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Reports on Special Researches 



carefully and securely anchored into the brickwork by galvanized-iron anchors. The 

 exterior brick walls to the height of the granite course are 22 inches thick; above the granite 

 course to the roof-level they are 18 inches thick. For the purpose of stiffening the building 

 there are three interior 13-inch brick walls carried continuously from the basement to the 

 attic, two of these being transverse walls, one each about 18 feet from the ends, and the third 

 along the center line between these two transverse walls. All of the partitions in the sub- 

 basement, basement, and first floor are of brick and 13 inches thick, except for a few hollow 

 terra-cotta tile partitions on the first floor. Except for the brick strengthening and corridor 

 walls the partitions on the second floor are all of hollow terra-cotta tile laid in cement mortar. 

 The floor-work throughout the building is of hollow-tile reinforced concrete construc- 

 tion. This form was adopted in preference to structural steel because of its greater economy 

 and the greater solidity and stiffness ensuing from its use. ^^11 cement was tested according 

 to the standard specifications adopted by the American Society for Testing Materials. 



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Fig. 3. Transverse Section and Elevation of Main Building. 



The proportions used for the concrete work were 1 of cement, 2 of sharp, coarse, clean sand, 

 and 3 of clean gravel, with no piece larger than would pass through a 2-inch screen. The 

 structural strength of the floors has been increased by a rather unusual method of con- 

 struction, which involved the immediate laying of the finished cement surface at the same 

 time that the floor itself was cast, thus increasing the structural depth by that of the 

 cement filling. The topping was in proportion of 1 part cement to 2| parts of sand. In the 

 usual construction the cinder filling, upon which the finished surface is made, is placed after 

 the floor is set and thus adds nothing to the structural strength of the floor. The floors 

 in all cases have been built as a part of the brick walls and have been anchored into them. 

 The lintels over all of the openings are reinforced concrete and are cast with the floors. 

 The entire structure is thus practically monolithic and fireproof . Corrugated-iron bars were 

 used for the reinforcement. All floors are cement finished to a smooth surface with trowel 

 except those in the lavatories, where 2-inch white hexagon tile set with close joints and 

 sanitary tile base was used. 



