Canadian engineer . ssion isdependent upon the modulus of elasticity of the timber andthe steel in the nails. failure of the timbers, this was in agreement with the obser-vations. In experiments Nos. 6 and 7 the nailing was as before,but the timbers were of an intermediate size 4 in. x 8 occurred at about the same average load per nail asin experiments Nos. i, 2 and 3, but while in No. 6 failureoccurred by breaking of the timbers, in No. 7 the failurewas due to bending and drawing of the nails. The propor-tioning of nails to timber was, therefore, about correct. Omitting experiment
Canadian engineer . ssion isdependent upon the modulus of elasticity of the timber andthe steel in the nails. failure of the timbers, this was in agreement with the obser-vations. In experiments Nos. 6 and 7 the nailing was as before,but the timbers were of an intermediate size 4 in. x 8 occurred at about the same average load per nail asin experiments Nos. i, 2 and 3, but while in No. 6 failureoccurred by breaking of the timbers, in No. 7 the failurewas due to bending and drawing of the nails. The propor-tioning of nails to timber was, therefore, about correct. Omitting experiment No. 8 and averaging the values ofa Q-in. spike as found in the remaining four experimentswhere failure took place by drawing of the spikes and using griip in inches number of nails as found by equation, Ys total length—const., we get 1570 as ultimate load value in shear of 9 in pine, as against a theoretical value of 1540 greatest divergence of a single experiment from theaverage was 60 SKETCH 3 Notes on Results of Experiment. To design a well proportioned joint it was necessary firstto ascertain the laws governing the holding power of a q-inch spike in cases where the failure took place by drawingof the spikes, that is, to find the value of one spike, andsecond to find the limiting number of spikes which woulddevelop their full load (that is, would not cause failure bysplitting) in a joint made up of 4 in. x 8 in. pieces. The 8in. dimension -was fixed by the load on the side of the flumeunder consideration. Specimens Nos. i, 2, and 3 were made with 4 in. x 10in. used as cross pieces (failure by cracking would occur inthe cross pieces if at all) and with two, three and four nailsper piece respectively. In every case the failure of thejoint took place in the nails, and since the results were quiteunfform (1580, 1590, 1570 average per nail respectively) itmay reasonably be concluded that these values would holdfor 9-in. spikes in pine regardless of
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