1643
Foundation conditions analysis for some eolian power units corresponding to the
seismic loads influence
Analyse des fondations pour certaines unités d’éoliennes sous chargement sismique
Vintila D., Tenea D.
Ovidius University Constanta, Faculty of civil engineering, Constantza, 900524 Romania
Chirica A.
Technical University of Civil Engineering, Faculty of railways, roads and bridges, Bucharest, 020396 Romania
ABSTRACT: The paper presents the main designing consideration corresponding to some romanian location in order to obtain the
most economical foundations. In the eastern part of the Romanian territory (Dobroudgea County) where there are very good wind
intensity conditions the geotechnical studies shows the followings three major lithological types: 1. Rocks layer from the top -
green schists are at the surface of terrain (0 – 4m deep); 2. Rocks layer is situated between 4m deep to 15m and over it is a lossoidal
layer; 3. Rocks layer is deeper then 15m. For each type of soil profile (1,2,3) we have proposed the following foundations: 1. Direct
foundation with two variants, as following: a) direct foundation with skirt embeded in green schist, b) direct foundation laying on an
improved soil, 2. Pile foundation (embedded in green schist), 3. Floating pile foundation. Paper presents some considerations
regarding the influence of seismic loads in foundation design for eolian units.
RÉSUMÉ : L’article présente les aspects principaux afin d'obtenir les fondations les plus économiques dans un site roumain. Dans la
partie orientale du territoire roumain (Dobroudja) où il ya de très bonnes conditions d’intensité du vent, les études géotechniques
montrent trois types lithologiques principaux: 1. Couche de roches depuis le haut - schistes verts à la surface du terrain (0 - 4 m de
profondeur), 2. Couche de roches située entre une profondeur de 4m à 15m et au-dessus couche lossoidale; 3. Couche de roches au-
delà de 15m. Pour chaque type de profil de sol (1,2,3), nous avons proposé les fondations suivantes: 1. Fondation directe avec deux
variantes, comme suit: a) fondation directe avec jupe encastrée dans le schiste vert, b) fondation posée directement sur un sol
amélioré, 2. Fondation sur pieux (intégrés dans le schiste vert), 3. Fondation sur pieux flottants. L’article présente quelques
considérations sur l'influence des charges sismiques dans la conception des fondations pour les unités d’éoliennes.
KEYWORDS: eolian power units foundations, seismic loads.
1 INTRODUCTION.
The paper presents the main designing consideration
corresponding to some romanian location in order to obtain the
most economical foundations for wind farms located in the
Eastern part of Romania (Fig. 1, 2).
Because European Union ask that every country from EU
has to have at least 20% from its energy generated from
renewable sources, Romania prepare itself allowing big wind
farms to be located near Black Sea coast in Dobroudgea and
beyond Danube in Romanian Plane.
For the moment, usual wind turbines have the following
geometrical dimensiones: height – 119m, diameter – 112m,
maximum height 175m.
1.1 Seismic conditions
From seismic point of view, Romania has a design code
named “
Cod de proiectare seismică – Partea 1, Prevederi de
proiectare pentru cladiri P100-2006
”. Shear base forces are
defined with:
, (1)
where:
- importance/exposal factor, depending on structure,
- response spectrum corresponding to the first
period of the structure.
total weight of structure,
correction factor.
As in can be seen in Fig. 1 seismic hazard is described through
peak ground acceleration a
g
determined for average recurrence
interval IMR=50 years for ultimate limite state: a
g
= 0,28 g ÷
0,16 g, where g=9,81m/s
2
, a
g
=2,747 ÷ 1,569 m/s
2
.
Figure 1 Peak ground acceleration according to P100-2006 and location
in Romania.
Figure 2 Corner period according to P100-2006.
