All the floor-beams were the same size, being 10 inches wide and 18 inches in depth below the slab; but the amount of reinforce ment was varied. In the cross-beams between the columns, the reinforcement consisted of 5 twisted bars 1 inch square; but 6 bars 1 inch square were required for the cross-beams between the longi tudinal beams, as the span was 4 to 5 feet longer for most of the floors. The detail of the beams between the columns is shown in Fig. 196a. The longitudinal beams between the columns were reinforced with 4 twisted bars 1 inch square, the details of which are given in Fig. 196b. The stirrups for all the beams were made of round steel bars. The beams were connected by a 5-inch slab reinforced with 2-inch square bars spaced 5 inches.
383. Erben=liarding Company Building. The exterior and interior of a factory building, designed and constructed by Wm. Steele Sons Company for the Erben-Harding Company, Phila delphia, are shown in Figs. 197 and 198. This building is 100 feet by 153 feet, and was constructed structurally of reinforced concrete, except that structural steel was used in the columns. The floors and columns were designed to support safely a live load of 120 pounds per square foot.
The floor-panels were about 12 feet by 25 feet, the girders having a span of about 12 feet, and the beams a span of 25 feet. One in termediate beam was placed in each panel, as shown in the interior view. The girders were 12 inches wide and 20 inches deep below the slab, mid were reinforced with 4 bars inches in diameter. The beams were 12 by 1S-inch, and were reinforced with 4 bars 11 inches in diameter. The floor slab was 4 inches thick, and was reinforced with 3-inch mesh, No. 10 gauge, expanded metal.
The columns were all 18 by 1S-inch; but the structural steel (4 angles arranged as shown in Fig. 199) in the columns was de signed to support the entire load on the columns. Four --inch bars were placed in the columns and wrapped with expanded metal. The exterior columns were exposed to view on both the exterior and the_interior of the building.
The entire width between the wall columns was filled by triple win dows. The wall beams were constructed flush with the exterior surface of the wall columns, as shown in Fig. 197. The space between the bottom of the win dows and the wall beams was filled with white brick.
The two fire towers located a t the cor ners of the building were also constructed of white brick.
The floor finish of this building is somewhat unusual. Sills 2 by
4 inches were laid on the structural floor-slab of concrete, and the space between these sills was filled with cinder concrete. On these sills was laid a covering of 24nel' tongued-and-grooved plank; and on these planks was laid a floor of ;-inch maple, the la tter being laid perpendicular to the 2-inch plank.
384. Swarthmore Shop Building. In constructing the new shop building at Swarthmore College, Swarthmore, Pennsylvania, in 1906, concrete blocks were used for the side walls, and the floors were constructed of reinforced concrete. This building is 49 feet 8 inches by 112 feet, and is 3 stories high. The floors were designed to carry a live load of 150 pounds per square foot. A factor of safety of 4 was used in all the reinforced-concrete construction.
The columns are located as shown in Fig. 200. The span of the girders is 20 feet, except for the three middle bays, in which the span is only 10 feet. The 20-foot girders are 14 inches wide, and the depth below the slab is 23 inches. The reinforcement consists of S bars inch square. The details of these girders are given in Fig. 201.
The beams are spaced 5 feet center to center. The span of these beams is about 16 feet, the width S inches, and the depth 12 inches below the slab; and the reinforcement consists of 5 bars a inch square.
The slab is 4 inches thick, including the top coat of 1 inch, which was composed of 1 part Portland cement and 1 part sand. This finishing coat was put on before the other concrete had set, and was figured as part of the structural slab. The slab reinforcement consisted of i-inch bars spaced 4 inches on centers, and -1-inch bars spaced 24 inches at right angles to the bars spaced 4 inches. The columns ranged in size from 10 by 10-inch to 18 by 1S-inch, and were forced by placing a bar in each corner of the column, which bars are tied together by inch bars spaced 12 inches. The amount of this steel was about one per cent of the total area of the column.
Fig. 202 shows the plans of the stairway. The lintels were moulded on the ground, and placed when the side walls had been built to the proper height for the lintels to be placed. The size of the lintels was varied on the different floors to conform with the architec tural features of the building. The width of the lintels was made the same as the thickness of the walls, and therefore both sides of the lintels were exposed to view. The lintels were reinforced with 3 bars I- inch square.