HEAD OF DEPARTMENT OF Civil Engineering.
DESIGN OF A STEEL RAILROAD WAREHOUSE
INTRODUCTION
In choosing a thesis subject I have endeavored to select one that would be of practical use to one in the work that is to follow the college training. I have decided to present the design of a steel railroad warehouse at New Orleans for the Illinois Central Railroad as I am greatly interested in railroad work and intend to make that my speciality and because the design of warehouses has so far received only little consideration, but chiefly because a careful study of such a subject will give a knowledge of steel structural work.
PRINCIPLES APPLICABLE IN THE DESIGN OF RAILROAD WAREHOUSES
Nearly all railroad warehouses are of wood, but if a warehouse were to be built today it is certain that, except for small buildings and in localities where timber is exceptionally cheap, a wooden warehouse would not be considered. At present steel seems to be the material which most nearly approaches the ideal for such structures. This use of steel is due to the increase in the cost of timber and to the decrease in the price of structural steel, which now makes it possible to build a much stronger, a better looking, and more economical structure than would have been possible ten years ago.
With a steel structure a settlement of a couple of inches would not in the least impair its efficiency, as the members would adjust themselves by flexure to meet the new condition. This property of a steel structure is of great advantage where the foundations must be located in soil saturated more or less with water, as would be the case near the sea or a large river. Where brick or stonework is built on such foundations, the masonry would be quite likely to crack.
Large freight houses have in the past fifteen years generally been built with a wooden frame covered with sheathing or corrugated iron, and with wooden or combination roof trusses covered with gravel, tin, iron or some form of patent roofing-felt which is supposed to be fireproof. To cheapen the construction, a flat roof is frequently used; but this style of roof is very hard to make absolutely water-tight. Again, where corrugated iron is used as a roof covering the wind has a tendency to drive the rain up under the iron. It is claimed that tin or iron when used on a building near salt water, deteriorate rapidly and that a gravel roof would be much better; but if the iron or tin is kept well painted, there is little danger of its being attacked in that way. When tin or corrugated iron is used as a roof, the trusses may be built much lighter than when gravel is used.
Freight houses are often built very long, for example, the Illinois Central banana sheds at Cairo, Illinois. Here, as at all long warehouses, the length of train standing on the track becomes excessive, and in switching the work of the “banana hands” is often interrupted, while if a train is made up by loading successive cars, they are sometimes detained longer than is advisable. Fifteen hundred feet is probably as long as a warehouse should be. Freight houses should probably not be more than two hundred feet wide, since otherwise freight taken directly from the cars to the vessels must be trucked too far. On the other hand, where package conveyors are used, this would matter little; and the wide warehouse would have greater floor space for the same cost of construction. If a large amount of freight is loaded direct from the cars to the vessels, it may be well to run a track between the freight house and the pier; but at most docks, unless space is very valuable, such freight will be handled at a pier independent of the warehouse.