Autore: Fausto Minelli
Titolo: “Plain and fiber reinforced concrete beams under shear loading: structural behavior and design aspects"
Collana: Tesi e Ricerca
Genere: Ingegneria civile
The behavior and design of reinforced concrete members subjected to shear remain an area of much concern. Design codes are continually changing and generally becoming more stringent, so that structures that were designed several decades ago typically do not comply with the requirements of current codes. A total agreement on the mecha-nisms of shear transfer and on the interpretation of the collapse mode is still missing.
The present research is intended to be a further contribution to the knowledge of shear behavior in beams without transverse reinforcement.
Different materials are herein considered, in addition to plain concrete: special emphasis is devoted to fiber reinforced concrete materials, increasingly used in the practice and promising with respect to their possible application to shear-critical beams.
After a first detailed and critical review of the state of the art on shear, an extensive experimental cam-paign on twenty-seven full-scale beams is discussed, with emphasis on the effect of steel-to-concrete bond, steel fiber content (if provided), prestressing and concrete grade on the shear response of members.
The extension of a FE routine based on the Modified Compression Field Theory to fiber reinforced con-crete is evaluated and corroborated against available test results.
An analytical model for member made of plain concrete and without web reinforcement is then pro-posed, based on an assumed shear-critical crack pattern and on a self-equilibrated shear stress distri-bution.
Finally, an adaptation of the current EC2 equation for shear in members without transverse reinforcement is discussed and suitably adapted to elements containing steel fibers.
