An experimental investigation on the net cross-section failure of damaged plates containing holes

In Eurocode 3, a design rule is given for predicting the ultimate resistance of the net cross-section at bolt holes. This is based on the average stress evaluated in the net cross-section, and contains both a reduction factor of 0.9 and a partial factor. According to previous research, this reduction factor makes the design rule over-conservative for uncracked components. There are indications that this conservatism accounts for the possible presence of small cracks at the bolt holes. Very limited experimental research has been conducted on the influence of potential cracks at the bolt hole, particularly at the notch root. This paper presents a few experimental results on the ultimate load of pre-cracked notched plate specimens made of S275JR grade steel. Four pre-cracked specimens, with crack depths ranging from 1 to 7mm, have been tested and their ultimate load has been compared with the one of non-pre-cracked specimens, exhibiting lower ultimate load and ductility as compared to the undamaged specimens. However, despite the significant pre-cracking, the ultimate strength is slightly lower than calculated with the design rule of Eurocode 3, considering mean material properties and excluding the partial factor. Moreover, the pre-cracked specimens have been assessed using a constraint-corrected version of the failure assessment diagram validating its prediction with the experimental results.