C02TSTEUCTI0N" AND FIRE PROTECTION OF COTTON WAREHOUSES. 33 



The various types of reinforced concrete floor and -roof con- 

 struction suitable for tlie warehouse may be considered as the flat 

 slab, consisting of a thick slab supported by columns having large 

 flaring heads, or capitals; the beam system, consisting of beams at 

 intervals supporting relatively thin slabs of concrete between; and 

 a combination of concrete beams and hollow tile in which the slab 

 between main beams is really composed of a series of concrete beams, 

 or joists, separated by a row of hollow clay tile. 



The flat-slab system of construction is shown by Plate XVI, figure 

 2. The exact size and shape of the head of the columns vary with 

 different designs and conditions. The flat ceiling shows freedoon; 

 from obstructing beams. This permits a minimum height of story, 

 the placing of sprinkler piping close to the ceiling, the most even 

 distribution of light and, in case of fire, the most effective use of 

 water from hose streams. The details of this construction as com- 

 pared with the beam system is shown by Plate XVIII, figures 2 and 3. 

 The flat slab designs are patented. The proprietors supply plans 

 for their use and either make a charge for this or require the privi- 

 lege of supplying material for use or actually doing the construc- 

 tion. This type of construction frequently can be used at a ma- 

 terial saving over the ordinary beam designs. Unfortunately, there 

 are some limitations to the economical use of flat slab designs for 

 some cotton warehouses. These systems are the most economical 

 Avhen the floor or roof is continuous, the spacing of columns is nearly 

 uniform in both directions, and the load to be carried is heavy.^ 



^ These facts may be made more clear by reference to the accompanying 

 plans. The design shown by figure 3 having compartments 40 feet wide with a 

 single line of columns dividing the floor slab into spans — or distances between 

 supports — of 20 feet is admirably suited for a flat slab design provided the 

 division wall is made of reinforced concrete properly designed in relation to 

 the floor or is a panel wall consisting of a concrete frame with panels built 

 of brick or concrete such as was described under discussion of division walls. 

 But if the wall is of any other design, such as brickwork, the flat slab system will 

 not be economical from this standpoint. The spacing of columns in this case 

 is 20 feet from the walls and 16 feet apart, which is satisfactory for the beam 

 construction indicated, though fully as economical results for the flat slab 

 systems would be given by increasing the spacing of 16 feet to 20 feet. The 

 spacing of columns shown is especially economical for the beam design in- 

 dicated. This plan shows a story height of about 13 feet, which contem- 

 plates the storing of cotton two bales high on end, which would result in a 

 floor load of about 100 to 150 pounds per square foot. The flat slab design shows 

 up to good advantage for these and heavier loads, the relative economy of the 

 design being increased as the load becomes heavier. Roofs of this latter de- 

 sign may be used to excellent advantage for the compress compartment, such as 

 is shown by figure 5. Here the spacing of columns 2-5 feet apart in both direc- 

 tions, with the smooth and unobstructed ceiling, is very desirable. 

 12a988°— 19— Bull. 801 3 



