Frame Analysis Incorporating The Effect Of Lateral Movement In Metal Dowel Fastener Connections

In 10.10 the stiffness of connections at the SLS and the ULS are defined and a method for determining the displacement at the connection when it is subjected to a lateral load is also given.

The displacement effect caused by slip in connections in a structure must be taken into account in any displacement analysis of the structure. Unless the structure is statically determinate, the slip at the connections will also affect the stress distribution around the structure and this must also be taken into account. Further, where the connections have different creep behaviour, from the content of 10.10 it will be understood that as well as having an effect on the displacement behaviour of the structure at the final deformation condition, the stress resultants at the ULS will also be affected and need to be addressed in the analysis.

Where a computer-based frame analysis is to be used, slip behaviour at connections can be included for by introducing a linear elastic spring element at each affected connection with an axial stiffness equal to the lateral stiffness of the connection. Spring elements with rotational stiffness simulating semi-rigid rotational behaviour can also be modelled, and this is discussed in Chapter 12.

In modelling these additional elements care has to be taken to ensure that the stability of the structure is retained, that the shear and flexural properties of the elements properly represent the connection behaviour, and that the size of the elements used will not result in ill-conditioned equations.

Guidance on the loading and stiffness requirements to be used in this type of analysis is given in 2.3.4.1 and 2.3.4.2, respectively.

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