Bearing-strength of high strength steel plates in two-bolt connections

Abstract

This paper presents an experimental and numerical study on the bearing behavior of two-bolt connections arranged in the direction perpendicular to load between high-strength steel members. A series of 36 connections are fabricated from steels with nominal yield strength of 550 MPa, 690 MPa and 890 MPa and tested to failure in double shear. The effect of steel grades, end distance, edge distance and bolt spacing on the failure mode, bearing resistance and deformation capacity are investigated with the supplementary data from the validated numerical model. To explain the reduced bearing resistance compared to tearout failure, the mechanism of splitting failure in two-bolt connections is analyzed with the assistance of numerical simulation. The boundaries to identify tearout failure, splitting failure and mixed failure with the combined features of necking and tearout are derived. A formula to predict the ultimate resistance of mixed failure is proposed. To achieve an optimum use of high strength materials, an optimal range of edge distance to bolt spacing distance ratio is suggested based on the parametric analysis. Comparison with test results show that Eurocode3 method can be extended to bolted connections between high strength steel members with considerable margin of safety.