Load Redistribution in Frame with Settling Footings

Abstract

A computer program is presented that can be used to estimate actual final settlements for any frame supported on isolated spread footings. These footings can be founded in any type of soil stratum consisting of any combination of sand layers, normally consolidated or overconsolidated clay layers. Settlements are computed based on one‐dimensional consolidation theory for normally consolidated and overconsolidated clays and on Schmertmann's technique for sand layers. Influence of load redistribution from surrounding footings due to frame action is incorporated directly into the settlement computations. Application of program methodology to three rigid frames indicates that forces induced by differential settlement can be significant, leading in some cases to stress reversal, when compared to the situation where the footings are assumed not to settle. On the other hand, rules of thumb traditionally used to limit differential settlement in a structure of the type investigated were found to be overly conservative.