Performance-based designs for footings placed on reinforced ground that take their ductile behaviour into account require better knowledge of the settlement of footings subjected to peak footing loads. The validity of theoretical formulae for ultimate bearing capacity and settlement for footings on reinforced level ground, proposed previously by the author, are examined, based on recent experimental evidence. It was found that the formula for the ultimate bearing capacity increase in reinforced level sandy ground, based on the deep-footing and wide-slab mechanisms proposed by the author, works well in evaluating ultimate bearing capacity ratios for footings placed on level ground reinforced with high-tensile-stiffness reinforcement. The upper and lower bounds for footing settlements under peak footing loads were derived based on 42 loading test results. They were then applied to three additional series of loading tests using various types of reinforcing material, such as a relatively extensible polymeric mesh and three-dimensional geocell layers with a deep embedment. There was good agreement between the theoretical and measured values of ultimate footing settlement ratios for reinforced ground reinforced with a high-tensilestiffness geogrid. It was indicated that using three-dimensional geocell reinforcement with a deep embedment may generate greater footing settlements than those predicted by the upper-bound equation proposed here. It was also indicated that using high-tensile-stiffness geogrids in reinforced compacted dense sand tends to generate slightly lower values of ultimate footing settlement ratio, SRf, than those predicted using the lower-bound equation proposed here. Settlement characteristics of compacted sands, in contrast to the pluviated sands conventionally used for deriving experimental databases, may account for this discrepancy; this requires more study in the future.
All Science Journal Classification (ASJC) codes
- Geotechnical Engineering and Engineering Geology