Shrinkage (Load)

Free shrinkage strain behavior can be modeled as a load effect in reinforced concrete design and check.

Shrinkage effect is calculated as a specific rotation. The following formulas give the example of calculation for reinforced concrete slabs:

	The specific normal force causing the given shrinkage value (εcs [‰]) in the concrete zone of the section is (here in X direction).
	The position change of centre of gravity considering reinforcement bars (here X-direction; see dashed line), where   and Ss is the statical moment of (here) X-directional bars around the Y axis of the calculation plane.
	The moment around the Y axis of the calculation plane from Nx because of the position change of centre of gravity.
	The specific rotation (curvature) from My for 1 meter wide section, where  .

Definition steps

1. Set the shrinkage strain (ε_cs) value at the material properties of concrete structural elements.
   
   
   Figure: Shrinkage value of concrete materials

   Shrinkage effect is taken into consideration in RC design and check of concrete elements, which have applied reinforcement.

2. Start the  Load case command, and define one “+Shrinkage” type load-case with a name (such as “Shrinkage effect”). That means, the automatically calculated shrinkage effect is allowed on load-case level.
   
   
   Figure: Shrinkage effect added to a load case
3. Add the load case defined in the 2^nd step to load combinations/groups depending on the later RC design.