Hybrid grouted joints: Load bearing and failure behaviour under static, axial loading

Abstract

The hybrid grout joint is a new type of joint to structurally connect circular hollow sections (CHS). It combines the two joining processes adhesive bonding and mineral grouting. While the adhesive bonding process is performed under controlled environmental conditions, the grouting is conducted on-site. Of particular interest is its ability to compensate tolerances, which makes it very interesting in various areas of steel construction. In the present paper, the influence of different factors on the load-bearing behaviour under quasi-static, axial loading is investigated. In general, the connection is characterised by high stiffness and load-bearing capacity. With increasing overlap length, the capacity increases, although because of the stress concentrations average shear strength decreases. The radial stiffness of the adherends is identified as a second considerable influence factor for the load-bearing capacity. With increasing radial stiffness (decreasing diameter/thickness ratio), bond strength increases. The load capacity under compression is about 10% lower than under tension. Two investigated imperfections, misalignment and eccentricity, exerted no negative influence on the load-bearing behaviour. While changing the adhesive influences the load-bearing behaviour, a change of grout has negligible influence. Additional tests on hybrid grouted joints with reinforced grout layer show, that reinforcing the grout layer is not necessary.