Q. Calculation of seismic response loads?
The seismic design requirements and the specification of criteria variables for the calculation of seismic response loads for the design of vessels. The calculation of seismic forces for vessels is governed by one of two methods.
The first step in an analysis is to perform an eigenvalue analysis of the vessel, in order to calculate its first natural period (horizontal direction, in the installed position). This is done by dividing the vessel into an appropriate number of mass and stiffness elements, per the theory of structural dynamics. The mass points are numbered, starting at the first point above grade for vertically oriented vessels. For horizontally oriented vessels, only one mass point is normally required because the vessel has the center of gravity of the majority of its mass concentrated at one level above the ground.