• Per Kjærsgaard Andersen
  • Phu Do Tran
4. term, Structural and Civil Engineering, Master (Master Programme)
In this project the dynamic response of Light*House due to wind loads has been investigated. This includes the modeling of the carrying and stabilizing structure, the ground and the wind load. The structure is modeled by means of the finite element method. First a beam representation based on Bernoulli Euler finite elements is introduced. This model has been programmed by the project group itself and can to a large extend be configured to represent a given three‐dimensional structure. In this regard it has been investigated what the influence of the mass modeling of the floor decks is in terms of lumped masses versus equally distributed masses. After this the structure has been modeled by means of plate finite elements in Abaqus where eigenmodes and –frequencies has been determined. This model is introduced in order to explore what the more realistic plate model means to the results in terms of stiffness and mass distribution. The windload has been modeled by means of two different approaches. First the main purpose has been to introduce a load model which is directly dependent on the response of the structure. The choice of load model is the Wake model, which has been developed to predict forces caused by current on offshore pipelines. Therefore this model has little physical justification for high rise buildings like Light*House. After this a two‐dimensional CFD model has been used to investigate how different physical aspects influence the load series on the structure. Here it has been explored which main components the windload consists of. This has been done for both a circular crosssection and a parallelogram. The results of these analyses has been calibrated to mathematical expressions and implemented in the computer program developed by the project group. The interaction between the structure and the ground has been modeled infinitively stiff. After this it has been attempted to implement the so‐called Lumped Parameter Model which models the impedance of the ground by means of discrete mechanical systems. Unfortunately this has not been achieved due to lack of time in the last days of the project period. The documentation of the theories used in LPM has been included in the thesis, however.
Publication date2008
Number of pages151
Publishing institutionAAU, byggeri og anlæg
ID: 14465675