Abstract: A lattice girder generally including a top rail, a bottom rail, vertical end posts and slanted crossbeams, wherein all of the members consist of uniform hollow sections that may be fitted into one another and thereby rigidly interconnected. The girder rail consists of two half-sections (18,19) internally provided with longitudinal flanges (20, 21) having transverse serrations so that the two half-sections may be permanently secured to one another by pressing them together with the serrations in mutual engagement. The end of a slanted crossbeam (24) having notches (at 25 and 26) is inserted into openings (22,23) in the half-sections to lock and engage the rail. Weldless lattice girders may thus be produced, in particular for forming a walkway guardrail.