Seismosoft | Earthquake Engineering Solutions

Dear Seismosoft,

When I use the infrmFB element formulation, Should I check ¡°carry out stess recovery¡± in project settings?

In additon,when I add the damping to the structual analysis model,and there are two options: in element classes and in damping of project settings,then should I define the damping only in the element level respectively or define the damping only in the total damping of project settings or define the damping in both the element level and the total damping of project settings?

Best regards

Hi,

1) if your "primary need" is to obtain the exact values of internal forces, then you have to check the "Carry out Stress Recovery" box even if you are employing infrmFB elements (see 'Theoretical background...'->'Material inelasticity' and also 'Project Settings'->'Elements'->'Carry out Stress Recovery' and 'Notes')
2) regarding the damping options, it depends on what you are interested in. In the "Project settings" menu you define the "global damping" of your structure, whereas in the "element classes" menu you define the "element-specific damping"

Federica

Hi Federica,

Thanks very much for your reply.
Currently I am carrying out some nonlinear dynamic time-history analysis of multi-storey frame, and I am interested in the exact values of internal forces and the local response of the ends of structural member. So for a normal multi-storey frame which consist of reinforced concrete beam, column and slab, should I define the damping only in the total damping of project settings or...?

Best regards

Hi,

in your case (reinforced concrete structure) I suggest to define the "global" damping (Project Settings -> Damping). As suggested in the Help System, values of 2-3% viscous damping (using tangent stiffness-proportionality) are reasonable.

Federica