Issue 16

This paper is part 1 of two papers dealing with the semi-rigid behaviour of beam-to-column connections in precast concrete framed structures. In Part 1, the results of 28 full scale tests are presented. In Part 2, equations are presented to predict moment–rotation behaviour, together with a method to calculate the effective length factors for columns in semi-rigid sway frames. Connections were made using proprietary pinned jointed billet, cleat and welded plate connectors, to form cruciform assemblages subjected to sway and gravity load. They were not purposefully intended as moment resisting. In some cases 200mm deep hollow cored slabs and high tensile reinforcement completed the connections. Although the moment of resistance of the connections varied from 11 to 239kNm, and flex-ural stiffness from 200 to 27 000kNm/radian, when the test results are normalised with respect to the capacity of the beams there is remarkable correlation leading to several useful parametric equations. Designers are therefore able to calculate the moment and stiffness values which provide the input data in the frame stability analysis described in Part 2. Kim S. Elliott, BTech, PhD, CEng, MICE School of Civil Engineering, University of Nottingham, UK Gwynne Davies, BSc, PhD, CEng, MIStructE, MICE School of Civil Engineering, University of Nottingham, UK Marcelo Ferreira, MEng, MSc, PhD, CEng University of Sao Paulo, Brazil Formerly Post-Doctoral Researcher, Dept of Civil Engineering, University of Nottingham, UK Halil Gorgun, BSc, MSc, PhD Lecturer, Dicle University, Turkey Formerly Research Assistant, Dept of Civil Engineering, University of Nottingham, UK A. A. Mahdi, BSc, MSc, PhD, MICE Hyder Consulting, UK Formerly Research Assistant, Dept of Civil Engineering, University of Nottingham, UK

This is Part 2 of a paper dealing with the semi-rigid behaviour of connections in precast concrete framed structures. In Part 11 the results of 28 full scale beam-to-column connection tests were presented in terms of flexural strength and stiffness. In Part 2, equations are developed to predict moment-rotation (M–f) behaviour, and a method to calculate the effective length factors b for columns in sway frames containing semirigid connections is presented. The moment of resistance of the connection MRC is the sum of the yield strength of all components present at the end of the beam. The mean value of the ratio of the calculated-to-test moment is 1.01. Connection rotation is the aggregate sum of deformations at the interface, plus beam and column curvature acting over a length related to the dimension of the beam or column. The correlation with experimental M–f curves is in some cases better than 95% accurate. The analysis shows that whilst some connectors are suitable for semi-rigid frame design, non-compliant ones should be classified as pinned. The semi-rigid behaviour of precast beam-column connections and the axial load capacity of columns can be obtained through rational calculations. Kim S. Elliott, BTech, PhD, CEng, MICE School of Civil Engineering, University of Nottingham, Gwynne Davies, BSc, PhD, CEng, MIStructE, MICE School of Civil Engineering, University of Nottingham, UK Marcelo Ferreira MEng, MSc, PhD, CEng University of Sao Paulo, Brazil Formerly Post-Doctoral Researcher, Department of Civil Engineering, University of Nottingham Halil Gorgun, BSc, MSc, PhD Lecturer, Dicle University, Turkey Formerly Research Assistant, Department of Civil Engineering, University of Nottingham, UK A. A. Mahdi, BSc, MSc, PhD, MICE Hyder Consulting, UK Formerly Research Assistant Department of Civil Engineering, University of Nottingham, UK