for the edge space, and two thirds inch between rivets. Proceeding thus, the result compares with the practice of Mr. Fairbairn as follows:—
Diameter of rivet. Distance between rivets. Mr. Fairbairn ⅝ inch, or 0.625 inch, 0.8 Handbook ⅔ inch, or 0.666 inch, 0.8
The difference between the results, or 0.041 inch, less than one sixteenth inch, will be partially absorbed by the remark of Mr. Fairbairn that the area of the rivet should be _nearly_ as much as that of the plate, and partly by the difference in results showing the detrusional force of iron.
238. In experimenting to determine the resistance of rivets, Mr. Fairbairn found that by the common plan of riveting, fig. 117, the strength of plates when whole, single, and double riveted, was as follows, the section of the punched plate being in each case equal to that of the whole one.
Whole plate, 100. Single riveted, 56. Double riveted, 70.
This loss of strength made him fearful of the ability of the tension plates of the Britannia bridge to do their duty; and he was led to adopt what he terms “chain riveting,” which consists in placing the rivets as in fig. 118, or _in the same line of tension_. The strength of plates thus made he considers as great at the joints as elsewhere.
239. As to the diameter of rivets, we have the following results of the practice of the best English engineers.
Thickness of plate, ¼, 5/16, ⅜, 7/16, ½, 9/16, ⅝, 11/16, ¾. Diameter of rivet, ⅝, 6/8, ⅞, 1, 1, 1⅛, 1¼, 1⅜, 1½.
240. As to the distance _in the direction of the force_ from rivet to rivet, also from the first rivet to the plate end, we gather the following from the best executed works in boiler plate. See fig. 118.
The distance at right angles to the force has already been given.
241. If we knew the lateral adhesion of rolled plates, that is, the resistance of the fibres to sliding horizontally past each other; we should determine the distance of rivets in the direction of tension as follows:—
Let _R_, equal the resistance per unit of area for _detrusion_ or shearing, _R′_ the lateral adhesion of rolled plates, and we should have
whence _d_ = (_R_ × _a_)/(2_R′_ × _t_); where _a_ = area of rivet, _d_ = distance, _t_ = plate thickness.
supposing the piece 1, 2, 3, 4, fig. 118, to split out.