Self-Constraint Force & Stress

In steel-concrete composite beams, due to compatibility conditions, creep and shrinkage of concrete part of the cross-section (concrete slab) results in a redistribution of stresses. When deformation of shortening happens in the concrete part, the steel part of the cross-section prevents free deformation of concrete. As a result of restrained deformation, tensile stresses appear in concrete slab, Due to equilibrium, compressive stresses in the steel part of cross-section appear as well.  Also, these self-restraint stresses of composite sections can occur due to nonlinear temperature gradient in the cross-section. This kind of self-restraint stresses of composite sections can be checked in a table in the form of Spread Sheet. The ‘Self-Constraint Force & Stress’ table will be inactivated if the ‘Self-Constraint Forces and Stresses’ option in the ‘Construction Stage Analysis Control Data’ dialog is checked off.

Table Tool in midas Civil offers a variety of powerful built-in functions. Refer to Usage of Table Tool for detail directions:

From the Main Menu select Results > Result Tables > Composite Section for C.S. > Self-Constraint Force & Stress

Refer to "Construction Stage Analysis Control"

Refer to Usage of Table Tool and check the following data

Beam Force

Elem: Element number

Load: Unit load case/combination

Stage: Construction stage

Step: Sub-stage

Section Part: Part Number in composite section

Part: Output position along the length of each element

Axial: Self-restraint axial force

Moment-y: Self-restraint bending moment about the element's local y-axis

Moment-z: Self-restraint bending moment about the element's local z-axis

Beam Stress

Elem: Element number

Load: Unit load case/combination

Stage: Construction stage

Step: Sub-stage

Section Part: Part Number in composite section

Part: Output position along the length of each element

Axial: Self-restraint axial stress

Bend(+y): Self-restraint bending stress due to moment about the element's local z-axis

Bend(-y): Self-restraint bending stress due to moment about the element's local z-axis

Bend(+z): Self-restraint bending stress due to moment about the element's local y-axis

Bend(-z): Self-restraint bending stress due to moment about the element's local y-axis

Cb(min/max): Max. combined self-restraint stress among the absolute values of Cb1, Cb2, Cb3 and Cb4

Cb1(-y+z): Axial + Bend(-y) + Bend(+z)

Cb2(+y+z): Axial + Bend(+y) + Bend(+z)

Cb3(+y-z): Axial + Bend(+y) + Bend(-z)

Cb4(-y-z): Axial + Bend(-y) + Bend(-z)

Cb Cent: Combined self-restraint stress at the centroid of concrete