Timber framing,

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ...The individual boards were sur See 'The Elasticity and Resistance of the Materials of Engineering,' by Wm. H. Burr, 1905 edition, pp. 539-541; 'The Materials of Engineering,' by J. B. Johnson, pp. 682-683; also 'Structural Details,' by H. S. Jacoby, pp. 210 and 217. faced on one side. Fig. 64 shows the columns after failure. The column of Type b was found to be as strong as the single stick. At the ultimate load, however, the individual pieces separated somewhat. The failure in this column was a combination of crushing, resulting from straight compression, and of tension, due to the bending of the individual sticks. The columns of Type c were far deficient in strength as compared to the other types. The ratio of length to least diameter of the individual boards of the c columns was 46, while the corresponding quantity for the a columns was 31. The j-for the solid sticks was 7f. The ultimate strengths of these three types of columns as computed by the formula of the U. S. Department of Agriculture, assuming the ultimate strength of the timber in end-compression to have been 4500 lb. per sq. in., and assuming the sticks to have acted as individual columns, would be as follows: Table XVII Type a Type b Type c L--31 31 46 d Ultimate strength (computed)..29,600 lb. 29,6001b. 21,4001b. Ultimate strength, (actual) 49,000 1b. 50,0001b. 38,000 1b. Efficiency 98% 100% 76% Average of values of line (2) and strength computed as solid sticks 39,900 1b 35,800 1b. While the small number of the tests, and the diminutive size of the specimens does not warrant forming too definite conclusions to be extended to large-size columns, it is evident that the columns of Type b or the 'coverplate' type are much superior in strength to the plain laminated type. This is what might be ...