Moment–rotation relationship of RC beam-column connections: Experimental tests and analytical model

This paper presents experimental results on the moment–rotation behavior of reinforced concrete beam-column connections as well as a simple analytical model to predict this curve for structural design purposes. The parameters considered by the proposed model are the relative slip of the flexural reinforcement in the joint and the slip induced by flexural cracking of the beam end. A new procedure based on the evaluation of the crack width inside disturbed regions (D-regions) was used to calculate the rotation resulting from the cracking of the beam. Adaptations and simplifications were performed aiming to turn the analytical model suitable for numerical modeling of the non-linear behavior of reinforced concrete frames. The moment–rotation curves given by the proposed model were compared to the experimental curves given by the tests. Additionally, the proposed curves were included in a software program based on the finite element method, allowing comparisons between theoretical and experimental results for vertical displacements of the beams. The obtained results showed a good agreement with the tests.