In August 2016, construction commenced on improvements to the State Highway 121/360 interchange in northeastern Tarrant County, the third most-populous county in Texas. This $61 million undertaking is the first of several Texas Clear Lanes projects aimed at reducing gridlock and improving mobility around the state's most congested areas. When complete, the new interchange will minimize weaving and cut down on traffic delays on both SH 121 and SH 360.
"As someone who drives these roads almost every day, I know how critical this interchange is to mobility in our Metroplex"¦Projects like this one will go a long way toward reducing congestion in our region," says Texas State Senator Jane Nelson (R-District 12).
These upgrades are part of the DFW Connector project, a massive 14.4-mile infrastructure overhaul in the Dallas-Fort Worth (DFW) Metroplex that is being spearheaded by the Texas Department of Transportation (TxDOT). In 2009, TxDOT entered into a comprehensive development agreement on this project with NorthGate Constructors as general contractor. NorthGate Constructors is a joint venture led by Fort Worth-based Kiewit Texas Construction LP, and San Antonio-based Zachry Construction Corp.
"One of the most rewarding aspects of the project is the outstanding teamwork between NorthGate Constructors and TxDOT. Over the last decade, this team has built a strong relationship to provide a safe and high-quality highway system for North Texas commuters," says Acting TxDOT Fort Worth District Engineer Loyl Bussell, PE.
Booming Population Escalates Urban Congestion
Reconstruction of the SH 121/360 interchange is intended to reduce traffic bottlenecks and improve safety in the burgeoning retail and industrial Grapevine area. The city's population - reported at just under 50,000 in 2014 - is projected to exceed 53,000 by 2019. This represents an 8 percent increase in just five years. The Grapevine community is also affected by DFW's population growth, which is forecasted to reach 16.3 million by 2050 - a 130 percent jump from 2015 population stats at 7.1 million. Recent data released by the U.S. Census Bureau reveals that Texas' populace increases by about 1,200 each day - the largest population upturn of any state in the country.
According to a 2016 report published by the American Road & Transportation Builders Association (ARTBA), highway traffic delays in urban areas have increased 500 percent over the past two decades, costing an estimated $6.7 billion annually (an average $570 per commuter). In 2011, the Texas Transportation Commission's 2030 Committee released an analysis on how urban congestion is compounded by transportation investments that fail to keep pace with population and job growth. The study predicts that, by 2035, state congestion levels could tack on around 130 extra hours to a motorist's annual commute time - a shocking 250 percent upsurge compared to delays averaging 37 hours in 2011.
A Closer Look at the DFW Connector
Construction on the DFW Connector began in early 2010. At $1.1 billion, it was the largest design-build project awarded by TxDOT at the time. Funding included $261 million received from the American Recovery and Reinvestment Act of 2009 (the largest amount received by any highway project in the country), as well as allocations from public gas taxes and Proposition 14 bonds.
The DFW Connector consisted of 8.4 miles of roadway, including four highways, two interchanges, five overpasses, 37 bridges, new direct connect ramps and continuous frontage roads. In the widest section of the project, highway capacity was expanded from 12 to 24 lanes. Crews also added 4 miles of TEXpress Lanes on SH 114 to aid in congestion management. By the end of 2018, eight major DFW corridors will feature TEXpress Lanes and HOV/Express Lanes spanning more than 120 miles.
Other mobility enhancements consisted of upgrades to highway, bridge, drainage and intelligent transportation systems. Noteworthy project quantities included 1.6 million square feet of concrete paving, 130,000 linear feet of drainage installation, 2.9 million cubic yards of excavation, 2.1 million cubic yards of embankment and 725,000 square feet of mechanically-stabilized earth wall installation. Completion occurred nine months ahead of schedule in August 2013 and essentially doubled the existing highway system capacity around the north entrance of the DFW International Airport, which globally ranks third in operations and tenth in terms of passengers serviced.
The initial project scope included reconstructing the SH 121/SH 360 interchange. However, capital was not available for this project element until February 2016. Funding was made possible thanks to TxDOT's Texas Clear Lanes initiative, a program that prioritizes voter-approved funding for congestion relief projects in Texas' major metropolitan areas. An initial $1.3 billion was allocated to Texas Clear Lanes to provide mobility solutions in the Austin, Dallas, Fort Worth, Houston and San Antonio areas. Major benefits include more reliable travel times, improved mobility and safety, enhanced operational efficiency, and lower fuel consumption.
