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This paper presents the results of field tests performed to investigate the field behaviour of winged-monopile foundations. The principle of the winged monopile is that steel plates are attached to a standard monopile (in the area near the ground or seabed surface) to increase the foundation stiffness and lateral resistance. The experimental tests described in this paper consisted of load tested driven instrumented prototype scale standard (reference) monopiles and piles with varying wing geometries at two sand sites. The overall load–displacement performance and mobilised bending moment profiles were examined to assess the potential benefits of adding wings to monopiles. Experimental p–y curves were developed for the piles to analyse how the presence of wings influenced the soil–structure interaction of the foundation system. The use of simplified p–y methods for predicting the winged-pile response was assessed. The experiments proved that the addition of wings greatly improved the lateral resistance and stiffness of the piles; however, the results suggest that conventional p–y curve methods are limited as they cannot account for the effect that the enhanced stresses mobilised by the wings have on the strength and stiffness response of the pile below the wing location.

This paper presents the results of full-scale load tests performed to investigate the end bearing pressure mobilised by continuous flight auger piles installed in sand. In particular, the tests considered the effects of the footing width and, by varying the load test procedure (from maintained load test to constant rate of penetration), allowed quantification of creep effects. By comparing the load test results with in situ test results from cone penetration tests, correlations between the end bearing pressure mobilised at normalised settlement levels of 10% of the footing width and the cone penetration test qc value were studied. For the maintained load tests, these correlations were found to be similar to those used in routine design practice. When creep effects were reduced using constant rate of penetration load testing, the end bearing pressure mobilised was significantly higher than that assumed in normal practice, and it was in keeping with the results of finite-element analyses performed using a soil model that ignored creep. In the final section, the field test results are compared to database pile load tests performed on non-displacement piles in sand.

This paper describes the results of static compression and tension load tests performed on three-instrumented large diameter Continuous Flight Auger piles installed in Dublin boulder clay. The piles developed very high shaft resistance and, in contrast to piles driven into boulder clay which exhibit friction fatigue, the shaft distribution was uniform along the pile shaft. This resulted in the normalised average shear resistance being mobilised by a bored pile exceeding that of a pile driven in similar ground conditions. In contrast the base resistance of the test piles were significantly lower than a pile driven in similar ground conditions. Not applicable UCD Urban Institute Ireland ti,ab,sp.kpw25/8/10