Steel-concrete composite beams
The first part of the article presents an example of calculation performed step-by-step by hand and in parallel with software automatic calculation "TraveComp" of a deck beam with a collaborating slab according to NTC 2008 and European standard EN 1994-1-1.
Let's say right away that the normative frame of reference is more complex since the same European standard EN 1994-1-1 calls other standards for verifications specifics such as EN 1993-1-5 for class 4 stiffened sections, EN 1992-1-1 for verifications to S.L.S., EN 1991-1-6 for design loads and more generally EN1993-1-1 for strength and stability verifications .
Designing structures of this type today therefore requires extensive knowledge of the European regulatory framework since the stages of construction of the work require the primary check of the steel section only when the cast concrete is not yet consolidated and then the check of the composite section under the action of permanent and service loads.
If fire resistance verification were also required, reference should also be made to EN 1994-1-2 but this is not the case in this example.
La seconda parte dell’articolo tratta la resistenza della connessione che può essere valutata con la teoria elastica (sezioni di classe qualunque) o con la teoria plastica (sezioni di classe <=2).
The stress diagrams show that the longitudinal shear force acting on the connection rungs arises from the balance of tensile and compressive stresses between the slab and steel beam. In the calculation with plastic theory, the connection is calculated at full restoration and at partial restoration.
The third part of the article presents an example of calculation performed step-by-step by hand and in parallel with software automatic calculation "TraveComp_B" according to the European standard EN 1994-1-2. The calculation of beam-slab connection with Nelson rungs under fire conditions is presented critically noting inconsistencies and possible errors in the European standard.
Steel-concrete composite beams - part 1
Steel-concrete composite beams - part 2
Steel-concrete composite beams - part 3