This text describes the design and performance of a shallow spread footing foundation system for a large medical care facility in Mexico City. The project is unusual because the spread footings bear on a combination of basaltic lava and coarse sand fill containing angular lava fragments, the latter of which was densified using the dynamic deep compaction process. In the following narrative, the exploratory program is described, the geotechnical design and construction process is explained, and the inspection procedure for footings bearing on rock and soil is discussed. Further, the results of precise settlement monitoring for the structure are presented
