together as partners, ZRC and Mn/DOT kept the project on schedule and made the construction area safer for both the contractor and the traveling public.
Visualization
The ROC 52 project introduced the Minnesota design community to the concept of visualization, which was used in two ways. First, a before-and-after fly-through was created to show Mn/DOT how moving the key bridge at the TH 52 and Civic Center Drive interchange saved the project significant construction time. That visualization was shown at several public meetings and on the project web site.
The second use of visualization was on the 19th Avenue SPUI bridge. To alleviate concern over whether the bridge would ease congestion at the intersection, URS created a visualization that showed actual traffic flowing through the interchange, assuring both Mn/DOT and the City of Rochester that the design would be effective.
Machine Control and Sub-surface Utility Engineering
Machine control, which is the guidance of construction equipment using GPS based upon engineering design files, was tested and implemented on ROC 52 for both rough and final grading. It eliminated a significant amount of field survey time and cut several months from the time of construction. Machine control was not part of the initial ROC 52 proposal. It was implemented, after construction started, by a cooperative effort of the ZRC project team and the Mn/DOT.
Because of the “lessons learned” from utility conflict issues on the project, Mn/DOT decided to institute the use of SUE on all future design-build and most large public works projects. Future SUE surveys will precisely locate underground utilities in x, y, and z coordinates.
Management Tools
In addition to technical innovations, a number of management initiatives also helped to expedite the project. Foremost among these were co-housing and the use of work management teams (WMT). Co-housing, the sharing of office space by the owner, Mn/DOT, and the ZRC team, was cited as the “single most important factor in the success of the project.” The shared office space facilitated over-the-shoulder design review and lent added importance to the comprehensive quality control/quality assurance program. By locating the entire team in one building near the project site for the duration of construction, communication was improved and construction issues were often resolved before they became problems.
The work management team approach entailed: dedicating qualified personnel for each function for as long as they were needed; structuring the project team as a matrix for effective communication among all team members; partnering with Mn/DOT; promoting a culture of safety for the protection of the traveling public and for workers; educating the team about environmental compliance and integrating those concepts into work activities; and providing a public outreach program to disseminate information and receive input from the public. The open channel of project communication was practiced, informally, every day within the co-housed office and, formally, every week in regular WMT meetings when the team met to identify and resolve project issues.
Safety Program
Safety was a principal consideration throughout the course of the project. In addition to the incorporation of safety improvements into the design of the MSE walls, the wooden pedestrian bridge, and the rock cut area, safety was a factor in the maintenance of traffic (MOT) plan, the use of ZRC courtesy safety vans, and the interchange at 75th Street. The MOT plan required two moving lanes of traffic in each direction during the entire project, and every effort was made to minimize traffic crossovers and detours wherever possible.
The realignment of TH 52 and Civic Center Drive eliminated almost a year of traffic detouring, and emphasis was placed on improving safety by eliminating mainline traffic detours during the winter season, which in Minnesota extends from November through March. In addition, the project made use of Intelligent Transportation Systems (ITS). Through the use of ITS video equipment and changeable message signs, traffic flow and incidents were monitored constantly in the project corridor and coordinated with Mn/DOT and the state patrol.
Environmental Issues
Like all large transportation projects, ROC 52 faced a host of environmental issues. ZRC created an environmental compliance team with knowledge of and a working relationship with all regulatory agencies, expediting permit application and review. Specific environmental issues included wetland permitting, construction material runoff, and noise control.
Although wetland definition and permitting were completed prior to the design-build award, the ZRC team created an independent audit of wetland compliance during construction. Every wetland adjacent to the project area was monitored to see if it was properly fenced and to make sure that no construction material runoff was entering the wetland during construction.
Noise control on a project is critical in maintaining positive relations with the adjacent community. Noise walls were built early in the project to mitigate noise during construction and to minimize traffic noise after completion of the project. The impact of noise on each residence along the corridor was monitored and measured against standard cost effectiveness criteria to determine whether a noise wall was required.
Aesthetic Considerations
Aesthetics are given a high priority on all public works projects in Minnesota. An aesthetic design guide was created by a citizens group during the planning stage and implemented during design and construction. Artists’ renderings and animations were shown to the citizens group throughout the design stage and during construction. The nature of the materials, the colors, and the shape of each structure were all part of the aesthetic process.
Overall, the innovative design-build process accelerated completion of the project from an initial estimate of 11 years to three years and kept the final cost of the project within the original estimate. In addition to the enormous saving in time, the project minimized traffic congestion, eased disruption to the neighboring community, and resulted in several hundred million dollars of economic benefits to the community.
A final test of the project’s success was in the public’s eye. At the project’s grand opening the local newspaper editorialized, “The performance of everyone working on ROC 52 has been miraculous. What they have completed in three years has earned the thanks of Rochester.”
INFO: URS (www.urscorp.com)