Transactions . course be only approximate, but will show thegeneral law as to the efficiencies of the various forms. It wrasnot considered worth while to take weight of pieces intoaccount. Clarks Beam. No. 51. Built like Fig. 48. Side-struts of whitepine, secured by wire nails. Broke at 12,800 pounds. No. 52. Exactly similar to No. 51. Broke at 12,500 pounds. No. 53. Exactly similar to No. 51, except that struts were se-cured by 2-inch wire nails. Broke at 13,840 pounds. No. 54. Exactly similar to No. 53. Broke at 13,200 pounds. No. 55. This beam had two thicknesses of
Transactions . course be only approximate, but will show thegeneral law as to the efficiencies of the various forms. It wrasnot considered worth while to take weight of pieces intoaccount. Clarks Beam. No. 51. Built like Fig. 48. Side-struts of whitepine, secured by wire nails. Broke at 12,800 pounds. No. 52. Exactly similar to No. 51. Broke at 12,500 pounds. No. 53. Exactly similar to No. 51, except that struts were se-cured by 2-inch wire nails. Broke at 13,840 pounds. No. 54. Exactly similar to No. 53. Broke at 13,200 pounds. No. 55. This beam had two thicknesses of white-pine struts on each side, the second layer being placed at rightangles to the first, and the whole secured with wirenails. Broke at 16,670 pounds. 704 THE EFFICIENCY OF BUILT-UP WOODEN BEAMS. Xo. 56. Built like Fig. 48, l>ut the struts were of selectedNorway pine, thick, secured by wire at 11,650 pounds. Xo. 57. Same as Xo. 56, except that struts were of 1-inch. Norway pine, secured by wire nails. Broke at 15,000pounds. Xo. 58. Built like Fig. 49. White-pine struts thick,secured by wire nails; 8 oak keys 1 by 2 inches, and12 6-inch steel spikes. Broke at 16,690 pounds. THE EFFICIENCY OF BUILT-UP WOODEN BEAMS. 795 No. 59. Exactly like No. 58. Broke at 13,200 poundsNo. 60. Exactly like No. 58. Broke at 14,800 poundsNo. 61. Four pieces inches deep, built up as in Fig. Fig. 48.
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
