Concrete Deflection

The physically non-linear properties of the reinforced concrete sections are taken into account. This is somewhat more complicated than for timber, because the EI's vary over the length: the longitudinal reinforcement can differ and the sections can be cracked or uncracked.

How is the calculation performed?

The beam is divided into member parts / segments. For each segment it is determined which longitudinal reinforcement (top and bottom) is present there, and the stiffnesses (short duration and long duration) are determined on the basis of M-kappa diagrams. Separate force distributions are made with those different EI's per segment (short duration and long duration). (So no integration of curvatures, but additional structural analyses with many members.)

This is an accurate calculation. Cantilevers can also be calculated easily in this way. You can therefore favourably influence the deflection by placing local additional reinforcement.

Deflections

• w-on is the directly occurring deformation with short duration EI;G;on
• w-kruip is the deformation due to creep. It is calculated in the quasi-permanent combination. Two force distributions are calculated. Once with the short duration EI;qp;kort and once with the long duration EI;qp;lang. The difference is the increase due to creep. w-kruip = w;qp;lang - w;qp;kort
• w-k is the occurring deformation in the SLS with short duration EI;k
• w-tot,k = wk + wkruip
• w-bij,k = wk + wkruip - won