TxDOT Tackles $143M Project in Dallas

Tue February 19, 2008 - West Edition
David H. Recht



Texas Department of Transportation (TxDOT) is in the midst of a $143 million infrastructure overhaul in Arlington, Texas, the crossroads of the Dallas/Fort Worth Metroplex.

Originally bisected by the old Dallas Turnpike (now I-30), the city of Arlington is the host to major tourist destinations such as the Six Flags Theme Park, Major League Baseball’s Texas Rangers, and, as of the 2010 National Football League Season, the Dallas Cowboys.

Work on the on-system improvement to Interstate 30 (I-30) in Arlington started in fall 2007.

TxDOT tabbed Zachry Construction Corporation, a general contractor located in San Antonio, Texas, to lead the project. The company was chosen because it had extensive experience building heavy highway projects for the state.

TxDOT has made an incentive-laden deal with Zachry Construction if the project is completed by fall 2010.

The construction contract will end 40 months after letting, January 2011, in time for Super Bowl XLV in Arlington.

In addition to the general contractor, TxDOT employed subcontractors, including striping crews, demolition trucks, traffic signal installers and utility contractors. The subcontractors also have financial incentives for early completion.

The I-30 region has had substantial increases in traffic volume since the original construction of the turnpike in the 1950s. The road has been maintained and upgraded throughout the past half-century but the basic geometry and lane configurations were outdated, according to TxDOT officials.

For instance, ingress to the freeway contains 270-degree “windmill” ramps, which originally were used to stack vehicles leading up to manned toll plazas.

TxDOT funded the on-system improvement to I-30 in Arlington, with the help of local government funding to support the alignment of local north/south arterial cross streets to I-30.

The project will serve increasing traffic volumes, particularly with the arrival of the Dallas Cowboys to Arlington in fall 2009.

The I-30 project extends from Cooper Street to State Highway 360 (SH 360).

In order to establish the new bridges without disrupting service to existing traffic, the contractor saw-cuts the existing bridge decks, shifting traffic onto the remaining half of each individual bridge.

To safeguard the flow of traffic, Zachry Construction will erect high profile concrete traffic barricades (CTBs). Wayfaring signage and temporary pavement markings are placed to facilitate adjustment to motorists’ traffic patterns.

Zachry Construction will mill and stripe IH 30 by using equipment ranging from a riding grinder for large-scale heavy highway re-striping.

However, for tighter working areas such as a bridge deck with a four-lane undivided street section, a walk behind grinder will be used. Those bridges handle traffic during construction. TxDOT will do this by striping the bridge deck on one lane each way during the first phase of bridge erection.

The EBS 125 walk-behind grinder, which had a 5-in. (12.7 cm) diamond grinding wheel and a 14-ampere motor will be used. The walk behind grinder will mill down several hundred linear feet of striping within an hours’ time.

Additionally, Zachry Construction will use slip-form paving machines for heavy highway paving, cranes for erection of pre-stressed bridge beams, beam trucks to transport pre-stressed beams and other equipment associated with heavy highway and civil construction.

Zachry Construction will build the substructure for the IH 30 using reinforcing steel for the drilled shaft. The drill rig will establish the shaft, in accordance with field investigation taken during the design phase of the project by a geotechnical engineer. The rig will drill until it hits bedrock, using previously taken sample borings to estimate subsurface conditions.

During drilling, TxDOT has to account for the possibility of groundwater seepage for extra-depth shafts, which often fluctuate based on seasonal weather conditions. As the shaft goes further down, workers will have to resort to ingenuity to inspect the bottom of the shaft to make sure the auger is drilling evenly. For this, the crews will use mirrors to reflect the light of the sun into the shaft for illumination.

As the Dallas/Fort Worth region continues to grow and expand economically, more and more demands are placed upon existing transportation infrastructure. CEG