Quantifying the impact of stiffness distributions on the dynamic behaviour of railway transition zones

Railway transition zones (RTZs) are regions where abrupt track stiffness changes occur that may lead to dynamic amplifications and subsequent track deterioration. The design challenges for these zones arise due to variations in material properties in both the depth (trackbed layers composed of different materials) and longitudinal directions of...

A new numerical modelling framework for fixed oscillating water column wave energy conversion device combining BEM and CFD methods: Validation with experiments

The Oscillating Water Column (OWC) wave energy converter has been shown to have high potential, thus rendering extensive development in recent years. In order to further accelerate its development, highly accurate yet computationally efficient tools are necessary particularly when studying the interaction of multiple OWC devices. This paper...

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...

Gentle Driving of Piles (GDP) at a sandy site combining axial and torsional vibrations: Part II - cyclic/dynamic lateral loading tests

Gentle Driving of Piles (GDP) is a new technology for the vibratory installation of tubular (mono)piles. Its founding principle is that both efficient installation and low noise emission can be achieved by applying to the pile a combination of axial and torsional vibrations. Preliminary development and demonstration of the proposed technology...

Gentle Driving of Piles (GDP) at a sandy site combining axial and torsional vibrations: Part I - installation tests

Gentle Driving of Piles (GDP) is a new technology for the vibratory installation of tubular (mono)piles. Its founding principle is that both efficient installation and low noise emission can be achieved by applying to the pile a combination of axial and torsional vibrations. Preliminary development and demonstration of the proposed technology...

Energy flux analysis for quantification of vibratory pile driving efficiency

In this paper, the energy flux in a pile modeled as an elastic shell, is studied theoretically and experimentally. Based on this analysis, a new procedure is proposed to quantify the pile installation efficiency. This procedure is of importance for vibratory installation of the foundations of offshore wind turbines and it is believed to be...

Dynamic Response Of Two Interacting Extensible Barsin Frictional Contact

In this paper, a new model is developed to describe the nonlinear dynamics of twoaxially deformable bars sliding relative to each other in which the interaction is governed byfriction. The first bar is fixed at one end and is subjected to a distributed normal force perpen-dicular to its axis to activate friction at the common interface, while...

Observation and interpretation of closely spaced fundamental modes of a high-rise building

In this paper the dynamic behaviour of a high-rise building with complex structural system is studied. In some cases, to optimize the building design, the horizontal stability of the building is accomplished by the contribution of several structural components. This is the case of the JuBi tower, the building studied in this paper. The...

Frequency effects in the dynamic lateral stiffness of monopiles in sand: insight from field tests and 3D FE modelling

With the offshore wind industry rapidly expanding worldwide, geotechnical research is being devoted to foundation optimisation - most intensively for large-diameter monopiles. The analysis and design of monopiles still suffers from significant uncertainties in relation to cyclic/dynamic loading conditions. The aim of this work is to shed new...

Vibration-assisted installation and decommissioning of a slip-joint

The structural failure of grouted connections for offshore wind turbines focused the industrial attention towards different and innovative solutions to guarantee a safe connection between the monopile foundation and the turbine tower. An alternative option to the traditional grouted joint is a direct steel-to-steel connection, also called a...

Dynamic soil stiffness for foundation piles: Capturing 3D continuum effects in an effective, non-local 1D model

A method is presented to accurately capture the 3D interaction phenomena of a foundation pile embedded in soil, in a computationally efficient non-local 1D model. It is shown how to extract the global stiffness kernels from simulations with the 3D inhomogeneous continuum, and implement them in a 1D non-local Winkler-type model that can...

Semi-analytical solution for the dynamic response of a cylindrical structure embedded in a homogeneous half-space

This paper addresses the dynamic response of an infinitely long cylindrical structure embedded in an elastic half-space. The structure has a circular cross-section and its axis is parallel to the half-space surface. Excitation can be incident body waves or forces applied on the surface of the half-space and/or the structure. The model can be...

Wave reflection at the interface between a nonlinear discrete lattice and a matching linear system

This contribution considers the wave reflection at the interface between a discrete lattice that describes the nonlinear near-field response to a dynamic load and a matching system that describes the linear far-field response. The near-field system is modelled as a one-dimensional discrete system of particles that is capable of describing...

Model Solutions for Performance-Based Seismic Analysis of an Anchored Sheet Pile Quay Wall

Conventional seismic designs of quay walls in ports are mostly based on pseudo-static analysis. A more advanced alternative is the Performance-Based Design (PBD) method, which evaluates permanent deformations and amounts of (repairable) damage under seismic loading. The aim of this study is to investigate the suitability of this method for...

Wave radiation from vibratory and impact pile driving in a layered acousto-elastic medium

A steel monopile is the most common foundation type of a wind turbine installed offshore and is driven into place with the help of vibratory or impact hammers. Underwater noise generated during the installation of steel monopiles has recently received considerable attention from international environmental organizations and regulatory bodies in...

Transition radiation excited by a load moving over the interface of two elastic layers

Transition radiation is emitted when a perturbation source (e.g., electric charge, mechanical load), which does not possess an inherent frequency, moves along a straight line at a constant velocity in or near an inhomogeneous medium. The phenomenon was described for the first time in electromagnetics, but it is universal from the physical point...

Model-based force identification in experimental ice-structure interaction by means of Kalman filtering

The level-ice forces exerted on a scale model of a compliant bottom founded structure are identified from noncollocated strain and acceleration measurements by means of a joint input-state estimation algorithm. The identification is performed based on two different finite element models: one entirely based on the blueprints of the structure, and...

Steady-State Response of Periodically Supported Structures to a Moving Load

Steady-state vibrations of periodically supported structures under a moving load are analytically investigated. The following three structures are considered: an overhead power line for a train, a long suspended bridge and a railway track. The study is based on the application of so-called 'periodicity condition', which implies that the shape of...