Cassell's building construction; comprising notes on materials, processes, principles, and practice

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. 1913 Excerpt: ...plates must be joined in order to obtain shear stress, and the shear stress is that which causes the pressure on the bearing area, so that with a lap joint of two J-in. plates with f-in. rivets, the bearing area of each rivet will be f x J = "375 sq. in. With regard to the crushing action in the hole, Prof. Unwin says, "The value of the crushing stress which produces injury to the tenacity or shearing resistance of the joint is very uncertain. In the case of steel joints there is no indication of injury with crushing pressures of 50 tons per square inch. With the ordinary proportion of rivets, the crushing action need in no case be considered in single shear joints, and only in double shear joints when the plates are less than in. thick." The ultimate bearing pressure iper square inch that will crush material may be taken as: single shear, iron 30 tons, steel 40 tons; double shear, iron 40 tons, steel 50 tons. The working pressure on the bearing area of rivets, bolts, and pins should not exceed 7 tons per square inch in iron, and 10 tons in steel; but unless there is any special reason Fig. 1136.--T-Iron Flange bolted to Double-Channel Vertical and Flat Bars. double-channel vertical and also to two flat tension bars, by means of two tV-in. plates and ten g-in. bolts, two to each of the flat bars. This joint was asked for in an examination question, but is a most unusual one, and rivets would invariably be used in preference to bolts. Making Rivet Holes in Girders. In the construction of steel girders the rivet holes may be punched and afterwards drilled out J in. larger, or may be drilled the full size without any punching, but must not under any circumstances be punched the full size, as the metal will then be starred round the hole and seri...