A continuously sinking site, very soft clay containing more water than solids, corrosive ground water, strong seismic shaking, a volcano and a never attempted before funicular roof. These are some of the challenges faced when designing the foundation of the New Mexico City International Airport (NAICM).
The foundation of the main terminal structures of NAICM is a single compensated raft over 1.6Km long, 600m wide and 500,000m2 of plan area. The single jointless foundation supports over 25 distinct structures, ranging from elevated highway bridges, car parks, a train station and the terminal superstructures and the distinctive terminal roof. This campus foundation sits on Texcoco lakebed, an area of renowned soft lacustrine clays undergoing continuous regional subsidence.
The project has required a unified and intimate understanding of the geotechnical science, analytical structural engineering and practical construction innovation. The presentation discusses, from both the structural foundation engineer’s perspective and the geotechnical engineers’ perspective, the practical solutions derived to manage the multiple challenges and of course foundation settlement management during and after construction. Construction methods are discussed to illustrate how the means of construction influenced the final solutions, as how the specific demands of the jointless funicular roof shaped the foundation works. These challenges are all considered in the context of a critical airport facility to be built on a fast schedule.
Finally, performance of the as-built raft is discussed and compared against predictions, including tolerances, settlements during construction and practical considerations of the follow-on superstructure construction.