Considered to be the number one economic engine for the Dallas/Fort Worth metroplex, the Dallas/Fort Worth International Airport (DFW) covers more than 29.8 sq. mi. and is located in the cities of Euless, Grapevine, Irving and Coppell, TX.
It is the second largest airport in the United States and the third largest in the world in terms of operations, housing five terminals, 165 aircraft boarding gates and seven runways with one more being planned.
An airport of this magnitude and production requires constant maintenance on runways, terminals and gates to keep operations running smoothly and safely.
In September 2005, DFW International awarded a $21.3 million airport taxiway reconstruction project to general contractor Granite Construction Co. The project involves the reconstruction of the existing Taxiway K, the main taxiway for all airplanes to maneuver to their assigned gates. Taxiway K is 8,500 ft. (2,591 m) long and requires work to be completed in 10 sections and seven phases.
The details of the reconstruction process include removing existing concrete and asphalt pavement, unclassified excavation, repavement, drainage, pavement markings and electrical work.
Granite Construction contacted Caprock Specialty Contractors of Dallas to help with the removal of the concrete pavement. Caprock has, for the last five years, specialized in flat sawing, core drilling, wall sawing as well as grinding and grooving in the Dallas and Houston areas.
For this job, it was decided that flat sawing was the best alternative to cut the perimeter of the area.
The contractor would then use guillotine stompers on the interior area of the taxiway.
Caprock Specialty Contractors felt that flat sawing was a better alternative to cut through the 1.25 in. dowels found at the joints.
In addition, flat sawing would provide a better way to prevent any damage from vibration to the communication and guidance system of the airport while maintaining a tight work schedule.
The first cut on the perimeter was made with a saw that had a 20- by .25-in. (51 by .64 cm) blade; thereafter, they increased blade sizes in steps, ranging in size from 36- by .25 in. (91 by .64 cm); 48- by .22 in. (122 by .56 cm); 54- by .187-in. (137 by .47 cm); to 60- by .187-in. (152 by .47 cm) to 72- by .22 in. (183 by (.56 cm).
At this stage of the sawing, they had to adapt a 48- by .0375 in. (122 by .095 cm) quarry blade to widen the cut before using a 90- by .375-in. (229 by .95 cm) blade to cut the remaining 9 in. (23 cm) of concrete to achieve the required depth of 41 in. (104 cm).
The next step in the sawing process was to locate the 90-in. (229 cm) blade to finish the cutting.
K2 Diamond, of Torrance, CA, located a 90-in. blade core in the United States and added the necessary segments to the blade to make the final cut. Diamond Equipment Services helped out with the next step, which was to attach a Caterpillar skid steer 262B to the blade so workers could pick the 700 lb. (318 kg) blade up out of the cut and move it to the next area.
The attachment of the blade to the skid steer was the main safety concern that Caprock faced with this job.
It planned an arbor with an 8-in. (20 cm) hub and a six bolt pattern to hold the blade on to prevent failure. It also integrated a bypass on the hydraulic system to prevent damage to the blade or the machine in the event that the blade locked up.
It also fabricated a blade guard that was reinforced at the leading edge to contain the blade in the event it became detached while operating.
So far, Caprock is pleased with the performance of the equipment. In fact, Brad Boyd, general manager for Caprock, said that the modified piece of equipment has “saved us a tremendous amount of time associated with making a cut this deep and the ability to move the blade without detaching it has proved to be one of the key reasons we have been able to maintain the cutting schedule.”
The process of removing and replacing the Taxiway K at DFW International Airport is an ongoing job for Caprock Specialty Contractors, with an expected completion date of January 2007.
When this job is completed, Caprock will have cut a total of 1,900 linear ft. of reinforced concrete, at a depth of 41 in. and it will have cut and sealed 100,000 sq. yds. (76,455 sq m) of green concrete.
(This article originally appeared in June 2006 issue of Concrete Openings magazine.) CEG