A Dynamic Analysis of Wave Forces on Guyed Instrument Towers

A three-dimensional computer model to simulate the dynamic responses of small guyed towers, loaded with scientific equipment, to wind and wave forces has been developed to aid the tower designer. The wave forces for any combination of waveheight and wavelength were calculated from linear wave theory and applied to a NASTRAN package program. This model is unique in that it calculates the natural frequencies, displacements, forces and accelerations of the structure under the effects of the non-linear behaviour of guy cables acting simultaneously with the wave forces. Three types of guyed towers used in the Great Lakes were analysed using this technique. Guy wire tensions were measured under actual wind and wave conditions in Lake Ontario on two of the tower configurations. The recorded data, compared with the responses predicted by the model, provide some valuable insight into the behaviour of guyed instrument towers.