The prediction of moment-rotation curves of extended endplate connections for use in semi-rigid analysis of steel frameworks

Methods of analysis which incorporate the semi-rigidity of connections already exist. At present, the only way of providing the reliable connection moment-rotation data required for these analyses is by conducting expensive full-scale testing of connection subassemblies. There is a need for methods of prediction for all types of steel framework connections. In this study a method of predicting the behaviour of extended endplate connections has been presented. Connections are classified according to their position in the steel framework and the geometry of the individual connection. A review of existing full-scale tests on extended endplate connections is given along with a review of the existing mathematical models used to represent connection behaviour. An existing physically based moment-rotation model has been taken and some of the parameters are recalculated. In particular a more rigorous representation of the column flange in the tension region of the connection has been derived. An outline of the calculation of the parameters for the potentially different behaviour of connections due to their position in the framework is given. A series of 13 full-scale tests on internal/internal extended endplate connection specimens has been carried out. Four different methods of connection rotation measurement have been used throughout the study. The best method of measurement is a transducer based method which allows the contribution of the various connection components to overall connection rotation to be assessed. The moment-rotation curves obtained are compared and evaluated. The proposed method of prediction compares favourably with most experimental results. A plane semi-rigid framework analysis program has been written by the author so that the effect of using predicted and experimentally obtained moment-rotation curves on framework behaviour can be established. This program has also been used to predict the behaviour of a full-scale plane frame test carried out at BRE by Hatfield Polytechnic. The connection curves used in this analysis have been derived using the prediction method. The results of the frame analysis are compared with the experimental values and agreement is found to be satisfactory. It is concluded that moment-rotation curves of internal/internal extended endplate connections can be predicted with sufficient accuracy for use in the semi-rigid analysis of steel frameworks. Recommendations for further research include more experimental work on different classes of extended endplate connections and applying the physically based mathematical model which has been used to different connection types