Slab stiffness properties

Question

Just update RAM to V15.x and notice that there is new feature when you define deck/slab property information in ram modeler. Could you provide explanation on how "slab stiffness properties" input apply to diaphragm properties?

Seth Guthrie · Answer

From the RamModeler.pdf help file: 
 Stiffness modifiers can be used to modify the stiffness in different directions and actions (in-plane and out-of plane). These can be used to assign different properties for corrugated decks such that load is only transferred along the deck direction. Similarly, they can be used to account for cracked properties of concrete decks (in place of crack factors). For noncomposite floor and concrete slab systems, you may also specify the angle from the global X-axis at which the stiffness modifiers act. To modify stiffness properties of diaphragms, the program allows you to define 3 stiffness modifiers for in-plane action (i.e., f11, f22, and f12) and 3 stiffness modifiers for out-on-plane action (i.e., m11, m22, and m12). Further information can be found in RAM Frame Manual, Section 6.24.