The site for the warehouse has been taken at New Orleans, Louisiana, on the property of the Illinois Central fronting the gulf known as Stuyvesant Docks. The design, however, is adapted to any sea-board town where a great deal of heavy freight is received from railroads for shipment by water, or vice versa. It might also with a few variations be suitable for an inland town.

The warehouse will be 600 ft. long. This length is chosen because it represents the length of wharf available for that purpose. The width of the building will be 148 ft., of which 20 ft. in the center will be occupied by two tracks spaced fifteen feet center to center, which allows an ample passage-way between the tracks and also between the floor and the track.

Load. The size of warehouse having been decided upon, the next thing is to select the proper floor load to be allowed for. This depends upon the class of freight to be expected and also upon the manner of storing it. Passage-ways will at most times be left in the freight for accessibility, which will make some difference in the loading; but as the passageways are likely to be omitted at some time, the unit load should be on the side of safety and cover all contingencies. A load of 250 lbs per. sq. ft. on both the upper and lower floor has been taken in this design, which it is believed will be ample as iron ore, lead, etc., will not be stored here.

Support of Upper Floor. The columns will be spaced 20 ft. apart in the direction of the length of the building, and 15 ft. in the other direction. The girders will run parallel to the length of the building and therefore the girders will be 20 ft. long and the joists 15. The economic length of the girder is somewhat less than 20 ft. but by this spacing of the columns more clear room will be obtained, which is a thing worthy of some consideration.

Roof Trusses. The vertical load on the roof will be taken as 35 lbs. per. sq. ft. of horizontal projection, of which 20 lbs. is supposed to cover the weight of the roof itself, and 15 a possible load due to wind. The horizontal effect of the wind is taken as 30 lbs. per. sq. ft. of the vertical projection. A design was first made in which it was intended to span 60 ft. with one Fink truss, but this required such heavy construction in the truss members, that the span of the trusses was reduced to 30 ft. and a column was projected up through the second story to carry one end of the trusses.

For an elevation of the trusses see Plate III, page 23. The stresses in the several members of the trusses were found by graphical resolution. In many cases a stress was found smaller than would be safely carried by a 2 × 2–inch angle, but on account of riveting a smaller section could not be used. For details of the trusses see Plate III, page 23.

Purlins. The purlins are spaced 7 ft. apart and have a span of 20 feet. This requires rather a heavy purlin, and on account of the length there will be more or less deflection in it; but this will not be in the least detrimental. Five-inch nine-pound channels will be used, and on these will be bolted the nailing pieces.

Roof Covering. Over the purlins will be laid 1½–inch fine sheathing covered with tin. Tin is used in preference to corrugated iron, as it may be soldered so as to be absolutely water-tight. On the underside of the sheathing will be nailed a layer of asbestos to prevent sparks from the engines below setting fire to the woodwork.

Flooring. The flooring for the upper story will be 3–inch well-seasoned long leaf yellow pine surfaced to a thickness and laid with square joints. The floor can safely carry the required load with a span of 4 feet, and therefore the joists will be spaced 4 feet center to center. The joists will be supported by girders which are in turn supported by the columns. The joists will be 15–inch 42 lb. I beams, and the girders 20–inch 65–lb. I beams.

Columns. Only two columns will be designed: one having only a part of the roof to support, and one that supports this column and the load on the upper floor. The first is designated A on Plate III, page 23, and the second B.

Column A. The load due to the weight of truss, wind and snow is 24000 lbs. A column composed of 4 angles 3½ × 2½ × 3
16–in. and 2 × ½–in. lacing will be used. The cross-section is shown in the figure . The moment of inertia about the axis AB = 20.4 × 4 = 81.6 inches, and the distance C, from the center of gravity of the cross section to the most extreme fibre, = 4. The bending moment, M, caused by the wind on the roof = 1,442,000 inch pounds. Substituting these values in the formula M = SI ÷ C and solving for S, we obtain a value of 7100 lbs. per. sq. in. The stress per. sq. in. due to the weight of the trusses = 3300 lbs. Therefore the total stress = 7100 + 3300 = 10400 lbs. per. sq. in. The allowable stress = 16000 - (45 l
v). l
v = 13.7. Therefore the allowable stress = 11400 lbs. per. sq. in.

Column B. The dead load caused by column A is 12 tons, and the load on the column due to the second floor is 41.5 tons, making a total of 53.5 tons. The length of column is 12 ft. Try a column composed of four 3 × ½ in. Z bars laced. Half of the wind pressure on the windward side above the floor is transmitted by the roof and the lateral bracing to the columns on the leeward side of the building, and half is carried directly by the columns on the windward side. The wind pressure to be resisted by 10 columns = 46 × 30 × 20 = 27,600 lbs. The columns being fixed at the base, the total moment of the wind = 27,600 × 12 × 6 = 1,987,200 in. lbs. and the moment resisted by one column = 198,720 in. lbs. I ÷ C for this column = 35.1. By substitution in the equation M = SI ÷ C, S = 2300 lbs. per sq. in (approx.). The area of the column = 9.31 sq. in.; and the stress in the column due to the dead load = 83000 ÷ 9.31 = 8900 lbs. per. sq. in.

The other columns will be stressed less than this one; but this section will be used throughout for the columns on the lower floor.

Wind Bracing. Only the method of designing member AD (see Plate III, page 23) will be explained. The wind pressure to be transmitted = 4800 lbs. The secant of the angle of inclination = 1.06. Therefore the stress in AD = 4800 × 1.06 = 5100 lbs. A ¾–in. round rod will be used.

In the same way the sizes of the members CE, EF, and FG are determined.

Foundation. The maximum load for the column is about 55 tons. The foundation will be built on piling, as experiments made by F. J. Llewellyn—Engineering News, May 11 1899—show that the safe load for the soil at New Orleans is only about 700 lbs. per. sq. ft. Nine piles will be used in supporting each column. The depth of pile necessary to safely support the load will be found by driving a few trial piles and using what is known as the Engineering News formula (Baker’s Masonry Construction page 245) P' = 2Wh ÷ d + 1, in which P' = the safe load in tons; and d is the penetration in inches under the last blow. W is the weight of the hammer in tons; and h h is the fall in feet. The piles will be of good quality straight-grained white oak, and before being driven, the entire bark will be stripped off. No pile less than 15 in. at the top will be used. The piles will be spaced 3 ft. center to center. A detail drawing of the foundation is shown in Plate III, page 23. The concrete used in the foundation will be composed of 1 part Louisville Natural cement and 4 parts of sandstone broken to pass a 2½–in. ring, the part passing a ½–in. ring being screened out. The concrete is assumed to have a compressive strength of 10 tons per sq. ft., and then the area of the cast iron base to support the column will be 55 ÷ 10 = 5.5 sq. ft. A base 30 inches square will be used.

The first floor will be composed of 6–inches of concrete made as that for the foundation resting directly on the ground. Over this will be spread ½–in. of neat Portland cement to give the floor an even surface.