The elasticity and resistance of the materials of engineering . pike, pounds. Mean. 7,283 )7,656 f 7i4 ,472 6,117 I4,589^5,353 5,978 ?6,283 4,4534,4534,3013,380 J4,453 L4,148 P 4,147 300 To pullingspike, pounds. Mean. i:2g[«42o (Split.) 3-34ol3,028 I1:300 3,290 3,493 J ?^M 4,1754,202) ^ ^ ^725U,8775,030 ) 1,968 664 SHEARING BY BOLTS AND KEYS. [Art. 80. very little to the holding power of the spike, and it was desiredto press the spike out again by direct pressure after turning theblock over. . The forces exerted in pulling and driving the spikes wereproduced by a lever. A few tests with
The elasticity and resistance of the materials of engineering . pike, pounds. Mean. 7,283 )7,656 f 7i4 ,472 6,117 I4,589^5,353 5,978 ?6,283 4,4534,4534,3013,380 J4,453 L4,148 P 4,147 300 To pullingspike, pounds. Mean. i:2g[«42o (Split.) 3-34ol3,028 I1:300 3,290 3,493 J ?^M 4,1754,202) ^ ^ ^725U,8775,030 ) 1,968 664 SHEARING BY BOLTS AND KEYS. [Art. 80. very little to the holding power of the spike, and it was desiredto press the spike out again by direct pressure after turning theblock over. . The forces exerted in pulling and driving the spikes wereproduced by a lever. A few tests with a hydraulic pressshowed that the friction of the plunger varied from about 6 to18 per cent. The accompanying table gives the results of the experi-ments. Art. 80.—Shearing Resistance of Timber behind Bolt or Mortise Holes. Col. T. T. S. Laidley, , made some tests during 1881at the United States Arsenal, Watertown, Mass., on the resist-ance offered by timber to the shearing out of bolts or keys,when the force is exerted parallel to the The test specimens are shown in Figs. I and 2. Wrought-iron bolts and square wrought-iron keys were used. All thetimber specimens were six inches wide and two inches diameter of the bolts used (Fig. i) was one inch for all thespecimens. The keys were i x and x asshown in Fig. 2. In all the latter specimens, failure took placein front of the smaller key where the pressure was greatest. In many cases the specimen sheared and split simultane-ously in front of the hole. By putting bolts through thepieces in a direction normal to the force exerted, so as to pre- Art. 81.] BULGING OF PLATES. 665 vent splitting, the resistance was found (in most cases) to beconsiderably, though irregularly increased. KIND OF WOOD. Spruce (bolts). White pine (bolts) Yellow pine (bolts) Yellow pine (square keys). White pine (square keys). Spruce (square keys), CENTRE OFHOLE END OFSPECIMEN. Inches. 11 TOTAL AREAOF
Size: 3329px × 751px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1800, booksubjectbuildingmaterials, bookyear1883
