42486
2017
eng
lecture
0
--
--
--
Static and dynamic behaviour of pile foundations in homogeneous and inhomogeneous soils
Offshore wind energy towers are dynamically loaded by waves and wind. Pile foundations provide stiffness and damping and should be properly calculated. A combined finite-element boundary-element method for the dynamic interaction of flexible structures and the soil has been developed. The flexible structures such as single piles or complete wind energy towers are modeled by the finite element method whereas the homogeneous or layered soil is modeled by the boundary element method which uses the Green’s functions for interior loads in the layered half-space to establish the dynamic stiffness matrix of the soil. Soils with a stiffness that is continuously increasing with depth can be modeled as multi-layer soils with step-wise increasing stiffness. The effects of different parameters such as the stiffness of the soil, the axial and bending stiffness of the pile, and the radius of the cylindrical contact area will be analysed for the different components of excitation (vertical, horizontal, rotation and coupling). The results can be determined as specific power laws which are different for the different load cases and for the different soil models (Winkler support, homogeneous continuum, continuum with increasing stiffness). The dynamic effect of radiation damping will be analysed by the frequency-dependent compliance functions. A clear layering of the soil can cause noticeable changes in the dynamic compliances as reductions of the stiffness and the damping in certain frequency ranges (below and around layer resonance frequencies). The distribution of the displacements along the pile help to explain the observed laws. An example of an offshore wind energy tower has been modeled and calculated for wind, wave and weight loads. The resonances of the tower are usually limited by the radiation damping which is strongest for a soft soil.
Compdyn 2017
Rhodes, Greece
15.06.2017
17.06.2017
Lutz Auersch
eng
uncontrolled
Pile foundation
eng
uncontrolled
Finite-element boundary-element method
eng
uncontrolled
Pile bending stiffness
eng
uncontrolled
Soil stiffness
eng
uncontrolled
Continuously inhomogeneous soils
eng
uncontrolled
Layered soils
eng
uncontrolled
Wind energy tower
Angewandte Physik
Ingenieurbau
7 Bauwerkssicherheit
7.2 Ingenieurbau
Energie
Infrastruktur
Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
42089
2017
eng
4675
4690
conferenceobject
NTUA
Athens
0
--
--
--
Static and dynamic behaviour of pile foundations in homogeneous and inhomogeneous soils
Offshore wind energy towers are dynamically loaded by waves and wind. Pile foundations provide stiffness and damping and should be properly calculated. A combined finite-element boundary-element method for the dynamic interaction of flexible structures and the soil has been developed. The flexible structures such as single piles or complete wind energy towers are modeled by the finite element method whereas the homogeneous or layered soil is modeled by the boundary element method which uses the Green’s functions for interior loads in the layered half-space to establish the dynamic stiffness matrix of the soil. Soils with a stiffness that is continuously increasing with depth can be modeled as multi-layer soils with step-wise increasing stiffness. The effects of different parameters such as the stiffness of the soil, the axial and bending stiffness of the pile, and the radius of the cylindrical contact area will be analysed for the different components of excitation (vertical, horizontal, rotation and coupling). The results can be determined as specific power laws which are different for the different load cases and for the different soil models (Winkler support, homogeneous continuum, continuum with increasing stiffness). The dynamic effect of radiation damping will be analysed by the frequency-dependent compliance functions. A clear layering of the soil can cause noticeable changes in the dynamic compliances as reductions of the stiffness and the damping in certain frequency ranges (below and around layer resonance frequencies). The distribution of the displacements along the pile help to explain the observed laws. An example of an offshore wind energy tower has been modeled and calculated for wind, wave and weight loads. The resonances of the tower are usually limited by the radiation damping which is strongest for a soft soil.
Computational Methods in Structural Dynamics and Earthquake Engineering
COMPDYN 2017
Rhodes, Greece
15.06.2017
17.06.2017
Lutz Auersch
Greta Markfort
eng
uncontrolled
Pile foundation
eng
uncontrolled
Finite-element boundary-element method
eng
uncontrolled
Pile bending stiffness
eng
uncontrolled
Soil stiffness
eng
uncontrolled
Continuously inhomogeneous soils
eng
uncontrolled
Layered soils
eng
uncontrolled
Wind energy tower
Angewandte Physik
Ingenieurbau
7 Bauwerkssicherheit
7.2 Ingenieurbau
Energie
Infrastruktur
Verlagsliteratur
Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
47891
2019
eng
228
244
5
120
article
Elsevier
London
1
--
--
--
Compliance and damping of piles for wind tower foundation in nonhomogeneous soils by the finite-element boundary-element method
A combined finite-element boundary-element method for the dynamic interaction of the soil with flexible structures such as single piles or complete wind energy towers has been developed. Flexible piles in different soils are analysed in frequency domain. The different parameters such as the stiffness of the soil, the bending stiffness and the radius of the hollow pile are analysed for their influence on the complex compliances. The results have been determined as specific power laws which are different for the different load cases (horizontal, rocking, coupling) and for the different soil models (Winkler, continuum with constant, root-parabolic and proportional-linear stiffness variation). The strongest influence of the soil stiffness can be found for the homogeneous soil and the horizontal component. Winkler soils have a weaker influence than the corresponding continuous soils. An offshore wind energy tower has been modeled and calculated for wind and wave loads.
Soil Dynamics and Earthquake Engineering
10.1016/j.soildyn.2018.12.005
0267-7261
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=CCC&DestLinkType=FullRecord&KeyUT=CCC:000463130500018
08.05.2019
false
true
Lutz Auersch
eng
uncontrolled
Pile foundation
eng
uncontrolled
Finite-element boundary-element method
eng
uncontrolled
Pile bending stiffness
eng
uncontrolled
Soil stiffness
eng
uncontrolled
Continuously inhomogeneous soils
eng
uncontrolled
Layered soils
eng
uncontrolled
Wind energy tower
Angewandte Physik
7 Bauwerkssicherheit
7.2 Ingenieurbau
Energie
Verlagsliteratur
Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Erneuerbare Energien