Response of friction joints under different velocity rates

The studies related to the behaviour of steel connections subjected to extreme conditions originated from impact loads have increased in the last few years. However, there is still no consensus on how exactly the whole connection and its individual components behave when subjected to high strain rates, which is translated by the lack of codified design rules. In order to provide a contribution to increase the knowledge on the behaviour of connections under impact loads, in this paper, the response of an innovative friction connection subjected to both quasi-static and rapidly applied loads is examined. This investigation is performed by means of experimental testing, a numerical investigation and analytical developments. A satisfactory agreement between the numerical simulations and the experimental tests was obtained in terms of global and local behaviour of the connection and of its individual components. Afterwards, using the calibrated numerical model, the effect of several parameters were studied: the bending direction, the ductility of the members and the velocity of the application of the load. Finally, an analytical spring model based on the component method currently codified in Eurocode 3 part 1.8 was also developed. This model showed to be able to predict the connection behaviour when subjected to different velocities by just incorporating the strain rate influence on the individual components of the connection.