Suggested Analysis and Design Procedures for Combined Footings and Mats ACI 336.2R-88

Description

This report addresses the design of shallow foundations carrying more than a single column or wall load. Although the report focuses on the structural aspects of the design, soil mechanics considerations are vital and the designer should include the soil-structure interaction phenomenon in connection with the design of combined footings and mats. The report excludes slabs-on-grade.

Soil contact pressures acting on a combined footing or ma tand the internal stresses produced by them should bedetermined from one of the load combinations given in Section 1.3.2, whichever produces the maximum value forthe element under investigation. Critical maximum momentand shear may not necessarily occur with the largestsimultaneously applied load at each column.

The maximum un factored design contact pressures shouldnot exceed the allowable soil pressure, qa. The value of qashould be determined by a geotechnical engineer.Where wind or earthquake forces form a part of the loadcombination, the allowable soil pressure may be increased asallowed by the local code and in consultation with thegeotechnical engineer.