Experimental and analytical study of combined bolted-welded lap joints including high-strength steel

Bolting is often combined with welding to supplement the welded joints. However, different opinions are available in literature regarding the combined bolted and welded joint strength. Further, the combined use of bolting and welding in high-strength steel applications has not been extensively studied. In this study, a total of 48 combined bolted-welded lap joints with various test variables including ordinary- and high-strength steel were tested. Depending on the initial installation location of the bolt, there was a difference of by about 100 to 250 kN in strength. When the pre-tensioned bolts were applied, the joint strength increased about 100 kN. The load-deformation relationship of the combined bolted and welded joint was first derived based on deformation compatibility. A new formula that is applicable to both ordinary and high-strength steel was proposed and validated based on the test results. In addition, the effect of the fabrication sequence on the joint strength was also evaluated.