An engineering study was performed in 2017 to develop a multi-span suspension bridge on floating foundations across the Bjørnafjorden in Norway. The bridge was approximately five kilometers long and consisted of three main suspension spans supported by four pylons (towers). Two of the pylons were supported on tension-leg platforms (TLP) due to large water depths. The bridge has to be resistant towards collisions from passing ships. However, submarine impacts to the submerged parts of the bridge were also a challenge due to the bridge location being close to an active submarine training field.
This paper focus on the response of one such TLP towards collisions from submarines transiting below the bridge. Nonlinear explicit finite element analysis is used to study the possible collision scenarios, and the response of the TLP and the resulting bridge motion is evaluated. Further, transient failure of a tether was investigated to assess possible consequences of rupture of one of the tethers.