FIRE-PROOF BUILDING CONSTRUCTION. 



617 



half inches. It will he observed that for the same reason as in beam 

 construction, and as before explained, the iron rods for re-enforcing 

 were placed near the bottom of the work, so as to resist the tensional 

 stresses due to the load, while that due to compression in the upper 



Fig. 1 represents a Ke-enforced Beam of Beton supporting a Section of the Floor: a a a, 

 ^-inch iron rods ; b, same sized rods running at right angles with a a a; c, lateral openings 

 through the beams for the circulation of heated air ; d d, flanges supporting ceilings ; e e, re- 

 enforcing beam of wrought-iron. 



portion would be sustained by the beton alone. In this manner, and 

 by this process, over thirteen thousand square feet of flooring and 

 roofing were constructed in the building. 



The only test of any consequence upon the combined strength of 

 the floors and beams together was made on a section of the widest 

 floor in the house, where the beams are eighteen feet span and six feet 

 between centers. Casks of plaster were placed upon the floor over the 

 beam, forming a triangular load of thirty tons, which was sustained 

 without any injury to the floor, or measurable permanent deflection. 

 The dimensions of the beam that sustained this load were, seven by 

 sixteen inches, and eighteen feet span, re-enforced in its lower portion 

 with a seven-inch I-beam, weighing fifty-five pounds to the yard. 



This test indicates that in addition to its admitted fire-resisting 

 qualities, the re-enforced system of construction challenges comparison 

 with other methods of building in matters of strength and of cost, 

 whether for buildings requiring long or short floor-spans. 



