GB754303A - Improvements in and relating to wooden beam constructions - Google Patents

Abstract

754,303. Girders. BROSENIUS, K. H. Oct. 5, 1954, No. 28625/54. Class 20(4). In wooden beams comprising a web of at least two layers of boards 1, 2,. crossing each other diagonally and flanges each made up of at least two layers of laths 3 ... 6 glued together and nailed to the longitudinal edges of the web on both sides, the diameter of the nails which may be grooved is relatively small and preferably does not exceed 1/30 the nail length, the maximum diameter being e.g. 25-3 in. The glued longitudinal joints e.g. oblique or hooklike, between the boards of each layer of the flanges are so arranged relatively to those in adjoining layers that all are approximately uniformly distributed as are the nails along the length of the flange. The beam end may have vertical strips 7, 8, and the nails 9, 10, securing these and the flange laths to the web are driven in alternately from both sides so as partly to penetrate the further flange or strip. Softer but tougher timber may be used for the web which may be made up of relatively high strength boards where transverse forces are great, e.g. Douglas fir near the beam support and spruce in other parts. Two beams I, II may be connected at an angle to one another in frame or arch constructions &c., a stiff quadrilateral plate S of one beam being bounded by flanges 53, 54, and one or more transverse members 55, 56, extending in the direction of the other beam flanges so as to be embraced by their fork-like extensions 59a, 60a, for assembly at the building site. Flange 54 may be connected by a thick plywood plate to an end strip 61 of beam II. Intermediate laths extending parallel or at angles to the beam flanges but of less strength may be nailed to both sides of the web. A roof girder with a slight pitch comprises similar half beams 71, 74, with the flanges connected by joint pieces 77, 78 and the webs by joint pieces 79.