The Dallas High Five, the freeway interchange connecting Central Expressway (U.S. 75) with the Lyndon B. Johnson Freeway (I-635) was completed ahead of schedule, to the delight of thousands of daily commuters.
The name “High Five” was introduced by the Texas Department of Transportation (TXDOT) to much fanfare, having involved the public in the naming process, and symbolic of the five interchange ramps that tower in the North Dallas skyline.
Dallasites remember the day when Central Expressway was rebuilt — depressed below grade, widened, and landscaped — 15 years ago. The end product was visually appealing, but the construction process was arduous for all parties involved, including the city, the contractor, and, especially, the motorists of Dallas.
Charles Carr had the unique perspective of driving through both construction zones, Central Expressway in the past decade and the recently completed Dallas High Five.
“I am amazed at how fluid the traffic flow was during construction,” he said. “My route through the High Five was from the south heading onto 635. Initially, I was able to use Coit Road as a conduit but once the overpass was open I was able to choose. Compared to the congestion caused when 75 was undergoing construction in the early 1990s, this was a breeze.”
H.B. Zachry Construction Corporation broke ground on the Dallas High Five in 2002, a construction project worth $260 million. The High Five project was unique in how its construction contract was written.
According to written obligation, Zachry paid “lane rentals,” a fee to TXDOT for closures of live traffic lanes.
Pricing for such closures was assessed on an hourly basis, and the fee was directly related to the traffic volume of the lane that was closed at the time of day that it was closed.
These fees ranged dramatically from $50 per hour all the way to $110,000 per hour for a rush hour closing of an arterial lane or vital connecting ramp.
The payments provided substantial financial incentive for the general contractor, and H.B. Zachry finished the job ahead of schedule.
Beyond the factors of timing and traffic, the project was carried out safely, which was a priority identified from the beginning by all stakeholders.
In order to maintain safety, there was extensive planning toward the logistical aspects of the project.
A 41-acre staging area was located on the southeast corner of the site. In addition to on-site batch concrete mixing, it was on this staging area that Zachry received and distributed the numerous pre-stressed beams, hydraulic structures to support three major creeks flowing underneath the towering piers, miles of reinforcing steel, and assorted construction equipment to build the High Five.
One unique piece of equipment for the project was the segment erector, designed and constructed by Deal S.R.L. of Italy.
The erector weighs 101 tons (92 t) and measures 97 by 38 by 37 ft. (29.6 by 11.6 by 11.3 m) and cost approximately $1 million.
Dallas Morning News illustrations revealed to the public a machine unlike anything else in the industry. Initial piers and bridge segments for elevated sections of the interchange were assembled using traditional on-the-ground cranes.
Once in place, the segment erector was wheel-based and free to move laterally along the concrete beam on which it sat. This allowed for assembly of bridge segments hoisted by the segment erector from the ground.
During heavy lifting, the segment erector would eschew its tires in favor of balancing on hydraulic lifts, to brace the equipment against live loads in excess of 30 tons.
Once assembly from a given pier was complete, the segment erector was disassembled, and placed on another assignment.
Efficient workmanship is supplemented by a vibrant artistic design element. The High Five could double as an immense piece of public art.
Recognized for its colorful etchings on various pieces of pre-cast concrete, and wide use of colorful finishing agents throughout the project extents, the Dallas High Five has gained accolades from government watchdogs as being a visually appealing elevated freeway interchange. Such positive feedback will be used on future public works projects statewide.
TXDOT also utilized the internet to communicate with the traveling public.
A Web site published the day-to-day details of construction phasing and project benchmarks, which, along with traditional television, radio, and newspaper communication through conventional media, provided practical information to the public. The Web site, www.dallashighfive.org, currently shows construction photos, and other project-related data.
In the midst of a busy time, when other major infrastructure projects are ongoing and planned for the city of Dallas and the TXDOT, the related positive publicity to the success of the Dallas High Five is a well-deserved accolade for both government and H.B. Zachry Construction.
(David H. Recht owns an Irving-based civil engineering and construction firm.) CEG
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