Bearing capacity of a strip footing placed next to anexisting footing on frictional soil

Christoph Schüdderich*, Arash Alimardani Lavasan, Franz Tschuchnigg, Torsten Wichtmann

*Corresponding author for this work

Research output: Contribution to journalArticle


The ultimate bearing capacity of a single/isolated footing has been investigated intensively by many researchers. Although a lot ofstudies considered different aspects affecting the bearing capacity, only very few focused on the influence of an existing footing on thebearing capacity of a new footing in its close proximity. In this study, the influence of an existing footing on the ultimate bearing capacityof a recently constructed footing in a close spacing has been investigated with respect to different sizes of the footings, spacings betweenthe footings, friction angles of the subsoil and loads applied on the existing footing. Numerical simulations based on finite-element limitanalysis (FELA) are utilized to determine lower and upper bounds of the ultimate bearing capacity which bracket the exact solution frombelow and above. The results for isolated footings are compared with selected data from literature in terms of the bearing capacity factorNcindicating good agreement of both, lower and upper bound values. Accuracy of the results was enhanced by applying an adaptivemesh refinement technique which enabled a more precise approximation of the failure mechanism and a better estimation of the exactsolution due to smaller differences between the lower and upper bound solutions. The results for footings placed next to an existing foot-ing are discussed with regard to the interference factorncas well as the shape and size (extend) of the failure mechanism. The resultsillustrate that two types of failure mechanisms may develop which either extend up to the front edge of the existing footing or pass under-neath. Comparisons with previous studies revealed that interference factors have been improved significantly due to utilization of adap-tive mesh refinement technique. Moreover, design charts for an estimation ofncare presented for variable footing width ratios, spacingsbetween the footings, friction angles of the subsoil and loading factors of the existing footing.
Original languageEnglish
Pages (from-to)229-239
Number of pages11
JournalSoils and foundations
Publication statusPublished - 1 Apr 2020

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