Development of component stiffness equations for bolted connections to RHS columns

This paper presents the derivation and validation of analytical equations for prediction of initial stiffness in bolted endplate connections to RHS columns based on the component method of joint characterisation. Analytical derivation of the equations is presented along with explanation of assumptions and simplifications used to reduce complexity. A comparative study with finite element simulation results shows that the equations for the RHS in transverse tension component can be used for all realistic joint geometries with an error of less than 10%. Validation against experimental results from France et al. (1999) show that when used in conjunction with existing equations given in Eurocode 3 Part 1.8 for other joint components such as endplate and bolts, predictions of joint initial stiffness had an average 9.2% error and a maximum 21.4% error which is acceptable for practical use. This is a significant improvement over existing equations where range of validity is severely limited and there is large error in predictions.

► We give the analytical derivation for equations to define initial stiffness of the RHS in tension component.
► Various simplifications are applied to the equations to make it practical and easy to adopt.
► The new equations are much simpler yet give more accurate results over previous equations.
► The new equations also have an increased range of validity over previous equations.