Keywords: semi-continuous connection, high strength steel, finite element, connection behaviour, spring stiffness.

A three dimensional numerical modelling procedure for the analysis of semi continuous composite connections with high strength steel is herein presented. In this paper, the rigorous application of the finite element computing package ANSYS has been used to investigate the connection behaviour. Non-linear 3D continuum elements of concrete, steel and shear connectors are used to model the connection. The proposed models are compared using a simplified approach using spring stiffness analysis. From these models it will be possible to establish suitable design methods utilising the strength and stiffness of semi-continuous composite connections with high strength steel. In this study, a 3D modelling of semi-continuous composite connection with flush end plate are performed recognizing contact effects and bolt geometry. Since the material non-linearities, contact surface and bolts most important parameters, therefore the connection and stiffener require considered model as accurate as possible. The connection model is considered to mostly employ shell elements for major parts of the connection i.e beam, column and end plate. The modelling approach is still required simplifications in order to reduce the computational effort. The finite element of the connections is then presented and the results are compared with the previous test data [1], and finally the behaviour of the connection with high strength steel is predicted. In order to obtain the connection efficiency, a flush end plate (FEP) connection with no stiffener is compared with the FEP connection with stiffened column. Moment capacity and connection behaviour due to a high strength endplate on the connection are determined. A non-linear connection model is symmetric about the centre of the column web and no lateral displacement is assumed, so only one side of the plane of symmetry is modelled. A symmetry boundary condition is applied to reduce the size of the model. A multilinear elastic-plastic approach is used to determine the material properties of high strength steel for the finite element (FE) model, whilst the yield stress is defined as 0.2% proof stress. The initial stiffness and moment capacity of the FE model is well predicted by verification with previous experimental testing. The effect of plate thickness gives significant change of the initial stiffness, whilst the higher strength end plate will be more pronounced on the moment capacity of the connection. The high strength end plate gives a significant proportion of maximum stress distribution. Thick high strength endplate connections provide additional rotational stiffness and moment capacity but the rotation capacity may be compromised through bolt failure. Such a failure mode is not acceptable for semi-rigid frame design because a large rotation capacity is required to allow moment redistribution to occur effectively. Thin low strength endplates provide enough deformation capacity to allow semi rigid connection design but yielding of the endplate may produce excessive deflection. Higher strength end plates may delay the end plate yielding and excessive deflection. Significant response from column stiffener gives large increases in the resistance and stiffness of beam-to-column connections through composite action. A simplified finite element approach shows reasonable for use in design semi-continuous composite portal frame with less computational effort.

1

Xiao Y., Choo B.S., Nethercot D.A., "Composite Connections in Steel and Concrete. Part 1Experimental Behaviour of Composite Beam-column Connections", Journal of Constructional Steel Research, 31(l), 3-30, 1994. doi:10.1016/0143-974X(94)90021-3

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £120 +P&P)