An improved polynomial model for top -and seat- angle connection

  • Prabha, P. (Strucutural Engineering Research Centre, CSIR campus) ;
  • Marimuthu, V. (Strucutural Engineering Research Centre, CSIR campus) ;
  • Jayachandran, S. Arul (Strucutural Engineering Research Centre, CSIR campus) ;
  • Seetharaman, S. (Strucutural Engineering Research Centre, CSIR campus) ;
  • Raman, N. (Flour Daniel India Limited)
  • Received : 2007.09.11
  • Accepted : 2008.07.16
  • Published : 2008.10.25


The design provisions for semi-rigid steel frames have been incorporated in codes of practice for steel structures. In order to do the same, it is necessary to know the experimental moment-relative rotation (M-${\theta}_r$) behaviour of beam-to-column connections. In spite of numerous publications and collection of several connection databases, there is no unified approach for the semi-rigid design of steel frames. Amongst the many connection models available, the Frye-Morris polynomial model, with its limitations reported in the literature, is simple to adopt at least for the linear design space. However this model requires more number of connection tests and regression analyses to make it a realistic prediction model. In this paper, 3D nonlinear finite element (FE) analysis of beam-column connection specimens, carried out using ABAQUS software, for evaluating the M-${\theta}_r$ behaviour of semi-rigid top and seat-angle (TSA) bolted connections are described. The finite element model is validated against experimental behaviour of the same connection with regard to their moment-rotation behaviour, stress distribution and mode of failure of the connections. The calibrated FE model is used to evaluate the performance of the Frye-Morris polynomial model. The results of the numerical parametric studies carried out using the validated FE model have been used in proposing modifications to the Frye-Morris model for TSA connection in terms of the powers of the size parameters.


semi-rigid analysis;top and seat-angle connection;Frye-Morris polynomial model, Moment-relative rotation (M-${\theta}_r$)


  1. Nethercot, D.A. (1985), Steel beam-to-column connections - A review list of test data, CIRIA, London.
  2. Prabha, P. (2007), "Finite element analysis of beam-column connections", M.E thesis, Thiagarajar college of Engineering, Madurai.
  3. Pucinotti, R. (2001), "Top and seat and web angle connections: Prediction via mechanical model", J. Construct. Steel. Res., 57(6), 663-696.
  4. Raman, M. (2005), "Analytical & Experimental investigations on semi-rigid steel connections", M.E thesis, Malnad college of Engineering, Hassan.
  5. Taufik, S., and Xiao, R.Y. (2005), "3D finite element prediction of angle bolted connection with high strength steel", Advances in Steel Structures, 2, 1775-1782.
  6. Chen, W.F. and Kishi, N. (1989), Semi-rigid steel beam-to-column connections: database and modeling, ASCE, 115(ST1), 105-119.
  7. Citipitioglu, A.M., Haj-Ali, R.M., and White, D.W. (2002), "Refined 3D finite element modeling of partially restrained connections including slip", J. Construct. Steel. Eng., 58, 995-1013.
  8. Dhillon, B.S., and O'Malley. (1999), "Interactive design of semi rigid steel frames", J. Struct. Eng., ASCE, 125(5), 556-564.
  9. Driscoll, G.C. (1987), "Elasto plastic analysis of top and seat angle connections", J. Construct. Steel Res, 8, 119-135.
  10. Frye John, M., and Morris, A. Glenn. (1975), "Analysis of flexibility connected steel frame", Canadian Journal of Civil Engineering, 2, 280-291.
  11. Goverdhan, A.V. (1983), A collection of Experimental Moment-Rotation curves and Evaluation of prediction equations for Semi-Rigid connections, M.S thesis, Vanderbilt University, Nashville, TN.
  12. Hechtman, R.A., and Johnston, B.G. (1947), Riveted Semi-Rigid Beam-To-Column connections, Progress Report No. 1, AISC Research at Lehigh University, Bethlehem, PA.
  13. Hong, K., Yang, J.G., and Lee, S.K. (2002), "Moment-Rotation behaviour of double angle connections subjected to shear load", Eng. Struct., 24, 125-132.
  14. IS: 800 (draft code Limit state method) (2005), Code of practice for general construction in steel, Bureau of Indian Standards, New Delhi.
  15. Kim Yosuk., and Chen, W.F. (1998), "Practical analysis for partially restrained frame design", J. Struct. Eng, 736-749.
  16. Kishi, N., Ahmed, A., and Yabuki, N. (2001), "Nonlinear finite element analysis of top- and seat-angle with double web-angle connections", Struct. Eng. Mech, 12(2), 201-214.
  17. Kishi, N., and Chen, W.F. (1990), "Moment-Rotation Relations of Semi-rigid Connections With Angles", J. Struct. Eng, 116(7), 1813-1834.
  18. Kishi, N., Hassan, R., Chen, W.F., and Goto, Y. (1997), "Study of Euro code 3 Steel Connection Classification", Engineering Structures, 19(9), 772-779.
  19. Kishi. N., and Chen, W.F. (1986), Database of steel beam-to-column connections, CE-STR-86-26, School of Civil Engineering, Purdue University, West Lafayette, IN.
  20. Abdalla, K.M., and Chen, W.F. (1995), "Expanded Data Base of Semi-Rigid Steel Connections", Comput. Struct., 56(4), 553-564.
  21. Barakat Munzer and Chen, W.F. (1991), "Design Analysis of Semi-Rigid Frames: Evaluation and Implementation", Engineering Journal/AISC, 2nd quarter, 55-64.
  22. Komuro, M., Chen, W.F., and Kishi, N. (2004), "Elasto-plastic FE analysis on moment-rotation relations of top- and seat-angle connections", Connections in Steel Structures, Amsterdam, The Netherlands, June 3-4, 111-120.
  23. Lee, S.S., and Moon, T.A. (2002), "Moment rotation model of semi rigid connections with angles", Eng. Struct, 24(2), 227-237.
  24. ABAQUS (2006) users' manual, Hibbit Karlsson & Sorensen, Inc.

Cited by

  1. Numerical Estimation for Initial Stiffness and Ultimate Moment of Top-Seat Angle Connections without Web Angle vol.143, pp.10, 2017,
  2. Optimum design of geometrically non-linear steel frames with semi-rigid connections using a harmony search algorithm vol.9, pp.6, 2009,
  3. Modified Frye–Morris polynomial model for double web-angle connections vol.7, pp.3, 2015,
  4. Moment-Rotation Model for Blind-Bolted Flush End-Plate Connections in Composite Frame Structures vol.141, pp.9, 2015,