Experimental test results vs. analytical prediction of welded joint strength in hybrid steel trussed concrete beams (HSTCBs)

Results of experimental tests on welded joints of steel truss for encased composite steel-concrete beams are presented. The steel truss is constituted by a steel plate acting as the bottom chord, made of S355 structural steel, coupled with steel rebars constituting the upper chord, and steel inclined web rebars (V-reverse) welded to the two chord elements, both of them of steel B450 C. Butt welded joints of web bar to bottom steel plate and fillet welding joint of inclined web bars to top chord bars were tested. For prediction of strength of fillet welding joints two analytical expressions are derived: the first is based on a local failure criterion and the second on a limit domain of the welding section. Comparison with experimental data proves the equivalence and reliability of the proposed indications. Guidelines for choosing the effective dimensions of the fillet weld able to ensure a required strength are provided. For validation of the suggested guidelines a high precision digital scanner is used to determine the geometrical characteristics of the fillet weld.