DNV DNV-CG-0447 PDF

This class guideline describes the procedure for fatigue strength assessment of lashing bridges and their ship-side foundations taking into account the effect of global vibration of lashing bridges caused by the main engine and propeller excitation. This procedure comprises:

— lashing bridge free vibration analysis, see Sec.3 [4]

— lashing bridge forced vibration analysis for relevant excitation orders of main engine and propeller forces, see Sec.3 [5]

— fatigue strength assessment of lashing bridge and ship-side foundation structure considering vibrationinduced stresses, see Sec.4.

The analysis scope should cover following lashing bridges as a minimum:

— the aft most lashing bridge with the design typical for the ship under consideration

— lashing bridges significantly deviating from the typical design with respect to the expected vibration behaviour, e.g. the two aft most lashing bridges and the lashing bridge immediately aft of the funnel.

Lashing bridges may be selected for vibration and fatigue analysis upon agreement with the Society.

The assessment of local vibrations of secondary structural members of lashing bridges like platforms, plate fields, stiffeners and hand rails is not covered by this guideline.