On shear reinforcement design of structural concrete beams on the basis of theory of plasticity

Abstract

Modern design of reinforced concrete structural members for shear is based on the theory of plasticity. This paper is written to contribute to the understanding of the inclination of the concrete strut in the inclined strut model for design of shear reinforcement in beams, which among others are used in Eurocode 2. The problem of inclination of the compression strut in truss model is analysed depending on shear reinforcement ratio and effectiveness ratio of concrete strength for compression. Also the understanding of necessary ductility in steel reinforcing bars is discussed in the paper and especially the needs of tests on translation capacity of the shear failure are here analysed. To explain these problems the paper gives a short introduction to the theory of plasticity of reinforced concrete in shear and the background for the equations, which are used in shear design according to Eurocode 2.

Santrauka

Šiuolaikinis gelžbetonio elementu skersinjs armatūros skaičiavimas pagristas plastiškumo teorijos principais. Straipsnyje pateikti siju skersinjs armatūros skaičiavimo ypatumai, taikant istrižojo statramsčio modeli, kuris taikomas ir Eurokode 2. Išnagrinjtas gniuždomojo strypo pavertimas santvaros modelyje, atsižvelgiant i skersinjs armatūros ir efektyvaus gniuždomojo betono stiprio santyki. Aptartas armatūrinio plieno strypu stamantrumas, akcentuota siju laikomosios galios šlyčiai eksperimentiniu tyrimu būtinybj. Pateiktas gelžbetoniniu siju šlyties skaičiavimas, taikant plastiškumo teorijos principus. Aptartas Eurokode 2 šlyties skaičiavimams taikomu priklausomybiu teorinis pagrindas.

Keywords:

• RC beams
• shear design
• plasticity of concrete
• stringer method
• inclined crack width

Reikšminiai žodžiai::

• gelžbetoninjs sijos
• projektavimas šlyčiai
• betono plastiškumas
• ilginio metodas
• istrižojo plyšio plotis