have been developed for evaluation of effective soil elastic moduli and stiffness of
structures. New concepts are proposed for determining some soil input parameters for
design in expansive soils such as the depth of the active zone for heave and edge moisture
variation distance. Several case history studies of ribbed and flat mat foundations
have been investigated to assist determination of suitable procedures for calculating
deformati-n behavior of mat foundations.
Analysis of the performance of a large ribbed mat foundation supporting building 333,
Red River Army Depot, proves the viability of selected instrumentation and methodology.
The observed earth pressure distribution shows extremely large concentrations of soil
pressure near the perimeter indicating rigid behavior on an elastic soil or soil shear
at the perimeter. The extended distribution of earth pressures from column loads
indicates the effectiveness of stiffening beams in spreading applied loads. Evidence
is presented indicating that concrete shrinkage and foundation distortions during
construction may sometimes let stiffening beams of ribbed mats hang in the trenches
without soil support, which may contribute to mat fractures when superstructure loads are
applied. Observed strains in the concrete mat were generally consistent with observed
deformation patterns.

A preliminary systematic damage record system was developed to catalog most
frequent damages, assist identification of causes of damage from foundation movements,
and assist determination of requirements for maintenance and repair of military facilities.
Recommendations are made for field surveys of detailed surface soil and foundation
movement patterns and other work to investigate a new frequency spectrum approach
and ground modification methods to improve understanding and performance of military
facilities, improve design of foundations, and reduce maintenance and repair requirements

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