Adhesively bonded steel tubes - Part II: Numerical modelling and strength prediction

Capacity prediction of adhesively bonded joints remains challenging; this is particularly true for tubular joints composed of circular hollow sections used in civil engineering. This paper extends its companion paper, which presented experimental results of a large research campaign on full-scale tubular joints, with the aim to develop a dimensioning method. Firstly, experiments were designed to quantify the strength of the adhesive-steel connection; the results thereof were cast into the formulation of an adequate failure criterion, for each of the adhesives considered. Secondly, numerical models of all investigated joint configurations were established, from which the stress-state inside the bonded connection could be determined. A series of analyses clearly showed that stress magnitude and joint capacity did not correlate, thus indicating that a direct stress based methodology is destined to fail. Accordingly, a probabilistic method that is based on the concept of size effects was developed, and implemented. It allowed not only determining average values for joint capacities, but also estimated the expected experimental scattering thereof. The validity of the approach was tested by successfully comparing experimental and computed joint capacities.