Kartlegging
Global Response from Drydocking of Pontoons Concept Development, Floating Bridge E39 Bjørnafjorden
The effect of attaching a drydocking barge to a pontoon to the Bjørnafjorden bridge for maintenance operations has been assessed in this report. The barge is assumed to be rectangular with main dimensions (LxBxDxH) 70x31x16x22m and a displacement of 34700 tons. The displacement of the barge is equivalent to approx 30% of the displaced mass of the total bridge and is therefore assumed to affect the global response of the bridge considerably. The barge has been modelled in Wamit and hydrodynamic coefficients have been found, which have been used for global analysis in Orcaflex. Four representative barge locations have been assessed (A3, A13, A24 and A40). The presence of the drydock disturbs the bridge modes and response significantly. Strong-axis response may be improved during drydocking, but weak-axis response is deteriorated. Tidal effects increase towards either end due to the increased waterplane area. The analysis reported in this document indicate that the proposed drydock method for dry access for maintenance of pontoons is a feasible option.