Dynamic response of laterally loaded piles in clay

The behaviour of single piles under lateral dynamic loading is critical, and has been an important field of research since the 1950s. Many analytical or semi-analytical linear and non-linear models are available to estimate the dynamic lateral stiffness, but it is essential to determine the dynamic characteristics of the soil-pile system through full-scale lateral dynamic pile load tests for important structures and for validation of existing models. This paper presents the results of field lateral dynamic load tests conducted on 33 piles of varying types-driven precast concrete, driven cast-in-situ concrete and bored cast-in-situ concrete-at different petrochemical complexes in India. The results indicate that driven precast concrete piles have stiffnesses that are four to five times higher than those of driven cast in situ piles. The lateral stiffness was also estimated using the computer program PILAY for all piles and compared with the stiffness determined from the field tests. The estimated stiffness shows good agreement with the field values for stiff clay sites, but greatly overestimates the values for soft clay sites.