I have a two-part question concerning design strips and cracked/uncracked behavior for vibration analysis.
Design Strips for Vibration Analysis
I am analyzing a one-way concrete slab with post-tensioned concrete girders spanning longitudinally, and concrete joists at 3'-0" on center spanning latitudinally. Is this the correct design strip input? My ultimate goal is to perform a vibration analysis. Do the design strips have an impact on the vibration analysis?
Latitude Cross Sections Perspective:
Longitude Cross Sections Perspective:
Cracked/Uncracked Behavior for Vibration Analysis
By clicking Criteria-Calc Options-Vibrations, there is an option to select a stiffness matrix. If I select Global Stiffness Matrix, it is my understanding that the analysis will be based on gross uncracked cross section properties if the slab or beams is defined with stiffness modifiers equal to 1.0. If I want the analysis to be based on cracked cross section properties, I need to set the Behavior to "Custom" and the flexural stiffness factors to less than 1.0.
However, I noticed in the RAM Concept Manual that I may use the design strips to define a cross section as cracked/uncracked. How do these two forms of input work with each other? Do I need to ensure both match for the program to analyze the slab or beam as cracked/uncracked?
From the RAM Concept V8i (SELECTseries 8) Manual:
Thank you for your help!