Settlement Limitations of Foundation

Settlement limitation requirements in most cases control the pressure which can be applied to the soil by the footing. Acceptable limits for total downward settlement or heave are often 1 to 2 inches or less.

(1) Total Settlement. Total settlement should be limited to avoid damage with connections in structures to outside utilities, to maintain adequate drainage and serviceability, and to maintain adequate freeboard of embankments. A typical allowable settlement for structures is 1 inch.

Tie Beam or Grade Beam Cracks Associated with foundation Settlement

(2) Differential Settlement. Differential settlement nearly always occurs with total settlement and must be limited to avoid cracking and other damage in structures. A typical allowable differential/span length ratio D/L for steel and concrete frame structures is 1/500 where D is the differential movement within span length L.