Automation has improved the precision capabilities of manufacturing large-scale machines. In order to achieve these increasingly tighter tolerances, however, the foundations supporting manufacturing operations must abide by serviceability criteria that seem excessively restrictive in comparison to objectives traditionally established for the design of most structures. Stringent limits on deformations and rotations of massive foundation plinths appear ridiculous relative to normal magnitudes of variability in the properties of foundation soils and concrete. Yet such limits are critical, because minute movements of the base translate into larger movements of the tooling equipment. Stiff soils and mass concrete offer the means to achieve a foundation block that is virtually motionless, but the design takes on tremendous risk. In large-scale construction projects, removal of defective materials or stiffening of the foundation plinth after initial construction is impractical. This paper presents the design and construction of a successfully completed mass concrete foundation that supports a giant moving gantry, while keeping deformations and rotations below the gantry producer's specified imperceptible limits. Actual deformation and rotation results from load tests are compared to the design predictions made by finite element analysis of concrete-soil interaction. In addition, actual temperature data of the concrete during curing and cylinder strengths are used to evaluate the project specifications for mass concrete and refine assumptions of material stiffness. Practical recommendations for design, specification, and detailing mass concrete machine foundations are based on these comparisons of design results, actual test data, and proven construction techniques.
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