The Texas Department of Transportation (TXDOT) is investing in the northern extents of the Dallas/Fort Worth Metroplex with the undertaking of an ambitious $84 million construction improvement to State Highway 121, between the Dallas North Tollway and Ohio Road in Collin County.
The region has seen explosive growth over the past 10 years and is in need of added traffic capacity. Similar to many other roads in the area, Highway 121 started as a modest country road, and current construction will relieve rush-hour traffic congestion associated with new development in the area.
The project has been divided into several phases, with work currently under way for the second.
Balfour Beatty Construction Inc. is serving as the general contractor and has an array of TXDOT-certified subcontractors in place to complete work on the large roadway project (see Highway 121: Subs on the Job page 2).
The typical cross-section of proposed pavement is designed for ultra-heavy vehicular frequency. Thirteen in. (33 cm) of heavy-duty concrete pavement will be placed on top of a 4-in. (10.2 cm) base, which sits on 31 in. (78.8 cm) of lime-treated subgrade. Such a large quantity of lime requires placement and compaction in a series of lifts, each roughly 6 in. (15.2 cm) in depth.
The heavy-duty pavement thickness accompanies a wide right-of-way, whose main lanes feature three through-lanes in each direction separated by a 26-ft. (7.9 m) median, a 10-ft. (3 m) shoulder on each side, and a bar-ditch to handle surface runoff during rain events.
To ease traffic control and management of the project, the highway department has phased the job to include large-scale construction of service roads along the outer extents of the right-of-way for Highway 121. This enables a surrounding infrastructure to channel traffic along the lanes that will ultimately be dedicated for use as service lanes, while the main lanes are built during subsequent phases of construction.
So that traffic control sequencing can work smoothly, the project also involves substantial realignment of existing intersections and creek crossings, most notably the upper extents of the White Rock Creek Watershed, and streets such as Hillcrest, State Highway 289 (known to Dallasites as “Preston Road”), McDermott Street, and, at the terminus of the project, Ohio Road. These improvements range in scope from obliteration of old pavement on the ancillary roadways that connect to Highway 121 to complete realignment and resignalization of arterial intersection crossings that handle thousands of cars per day.
Balfour has earned accolades for the quality of work and adhering to the fast-paced schedule of operations.
“The entire paving operation was exemplary and the finished quality of the concrete paving was outstanding,” said James Hunt, TXDOT’s director of construction, of Balfour’s recently completed first phase. “I would like to express our gratitude for Balfour Beatty’s proactive position on improving ride quality and the overall quality of the pavement being placed.”
The status of the project can be tracked on the highway department’s Web site: www.dot.state.tx.us.
David H. Recht owns an Irving, Texas, based civil engineering and construction firm. His e-mail address is firstname.lastname@example.org. CEG