Nomograms for the pre-dimensioning of RC beam-column joints according to Eurocode 8

Beam-column joints in reinforced concrete frame buildings are very important elements whose design must be done with particular attention to guarantee the development of full strength and ductility of structural elements, as well as the respect of the hierarchy principles. Nowadays many codes worldwide require the evaluation of the beam-column joint capacity and provide expressions for the verification of this fundamental element. The respect of these verifications may lead the designer to take decisions which can affect, even significantly, the structural component geometry and also the architectural design of buildings. In this paper a simple and fast-to-use graphical tool is provided to support the design of beam-column joints satisfying Eurocode 8 verification expressions. In detail, nomograms are proposed with the great advantage of being largely applicable for all types of beam-column joints. The use of nomograms makes it possible to obtain an estimation of the beam-column joint sizing and of the horizontal hoop amount. If the joint dimension reveals to be underestimated and/or the hoop amount leads to an excessive close spacing, the designer can promptly modify the design at the early stages of the design process. Worked examples are also proposed, and many types of nomograms are reported in a dedicated appendix.