Home » Online Exclusives » The Path of Least Resistance

The Path of Least Resistance

By Tom Donaldson

Commuters now can avoid surface streets when traveling highway to highway

New direct connector bridges allow cars to bypass surface streets when traveling from highway to highway, reducing the travel time for commuters driving through the project.

Like electrical current, motorists in large urban centers are continually seeking the path of least resistance. With the completion of the DFW Connector Project, NorthGate Constructors, a joint venture between Kiewit Texas Construction and Zachry Construction Corporation, both members of AGC of Texas Highway, Heavy, Utilities and Industrial Branch, has provided commuters in Grapevine, Texas with just such a path.

In a partnership with the Texas Department of Transportation (TxDOT), NorthGate broke ground on the DFW Connector Project in February 2010. The group was tasked to develop, design and construct the initial 8.4 miles of the ultimate 14.4-mile project to improve mobility and air quality for more than 250,000 daily commuters through the corridor in Grapevine and surrounding communities. The project scope included 14 new main lanes and four toll-managed lanes, as well as frontage roads and direct-connect access ramps to replace the former surface street connections that had contributed to congestion and restriction of traffic flow in the area. Also included were 39 new bridge structures, six bridge class culverts, and extensive drainage lines, retaining walls and earthwork.

A project of this magnitude comes with many unique aspects that required extensive planning and organized project management to overcome. Limited funding, tight project schedule, public communication and outreach, and management of more than 300 separate design packages were some of the challenges NorthGate faced, the solutions for which required innovative construction techniques and creative, outside-the-box thinking.

First and foremost, NorthGate addressed the lack of funding problem. With less than $1 billion available for a project estimated at $1.5 billion, the team needed ways to do more with less. An award of more than $260 million in American Recovery and Reinvestment Act (ARRA) funding helped bridge this gap. NorthGate then sat down with TxDOT to define a revised scope of work to maximize the use of the additional funding.

Once construction began, NorthGate identified its next obstacle: how to keep such an immense, high-profile project within budget and on schedule. “We dissected the $1 billion mega-project into sub-segments called ‘blocks,’ or smaller, more manageable projects that could be closely monitored and measured,” says Kristen Stieg, public information manager for NorthGate. “Using this management method,” she continues, “the team was able to reach substantial completion approximately six months ahead of schedule.”

Another major challenge was determining how to keep traffic flowing while maintaining business access in this busy and growing north Texas region during construction. Solving this problem required careful planning at the project outset, including phasing and sequence of construction, utility negotiations and right-of-way acquisitions, and early construction start-up activities for an accelerated launch. NorthGate also incorporated measures such as installation of detour pavement in strategic areas to allow for longer traffic configuration durations as well as larger work areas, enhancing traffic flow in the work zones while minimizing risks to the workers and the travelling public.

Realizing that a huge effort would be required to disseminate information to commuters and manage impacts to the public during construction, NorthGate created a public information (PI) team to organize and carry out all communication and public outreach efforts. The PI team was comprised primarily of NorthGate employees, with some support from subcontractors (to help with initial project branding, creation of a mobile application, etc.). “NorthGate’s PI team members worked closely with TxDOT public information officers from the Strategic Projects Division and Fort Worth District,” says Stieg. “Together, the group planned special events and communicated construction information to project customer groups, businesses, media and commuters.”

Initially, most people received project information through e-mail alerts and the DFW Connector website. Results of a public survey, however, revealed that these methods alone were inadequate. The PI team, therefore, decided to create a mobile app to provide users with the same information available on the project website, but accessible using their mobile devices. The app, available to both iPhone and Android users, provided the public with the most up-to-date information on construction activities including detour maps, visuals depicting lane closures and traffic switches, and more.

Crews set girders on bridge

Crews set girders on the northbound SH 121 to westbound SH 114 direct connector bridge, which opened in spring 2013.

NorthGate made several state-of-the-art advancements on the DFW Connector project, contributing to the project’s success. One such advancement was the use of Intelligent Compaction (IC), which NorthGate employed as a quality/process control method to ensure the achievement of uniform compaction throughout the fill sections. Two types of IC were employed on the project: Initially, the Compaction Meter Value (CMV) method was used; however, due to the depth of investigation and allowable compaction lift thickness, the team decided to switch to Machine Drive Power (MDP). These IC techniques provided an added benefit of no longer requiring an inspector to randomly select areas for testing, saving manhours and increasing project safety.

Another state-of-the-art approach NorthGate employed on the project was the use of telematics, which involved the transmission of fleet information via the Internet. This technology aided fleet management on the project, improving safety and efficiency by monitoring equipment availability to optimize usage. Telematics also provided accurate equipment diagnostics, and by monitoring such aspects as excess vehicle idling NorthGate was able to reduce operating times of vehicles, leading to lower fuel costs, reduced equipment down-time and maintenance costs, and minimizing its carbon footprint.

NorthGate utilized several other innovative construction techniques in the successful completion of the project, including a field mobility system in which foremen were given wireless laptop computers to update project plans and conduct paperwork in the field; 4D modeling to link 3D design with the project construction schedule, allowing the team to see and understand the sequence of construction activities in real time; an Integrated Material Tracking System to electronically integrate a buyer with suppliers and haulers to streamline the distribution of bulk materials; and wireless paving systems utilizing GPS technology to achieve better accuracy and provide a safer work environment for the paving crews.

Along with careful planning, effective communication and innovative construction techniques, NorthGate’s performance on the DFW Connector project stood out due to its sensitivity to the environment and surroundings. NorthGate implemented several programs that have now become the standard for future TxDOT projects, including employing an on-site concrete batch plant and concrete crusher, and recycling of old rebar. The batch plant and crusher reduced fuel emissions and trucking costs by having the material on-site, and the rebar was recycled by a Texas-based plant for reuse on the new highway system. NorthGate also realized environmental benefits by using an on-site equipment maintenance facility, leading to fewer spills and leaks, lowered air emissions for the area, and increased fuel efficiency. This facility led to the naming of the construction site as the first in the world to reach “World Class” status by the Corporate Caterpillar Assessment Team.

As an example of its awareness of the wildlife in the area, NorthGate changed construction designs to protect riparian habitats and preserve six acres of local wetlands. In addition, prior to all bridge demolitions and tree clearings crews inspected for active bird nests. Several dozen nests were identified and protected until the birds safely departed. And in addition to improving traffic flow for local commuters, the project provided a beautiful landscape and entryway to the local communities with the planting of over 50,000 native plants and wildflowers, including the beloved Texas state flower, the Bluebonnet. All told, NorthGate recycled over 1 million tons of material, had a 95 percent recycling rate, and completed the project without a single environmental violation.

With more than 1,000 employees and 100 subcontractors, the DFW Connector was more than just a big construction project; it put many Texans to work, helping to provide for their families. This, in addition to the innovative techniques employed and extensive environmental mitigation efforts, led AGC of America to award it with a 2014 Alliant Build America Award in the category of Design-Build Highway & Transportation. With all of the new traffic lanes, frontage roads and connector ramps, the circuit is no longer overloaded. Thanks to this new path of least resistance, commuters in Grapevine Texas are spending less time in their cars, and more time with their families