As part of the airport improvement program at Dallas Fort Worth International Airport (DFW), a new airfield concrete ramp was designed and constructed to increase gate capacity to serve wide- and narrow-body aircraft. The ramp is approximately 1,450 feet long by 690 feet wide constructed on a partially developed area that included access and service roads, a partial taxiway entrance, and several staging areas. Aircraft movement simulations were conducted to establish the optimum aircraft parking layout and separation between taxiways, taxilanes, vehicle service roads, and hardstand parking positions. The field investigation for pavement design revealed existing soils consisted of lean clays near saturation with low amounts of sulfates. The soil investigation concluded lime stabilization was a feasible alternative for the construction of the cement treated base and the concrete pavement. During the initial construction stages, verification sulfate tests indicated adverse sulfates contents to those obtained during design. The findings jeopardized the lime stabilization approach and a potentially substantial change order would be required if a subgrade replacement approach was conducted. After additional tests conducted by the contractor's quality control and the airport's quality assurance laboratories, it was concluded that most of the existing soils were adequate for lime stabilization and that only a few localized areas had elevated amounts of sulfate. A modified lime stabilization approach was conducted to address any potential issues with lime stabilization of elevated sulfate contents in soils. Construction of the base and concrete pavement were successful, and no major issues were encountered. This project was carefully phased to allow construction of the ramp to be predominately outside of the airport operations area (AOA) and completely removed from movement areas by installing temporary AOA fencing. This allowed the contractor to finish in 18 months; four (4) months ahead of schedule. This paper will present the planning, design, and construction considerations conducted for the successful completion of this project.
展开▼
