Ground motion reduction in vibratory pile driving via axial and torsional vibrations

In this paper, the characteristics of the induced ground motion are studied for two pile installation methods. Specifically, the classical axial vibratory driving is compared with the Gentle Driving of Piles (GDP) method, to investigate the effect of high-frequency torsional excitation in the soil response. For that purpose, a non-linear 3-D...

The mechanics of the Gentle Driving of Piles

Gentle Driving of Piles (GDP) is a new vibratory installation technology for tubular (mono)piles. It is characterized by the simultaneous application of low-frequency axial and high-frequency torsional vibrations, envisaged to achieve both high installation performance and reduced underwater noise emissions. The concept of GDP has been...

A non-linear three-dimensional pile–soil model for vibratory pile installation in layered media

This paper presents a computationally efficient model for vibratory pile installation. A semi-analytical finite element (SAFE) model for thin cylindrical shells is derived to represent the pile. The linear dynamic response of the soil medium is described by means of Green's functions via the Thin-Layer Method (TLM) coupled with Perfectly...

An alternating frequency-time harmonic balance method for fast-slow dynamical systems

The Alternating Frequency-Time (AFT) Harmonic Balance method has been widely applied in the analysis of non-linear mechanical systems under periodic excitation. Customarily, a periodic displacement is considered as ansatz in a harmonic balance analysis. In the present work, a deviation from the latter ansatz is realized and the periodicity is...

Study of the sound escape with the use of an air bubble curtain in offshore pile driving

Underwater noise pollution generated by offshore pile driving has raised serious concerns over the ecological impact on marine life. To comply with the strict governmental regulations on the threshold levels of underwater noise, bubble curtains are usually applied in practice. This paper examines the effectiveness of an air bubble curtain...

Installation of large-diameter monopiles: Introducing wave dispersion and non-local soil reaction

During the last decade the offshore wind industry grew ceaselessly and engineering challenges continuously arose in that area. Installation of foundation piles, known as monopiles, is one of the most critical phases in the construction of offshore wind farms. Prior to installation a drivability study is performed, by means of pile driving...

Monitoring Monopile Penetration Through Magnetic Stray Field Measurements

Current methods to infer the penetration of a steel monopile during an offshore installation are rather inaccurate. Since a large number of foundation piles will be installed offshore in the coming years, a reliable technique to infer the penetration depth is vital. This paper proposes a non-contact method to monitor the pile progression into...

The steady-state response of a rotating ring subjected to a stationary load

The in-plane steady-state response of a rotating ring on elastic foundation subjected to a stationary load is investigated theoretically using a high-order model in the framework of the plane strain assumption. The adopted high-order model accounts for the through-thickness variation of stresses and displacements, as well as the boundary...

Transient laminar flow in hydraulic networks based on a semi-analytical impulse response method

The importance of transient analysis in hydraulic networks has been well recognized due to abrupt changes in flow or pressure introduced by valve closures or component failures. Therefore, accurate and robust numerical models are necessary to analyse the travelling pressure waves as a result of such sudden changes. This paper presents the...

The completeness of the set of modes for various waveguides and its significance for the near-field interaction with vibrating structures

Modal decomposition is often used in geophysics and acoustics for the solution of problems related to wave propagation in elastic or acousto-elastic waveguides. One of the key elements of this method is the solution of an eigenvalue problem for obtaining the roots of the characteristic equation, which may signify either frequencies or...

Transient laminar flow in hydraulic networks based on a semi-analytical impulse response method

The importance of transient analysis in hydraulic networks has been well recognized due to abrupt changes in flow or pressure introduced by valve closures or component failures. Therefore, accurate and robust numerical models are necessary to analyse the travelling pressure waves as a result of such sudden changes. This paper presents the...

Transient laminar flow in hydraulic networks based on a semi-analytical impulse response method

The importance of transient analysis in hydraulic networks has been well recognized due to abrupt changes in flow or pressure introduced by valve closures or component failures. Therefore, accurate and robust numerical models are necessary to analyse the travelling pressure waves as a result of such sudden changes. This paper presents the...