in a state in which they are inclined tilted in opposite directions in relation to the horizontal about an imaginary inclination axis 24 in each case the two inclination axes 24 run parallel to one another and perpendicularly to the longitudinal direction 8 here in fig1 perpendicularly to the image plane and through the axis of symmetry of the beam profile each of the two central segment head plates 18 assumes an angle of inclination u03b1 of 45 u00b0 in relation to the horizontal and thus also in relation to the vertical or expressed in more general terms in relation to a plane normal to the longitudinal direction 8 as a result of being inclined in opposite directions in the section view according to fig1 the two central segment head plates 18 would form a v lying on its side if they were extended appropriately to the left the outer segment head plates 20 are inclined in a coordinated complementary manner for this purpose the beam elements 16 of the three segments 10 12 14 are cut in an appropriately inclined manner in a manner similar to miter cut corner connections at the end connections and the head plates 18 20 are welded onto the end edges of the beam elements 16 accordingly in fig1 the central segment 10 has the outline of an isosceles symmetrical trapezoid the head plates 18 20 which are located opposite one another in the respective head plate joint 22 are connected on a permanent basis by screw connection for this purpose the.