Study of the effect of skewed beam-to-column connections on loss of strength in endplate moment connections

Document Type : Research Article


Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran


Skewed beams may be utilized due to the architectural limitations. The use of skewed beam cause to initiation of torsional moment, in addition to flexural moment, at the connection face. In the beams with end plate connections, the torsional moment creates shear stress at the end plates which in combine with the shear stress due to connection shear force can lead to reduction in the connection frictional strength and the end plates slippage. This paper investigates the slippage of the end plates of skewed beam with rigid connection to columns with end-plates. 122 finite element non-linear models are used to study the end plate moment connections with skewed beams with 10, 20, 30 and 45 degree of deviation in the plan. The results showed that for the beams with low degree of deviation, the addition of one or two rows of bolts is a suitable method for reducing the loss of strength for skewed beams. For high deviation angle of 45 degree the friction strength loss is considerable and so large number of bolts may be required to be added to recover the friction strength loss, which may not be possible due to the geometric limitations of the connection and so it is recommended in the beams with 45 deviation angle other types of connections to be used.


Main Subjects

[1] N.B.R.o. Iran, Design and Construction of Steel Structures,Ministry of roads and Urban developement, Deputy for Housing and Constructions, 2013(in Persian).
[2] M. Zarean, B. Hoseini Hashemi, M. Hoseini, Seismic behavior of rigid connection of oblique beam in plan to steel box column with use of top and bottom cover plates, 4th National Conference on Steel and Structures, Iranian Society of Steel Structures, Tehran, 2013(in Persian).
[3] A. Fiouz, M. Mahini, A. Ahmadi, Study of seismic behavior of oblique beams with reduced beam section with different angles, 3th International Congress on Civil Engineering, Architecture and Urban Development, Tehran, 2015(in Persian).
[4] W.A. Thornton, L. Kloiber, Connections for skewed beams, North American Steel Construction Conference, Modern Steel Construction, 1999.
[5] AISC, Steel Construction Manual,14th ed, American Institute of Steel, 2011.
[6] M. Al Hijaj, M. Mahamid, Behavior of skewed extended shear tab connections part I: Connection to supporting web, Journal of Constructional Steel Research, 128(Supplement C) (2017) 305-320.
[7] M. Mahamid, M. Al Hijaj, Behavior of skewed extended shear tab connections part II: Connection to supporting flange, Journal of Constructional Steel Research, 128(Supplement C) (2017) 462-472.
[8] M. Al Hijaj, M. Mahamid, Behavior of Skewed Extended Shear Tab Connections, Structures Congress 2015.
[9] M. Mahamid, M. Al Hijaj, Behavior of Stiffened Skewed Extended Shear Tab Connections, Geotechnical and Structural Engineering Congress, 2016.
[10] A. Zareia, M. Vaghefi, A.R. Fiouz, Numerical investigation seismic performance of rigid skewed beam-to-column connection with reduced beam section, Structural Engineering and Mechanics, 57(3) (2016) 507-528.
[11] Y. Shi, G. Shi, Y. Wang, Experimental and theoretical analysis of the moment–rotation behaviour of stiffened extended end-plate connections, Journal of Constructional Steel Research, 63(9) (2007) 1279-1293.
[12] AISC360, Specification for structural steel buildings: American Institute of Steel Construction, AISC, 2010.
[13] Ansys Workbench, 2016.
[14] AISC358, Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications, AISC, 2014.
[15] C.G. Salmon, J.E. Johnson, F.A. Malhas, Steel Structures: Design and Behavior, 5th Edition ed., Pearson International Edition, 2009.