Plane of strains on the composite section

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Let's have a look at the workflow of the recalculation of internal forces on composite cross-section (obtained from FEM software) to plane of strains, which can be inserted into RCS.

Cross-section

  • Concrete grade C30/37

Construction stages

Internal forces

  • Internal forces received from the third-party software for each part of the section separately 

Plane of the strain at 28 days for component 1

  • Tangent modulus of elasticity is used for calculation. The tangent modulus is equaled to 1.05 · \(E_{cm}\).
  • Internal forces are recalculated to the center of gravity of whole cross-section (with concrete slab)

Plane of the strain at 18,250 days for component 1 - prefabricated part 

  • The curvature is recalculated to the center of gravity of the total cross-section (with a concrete slab). The normal force acting in the center of gravity of the lower (prefabricated) part is located eccentrically to the center of gravity of the total cross-section (with a concrete slab) and causes an additional bending moment.
  • An axial strain \(ε_{x1}\) at the center of gravity of the total cross-section (with concrete slab) defines the displacement of the plane of the strain calculated on the prefabricated part relative to the center of gravity of the total cross-section (with concrete slab).

Plane of the strain at 18,250 days for component 2 - composite slab

  • The curvature is recalculated to the center of gravity of the total cross-section (with a concrete slab). The normal force acting in the center of gravity of the upper part (concrete slab) is located eccentrically to the center of gravity of the total cross-section (with a concrete slab) and causes an additional bending moment.
  • An axial strain \(ε_{x2}\) at the center of gravity of the total cross-section (with concrete slab) defines the displacement of the plane of the strain calculated on the prefabricated part relative to the center of gravity of the total cross-section (with concrete slab).

Calculated plane of strains


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