New Direct Connectors Ease Mobility
Two major weaving movements are the root of congestion issues around the SH 121/360 juncture. This is primarily caused by the design of the main lanes, which ferry motorists directly through the city of Grapevine. To ease access and smooth traffic flow, four new direct-connecting ramps are being built along a 1.6-mile stretch of roadway between SH 114, SH 121 and SH 360.
Two new ramps are in the works at northbound SH 360 - one to northbound SH 121 and the other to westbound SH 114. A new ramp at northbound SH 121 will transition traffic to westbound SH 114. Crews will construct a ramp from eastbound SH 114 to southbound SH 121, and reconfigure the existing ramp from eastbound SH 114 to southbound SH 360. From southbound SH 121, a new ramp will connect to SH 360. NorthGate Constructors will also reconfigure the northbound SH 121 exit to the William D. Tate Avenue exit.
During the next several months, construction activities will involve setting girders on top of bridge columns and continuing bridge deck placement on three of the flyovers. Work will begin on new drainage systems in the center median of northbound and southbound SH 121, and on a concrete box culvert system in between northbound SH 121 and the adjacent existing frontage road. Grading crews will start excavation, embankment and lime activities on the new northbound SH 360 to the westbound SH 114 alignment. Crews are performing work mainly at night to minimize the impact of construction activities on local businesses and travel times. Substantial completion is estimated to be reached by late 2018.
Complementing upgrades to the SH 121/360 interchange are new ramps from southbound William D. Tate Avenue to SH 121 and SH 360, which opened to the public in November 2015.
A Tactical Model of Operational Efficiency
Since this project is design-build, various strategies are being implemented to increase efficiency. To optimize phasing sequences and maximize productivity, project officials strategically identified detour locations that would open up larger areas of work space. Furthermore, NorthGate Constructors has provided TxDOT with multiple value engineering options while still adding capacity to the corridor. "In one instance, we updated the design for the new southbound SH 121 exit to SH 360 by removing a curve, which made the new exit safer for the traveling public. The new design also eliminated material quantities," says Public Information Manager Alyssa Tenorio, NorthGate Constructors.
Prior to construction, the general contractor identified several potential utility conflicts that would ultimately affect the new design. By working with TxDOT to adjust the roadway profile to avoid relocating utilities, the team ultimately reduced overall project costs and improved scheduling. A case in point is the northbound SH 121 frontage road, where four fiber-optic lines cross the right-of-way within a few hundred feet.
"The initial roadway profile required a cut in this location. It was determined that raising the profile 2 to 4 feet would give us adequate clearance for the utilities to remain in place," says Tenorio. The design team also resolved vertical clearance and geometric constraints in the new profile proposal.
The operations team is utilizing SmartSheet for scheduling, document control and daily coordination between crews. This cloud-computing platform manages and automates collaborative work in real time. "The online form system allows for seamless daily checklist uploads and minimizes double-handling and lost information," says Tenorio. The software can be integrated with other popular business systems and applications, such as Salesforce, Microsoft Office 365, JIRA and G Suite.
NorthGate Constructors is also using an integrated material-tracking system called FiveCubits to electronically integrate buyers with suppliers and haulers. "This web-based tool streamlines the distribution of bulk materials, and provides a GPS fleet-management system for real-time truck management," explains Tenorio.
For grading operations, a GPS machine control system is being used to cut down on survey resources and increase equipment efficiency. In addition, team members are utilizing a wireless paving system to enhance accuracy and create a safer work environment.
The Bigger Picture
Rebuilding his portion of the original DFW Connector does not simply advance safety and alleviate gridlock challenges in Grapevine. This focused initiative also represents a unified objective to expedite infrastructure enhancements by accelerating project delivery.
And as it continues to maintain 80,000 miles of roadways across the state, a now 100-year-old TxDOT is continuing its mission to connect Texans to the people and places they love.
"As the severity of congestion in the Lone Star State continues to grow, we are committed to delivering projects many Texans need and deserve to reduce the amount of time they spend in traffic," says TxDOT Executive Director James Bass.
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