The most used value in the Building Codes of Baltimore, Boston, Cincinnati, Chicago, District of Columbia, and New York City ─────────────┬────────┬───────────┬───────────┬──────────┬──────┬────── Wood │ │ │ │ │Shear │Shear │ │ │ │ │ With │Across │ │ │Compression│Transverse│Grain,│Grain, │Tension,│Compression│ Across │ Bending, │ lb. │ lb. │lb. sq. │With Grain,│Grain, lb. │ lb. sq. │ sq. │ sq. │ in. │lb. sq. in.│ sq. in. │ in. │ in. │ in. ─────────────┼────────┼───────────┼───────────┼──────────┼──────┼────── Yellow pine │ 1200│ 1000│ 600│ 1200│ 70│ 500 White pine │ 800│ 800│ 400│ 800│ 40│ 250 Spruce and │ │ │ │ │ │ Va. pine. │ 800│ 800│ 400│ 800│ 50│ 320 Oak │ 1000│ 900│ 800│ 1000│ 100│ 600 Hemlock │ 600│ 500│ 500│ 600│ 40│ 275 Chestnut │ 600│ 500│ 1000│ 800│ │ 150 Locust │ │ 1200│ 1000│ 1200│ 100│ 720 ─────────────┴────────┴───────────┴───────────┴──────────┴──────┴────── As published in American Civil Engineers Pocket Book. Assuming 2–inch sheeting, the fiber stress is 1,300 pounds per square inch. This stress is too large. By reducing the ranger spacing slightly the stress can be brought within the required limits. Assuming a ranger spacing of 3 feet 9 inches the depth to the upper ranger is changed to 23 feet and the maximum stress in the 2–inch sheeting becomes 1,140 pounds per square inch, a satisfactory result. The results for the computations for the other ranger spacings are shown in Table 60. The spacing of the rangers at the sheeting junctions is controlled by convenience and is not computed so long as it is obviously safe. 3. _Size of Rangers._—The rangers will be assumed as 16 feet long with two end cross braces and one intermediate cross brace for each ranger. Starting as before at the bottom of the trench. The area of the panel below the ranger and between cross braces is 24 square feet. The average intensity of pressure is 28.25 × 18 = 508.5 pounds per square inch. The load transmitted to the ranger is 6,000 pounds. Similarly the load transmitted to the ranger from the panel above is 6,890 pounds. The total distributed load on the ranger is 12,890 pounds. If _b_ is the vertical dimension of the ranger and _d_ is the horizontal dimension in inches, then from the beam theory, using _f_ as 1,200 pounds per square inch, _bd_^2 = _M_⁄200, in which _M_ is expressed in inch-pounds. The maximum bending moment is