How does ETABS handle the lateral stiffness of filled and unfilled decks?
For unfilled decks, ETABS only considers the deck material and deck shear thickness for the stiffness matrix. These values can be found under Define>Deck sections>modify/show properties. For filled decks, ETABS determines the stiffness by the values of the slab depth and the properties of the concrete. Different stiffnesses are used for the 2 deck directions i.e. along the flutes and orthogonal to the flutes becuase of different thicknesses of concrete fill. 6. Is the deck considered an isotropic material or will there be different stiffnesses in each direction? ETABS considers the deck as an isotropic material. Isotropic behavior is usually assumed for steel and concrete, although that is not always the case. The behavior of an isotropic material is independent of the direction of loading. In addition, the shearing behavior is uncoupled from the extensional behavior and it is not affected by temperature change.
