Lateral impact loading and snap-back testing to estimate linear and nonlinear dynamic response of near-shore piles

This paper presents some results of dynamic lateral loading tests on a near-shore steel pipe pile vibrodriven into soft marine clay. Two typologies of tests are carried out on a free head pile: impact load tests and free vibration tests at different load levels. The aim of this experimentation is to investigate the dynamic soil-water-pile interaction and determine the dynamic characteristics of the whole system by means of the two different typologies of test and for different levels of the dynamic input. The obtained results show the complex dynamic behaviour of the vibrating soil-water-pile system in terms of natural frequencies and damping ratios. The values obtained from the two test typologies are compared and the variations with the level of the input force, due to the nonlinear behaviour of the system, are discussed.