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146Aggregate Piers – Bearing capacityObtained bearing capacity values were found to have a trend to increase in a non-linearfashion with the increasing number of piers within the group (Table 31). Single pier wasfound to bear 1.1 MPa - 1.9 MPa, while the group of 6 had a load capacity of 8.4 MPa – 15.5MPa. For most of the obtained results short piers were found to have similar bearing capacityas long piers within the same pier group, where only group of six was found to be an outlier.When performing comparative analysis between the lab and field bearing capacity results, itwas found that the values were to closely correlate. However, no particular trend wasnoticed. Figure 82 shows comparison between single piers, groups of four and groups of fiveaggregate piers. Full-scale piers are not necessarily of the same length as the lab 305 mm and610 mm piers and, therefore, additional field replicating testing would be required to identifythe field and lab correlation.Aggregate Piers - Group EfficiencyGroup efficiency calculations were performed at 2 mm, 5 mm and 10 mm top of the pierdisplacements. The group efficiency results with respect to single pier were summarized inTable 27 and with respect to unit cell were summarized in Table 28. Some of the majorconclusions were made based on the pier length, number of piers within the group andmagnitude of settlement at service and ultimate load conditions.Having the piers built at short 305 mm and long 610 mm lengths, the findings have shownthat the group efficiency with respect to single pier was consistently greater in magnitude forshort piers than for the long ones. In some cases the difference between short and long pierswas exceeded by a factor of two leading to a conclusion that some of the shorter groups ofaggregate piers were twice as efficient as the groups of piers of greater length.