Completed Projects

Below brief descriptions of the completed projects are given. For further reading click on "read more", which will guide you to a more detailed summary including a list of publications made in connection with this project. For more information please contact the supervisor(s) of the respective project.

 

Type: M.Sc. Project

 Period: April.2010 - Nov.2010

  Penang Bridge

 

Fatigue of Monostrand High-Strength Steel Cables under Bending

Students: Agnieszka Kotas, Jan Winkler
Supervisor(s): Gregor Fischer, Christos Georgakis 
Industrial Partners: DYWIDAG (DSI International), ATKINS A/S

Description: The performance of high strength steel cables is commonly evaluated by following the experimental procedures outlined by fib, PTI and SETRA. For fatigue performance, experiments are required, in which the cable is excited axially and sinusoidally, with and without angular anchorage deviations (representing construction faults). Unfortunately, the proposed test procedures often do not simulate actual conditions, in which the cable is might be subjected to bending, due to wind loading, parametric excitation or other forms of dynamic loading.    

The goal of the current project is to address the aforementioned evaluation deficiency, by testing a series of post-tensioned high-strength steel monostrands under various levels of mid-span sinusoidal lateral displacements - with angular anchorage deviations. Cumalitively, the results from the test series should lead to preliminary S-N (fatigue) curves, for the evaluation of monostrand cable life expectancy - something which is currently unavailable in the literature.

  Type: Master Project 
Period: Sep.2009 - Mar.2010

Gold Coast Skryskraber

Influence of Wind Load Simulation on the Prediction of Horizontal Acceleration Level of High-Rise Structures

Students: Christian Ulrich Barfoed , Jakob Hauberg
Supervisor(s): Holger Koss, Jeppe Jönsson
Collaboration partner: FORCE Technology, Department of Hydro and Aerodynamic

Description: The project focuses on the determination of horizontal acceleration in high-rise building structures used to asses the human occupant comfort. Three proven classic methods will be considered, all of them based on wind tunnel testing techniques. The project shall investigate the main differences in result between the methods and the effect on the occupant comfort assessment, applying all known assessment approaches. The considered methods, or testing techniques respectively, are:

  • Simultaneous high-frequent surface pressure measurements at discrete points (pressure model)
  • High-frequency force balance technique (HFFB).
  • Aero-elastic model testing (option)

Parallel to the comparative study the actual testing techniques shall be reviewed with respect to accuracy and proper performance. Further comparison shall be made to code-based and database methods to estimate the dynamic along-wind response of high-rise building structures.

Keywords: High-rise building; wind tunnel testing; high-frequency force balance; pressure measurements; aero-elastic model; human comfort to building motion.

 

Type: Master Project 

Period: Mar.2009 - Aug.2009

Store bælt Bridge Caple

Vibration control of Bridge Cables

Student: Kenneth Kleissl
Supervisor(s): Christos Georgakis, Holger Koss
 
Description: In this project, the viability of modifying cable shape and surface has been examined for the elimination of wind-induced vibrations. An experimental investigation has been carried out in a high-speed wind tunnel facility for cylinders, with different passive flow improvements, such as shrouding, waviness and faceting, including a circular cylinder for reference. The cylinders were tested in a static inclined setup, allowing the cylinder to be installed at a yawed position and with all tests conducted at both smooth and turbulent flow conditions. The aerodynamic damping has been evaluated by applying instability models based on the quasi-steady theory. While the other cylinders suffered from dry inclined galloping, Drag Crisis, or Den Hartog galloping, the shrouded cylinder was found as the only solution capable of completely suppressing any form of instability risk, but at the cost of a slight increase in drag at the design wind speed (read more).

Keywords: Wind tunnel testing; aerodynamic force coefficients; aerodynamic damping; comparison to literature.
 

Type: Master Project 

Period: Aug.2008 - Feb.2009

Lattice Mast

Aerodynamic Coefficients of Lattice Telecommunication Masts

 

Student: Marie Johnsen
Supervisor(s): Christos Georgakis, Holger Koss
External supervisor: Mogens G. Nielsen (Rambøll)

 

 

Description: The project investigated the aerodynamic load coefficients on full-size section of lattice masts used for telecommuncation structures. The aim was to evaluate whether load coefficients given in literature are too conservative, since determined on models at reduced scale. To conduct the study, a large test rig was designed to mount full-size mast sections. Due to the large size the aerodynamic tests were performed at VELUX' wind tunnel facility in Øsbirk (read more).

Keywords: Wind tunnel testing; aerodynamic load coefficients; full-size sections; comparison to literature

 
Updated by Holger Koss on 9 December 2014
Responsible editor: Holger Koss
Updated by Holger Koss on 9 December 2014
Responsible editor: Holger Koss