Abstract: An assembly element for steel reinforced truss-type panels is cast as a one piece unit in a mold so constructed that the struts of the element are rigidly secured to the upper and lower chord directly as the result of the casting. For this purpose the mold has a lower bottom cap, an upper top base and laterally movable side wall sections. A pair of lateral side wall sections interconnects a bottom cap portion and a top base portion to form a mold part. Thus, the number of mold parts correspond to the number of struts in the element, whereby the element may be removed from the mold in spite of the fact that the top chord and bottom chord are rigidly interconnected already in the mold.