GB540018A - Improvements in or relating to lattice girders, framed structures or frameworks built up from metal elements - Google Patents

Abstract

540,018. Lattice girders roof trusses. ADAMS, J. E. March 26, 1940, No. 5463. [Classes 20 (ii) and 20 (iv)] In making light framed structures such as lattice girders and roof trusses the metal elements are assembled in their relative positions extending at each joint into or through a moulding box which is then filled with concrete. The moulds may be left permanently in position or may be removed after the concrete has set. The metal elements may be apertured, bent or otherwise shaped to provide an anchorage within the concrete. The moulds may be of sheet steel or of plastic material and are provided with slots for receiving the metal bars such as 2, 3, 4, Fig. 2, the tops of the slots being closed by a tension band 5 after the bars have been placed in position. When necessary the slots are made deep enough to take several parallel bars, which are separated by spacers. A lattice girder of the form shown in Fig. 6 has its joints J1, J2 made in the manner indicated in Figs. 7, 8, the ties 19 and struts 24 being formed with hooked ends and links 22, 28, 30 being placed around the parts to assist the anchorage. If desired the portions of the boom 18 between the joints may be encased in concrete. In the case of a roof truss of the form shown in Fig. 14, in which the rafter member R consists of a bar R1 encased in concrete, slotted moulds somewhat similar to that in Fig. 2 are employed, and the one at the joint J2 communicates with the shuttering about the bar R1. The invention is applicable also to structures involving threedimensional joints. Specifications 271,909, [Class 34 (i)], and 495,566 are referred to.