External beam-column joints: design to Eurocode 2

In practice external beam-column joints are seldom designed for monotonic loading. The current authors believe that this is an oversight which should be addressed. This paper presents a simple strut and tie model for the analysis and design of external reinforced concrete beam-column joints. The strut and tie model is developed from first principles using the concrete design strengths given in Eurocode 2. The main difficulty in developing strut and tie models for beam-column joints is in determining the node dimensions. The novel feature of the authors' analysis is that the joint strength is related to the flexural capacity of the beam at the face of the column which is defined in terms of the maximum moment which can be transferred through the joint into the upper and lower columns. The model is shown to give better predictions of joint shear strength than existing simple design models. A case study is presented which shows that it is often sufficient to provide only minimum shear reinforcement in beam column joints.