| Summary: | This thesis describes a time domain dynamic analysis of a proposed floating
bridge on Okanagan Lake in Kelowna, British Columbia, Canada. The analysis begins
with wave hindcasting using wind data collected at the bridge site and the nearby towns
of Penticton and Kelowna. The influence of lake geometry and bathymetry on the design
wave conditions is accounted for through the use of a numerical wave hindcasting model.
The results of the wave hindcasting model are compared with wave data collected at the
bridge site, and directional wave spectra based on the design wave conditions are then
constructed for north and south storms.
The next stage of the analysis is the calculation of wave loads on the bridge. A
computer model based on two-dimensional linear wave diffraction theory is used to
calculate the sectional hydrodynamic coefficients. Force time series are then computed
by discretizing the directional wave spectra, and combining the regular wave components
with the appropriate wave exciting force coefficients and random phases. Superposition
of these forces provides the hydrodynamic forces on the bridge as a function of time.
A structural analysis of the bridge based on the finite element method is then
conducted for north and south storms. The results of the analysis include sway, heave
and roll displacements, bending moments in the pontoons and mooring cable tensions.
Additional topics that are investigated include the influence of slowly-varying wave drift
forces on the response of the bridge, and the variability in response parameters between
simulations.
The south storm was found to provide the largest bridge response with maximum
bending moments about the z and y axes of the pontoon string of 190,000 and 290,000
kNm respectively, and a maximum cable tension of 1,670 kN. Variability between
simulations was found to be considerable, with an average coefficient of variability of
0.096 for all response parameters in 10 simulations. The slowly-varying wave drift force
was found to be equivalent to a static wave drift force at the significant wave height.
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