Repairing “Dale’s Dips” at Texas Motor Speedway
Texas Motor Speedway
Fort Worth, Texas
The modern race car being driven on the professional circuit today is an aerodynamic wonder. With mere inches of ground clearance, the car is designed to utilize airflow over the body of the car to force the tires down firmly against the pavement, maximizing traction. The objective, of course, is to safely maximize speed.
In the fall of 2006, Dale Earnhardt, Jr., and other Nextel Cup drivers criticized Texas Motor Speedway regarding “bumps” in the 1.5-mile track between turns one and two. They said that these bumps limited them from running “multiple grooves” on the track (the “side-by-side” racing that NASCAR fans crave) and made it difficult to control cars coming out of turn one.
Texas Motor Speedway responded to this criticism immediately, engaging surveyors to shoot elevations across the track to detect any track deficiencies. It was determined that the unlevel areas were not “bumps”; to the contrary, the problem was, in fact, areas of settlement, dubbed “Daleʼs Dips” by the press.
Understanding the design of the track structure helps to understand the nature of the problem. The banked turns of the 60-foot wide Texas Motor Speedway sit at a 23-degree angle; therefore, there is a considerable amount of fill material under the upper portions of the track.
In these turns, the construction design includes 4 inches of asphalt laid over 12 inches of concrete, which sits atop an approximately 9- inch thick concrete “drainage mat.” Because this is a heavy structure, it is imperative that the fill materials supporting the track be properly compacted.
Further complicating the construction of the track are large access tunnels under each turn that provide infield access to the NASCAR racing teams and fans. Due to inadequate compaction of the fill materials around these tunnels, the track had settled slightly on both sides of the tunnel.
The degree of settlement was so slight that it would not have been detected if it had occurred on a city street, but given the aerodynamics of a race car, it was an issue to some NASCAR drivers.
URETEK ICR was selected to make the track repairs for several reasons.
- It was absolutely imperative that the track be lifted accurately; an “overlift” in any area would have severely negative consequences for track officials.
- The ideal solution must add longevity and sustain rigorous track use for the future.
- The repair process needed to be completed in a timely manner, as the Speedway hosts training and special event racing almost every week of the year.
- The repairs could not compromise the racing surface, which is meticulously maintained to optimize traction.
The repair process required URETEK to drill 5/8-inch holes in the track into which copper tubes were driven in order to precisely inject URETEKʼs proprietary formulation of structural grade geo-polymer at the proper depth. The rapid expansion of the material allowed for precise, incremental lifting of the track.
The URETEK team worked in conjunction with a team of surveyors, constantly monitoring the lifting process and measuring results within hundredths of an inch. All four corners of the track were alleviated of the troublesome dips.
The entire lifting process was completed within three days and received high praise from Dale, Jr., and other NASCAR drivers.
Since the project’s completion in 2007, there has been no settlement of the track reported and Texas Motor Speedway remains one of the best tracks in NASCAR.