The Crawlerway at the Kennedy Space Center is a 130-foot wide and over 4.2-mile long pathway between the Vehicle Assembly Building (VAB) and the two launch pads at Launch Complex 39. Natural soil and 3 feet of hydraulically dredged soil are below a 5-foot layer of compacted limerock, which lies beneath a 4 to 8 inch surface of Alabama river rocks, which were chosen for many properties, including hardness, roundness, sphericity and resistance to LA Abrasion. The Crawlerway was constructed in the early 1960’s and supported heavy space rockets being rolled to the launch pads throughout the Apollo and Shuttle Programs. Since the end of the Shuttle Program, heavy loads have not been traversing along the Crawlerway for many years and the Crawlerway soil foundation strength has waned and needs refurbishing and strengthening to support NASA’s next space program. By 2013, a project to repair and upgrade the Crawlerway was undertaken. It was the first time the foundation had been repaired since it was constructed. The limerock layer was increased by 2 inches, and the degraded river rock was removed and replaced with new river rock.
The Crawlerway was originally designed to support the weight of the Saturn V rocket and its payload, plus the Launch Umbilical Tower and Mobile Launch Platform (MLP), atop a Crawler Transporter (CT) during the Apollo Program. The total load to the ground was over 17 million pounds. The Crawlerway was also used from 1981 to 2011 to transport the Space Shuttles, also atop the MLP and CT, with a total load of 18 million pounds.
Jones Edmunds provided a study to evaluate the Crawlerway foundation for the transition from the Shuttle Program to NASA’s new heavy-lift vehicle, SLS. The Shuttle weighed 18 million pounds, and NASA’s new heavy-lift vehicle is expected to weigh over 26 million pounds.
The goals of this project included determining if the foundation could handle the increased load and performing a full-scale load test using a CT shoe to find the most suitable surface to use with the new heavy-lift vehicle.
We coordinated with several NASA organizations and their subconsultants to mobilize the load test apparatus, including Ames Research Center, Florida Department of Transportation, USACE ERDC, United Space Alliance, and EG&G. The load test required 500,000 pounds of weight vertically loaded onto the existing CT track shoe. A 250-ton “water bottle”, which NASA uses at the VAB to certify cranes, was used as ballast for the horizontal load. The load test included evaluating various gravel materials and resilient mats, while pressure cells were used to better understand distribution of the load under the CT shoe.
This project was awarded the 2011 Florida Section Project of the Year by the American Society of Civil Engineers.