The relevant parameters for dynamic calculations in RM Bridge Enterprise are set in the Recalculation Window at the Dynamics / Iteration options within the Dynamics group. They are:

g - gravity (constant acceleration of gravity)

dt - time step (length for Time History - TH)

c1 - delta integration constant (for Newmark time integration method)

c2 - alpha integration constant (for Newmark time integration method)

Alfa - Mass coefficient (for damping matrix)

Beta - Stiffness coefficient (for damping matrix)

Xsi - Global damping ratio of actual to critical (for modal superposition)

Tol - Mass tolerance (for natural modes)

RM mode superposition method - to get the maximum of all components of the result vector independently from each other (with a factorized natural mode) 

communities.bentley.com/.../rm-bridge-analyzer-recalculation-window