Comparative numerical investigations into the determination of slip factors according to the EN 1090‐2 and RCSC

Abstract

Slip-resistant connections are used in bolted connections when deformations in the connections have to be for sure avoided either for serviceability or ultimate limit state reasons. On European level EN 1090-2 and on North American level the "Specification for Structural Joints Using High-Strength Bolts" by RCSC (2014) specify slip factors for often used surface conditions for carbon steel. For deviating conditions, slip factors can be determined experimentally according to the specified test procedures. However, not only the test procedure but also the test specimen geometry, clamping length, preload level etc. vary between both standards/guidelines. Generally, the resistance to slip in a slip-resistant connection mainly depends on the condition of the faying surfaces and the preload level in the bolts but the variation of other key parameters may also result into different slip factors for the same surface treatment. For this reason, in a first step, comparative numerical investigations have been carried out for the test procedures specified in EN 1090-2 and RCSC. The numerical models have been developed and calibrated on the basis of experimental tests carried out at the Institute for Metal and Lightweight Structures. Based on the calibrated numerical models, a parametric study has been conducted in order to prove the comparability of both test procedures and their resulting slip-factors. In a second, future step, comparative experimental investigations will be carried out for both test procedures. In the frame of this contribution, the first numerical results will be presented.