Characterisation of Long Bolts in Shear

Abstract

This paper presents an experimental investigation of the shear behaviour of long bolts, focusing on the effects of bolt diameter, bolt class, grip length and surface finish. High‐strength steel plates of significant thickness are used for load application, ensuring that bearing deformations at the bolt holes are avoided, and that bolt shear is fully mobilised. Although the bolts are relatively long, an assessment of potential bending under applied load shows its influence on shear resistance to be negligible. This confirms that long bolts behave as bolts rather than pins, and that standard bolt shear resistance formulas remain applicable. Predicting the initial shear stiffness remains challenging. Therefore, the approach defined in EN 1993‐1‐8 is adapted to provide improved estimations. A probabilistic reliability analysis is conducted to evaluate the γM2 factor, supporting robust design recommendations. The research is carried out within the European Connect4C project, which develops demountable, reusable and adjustable joint typologies using long bolts to enable flexible and sustainable structural joints. The results provide quantitative guidance for the design of long bolts and support the development of reliable design procedures for advanced structural systems.