270 SIDE WALLS AND CONCRETE BUILDINGS 



"The partitions in the building are 2 inches thick and are made of 

 solid concrete reinforced by a framework of twisted % -inch bars about 

 2 feet apart, both vertically and horizontally. The partitions were built 

 in molds, and set so that the face comes exactly even with the edge 

 of a shrinkage joint in the floor, and always set over a floor beam. 



"The concrete was made of Atlas cement and broken basaltic rock, 

 all of which will pass through a 2-inch ring and most of which will 

 pass through a i-inch ring. The unscreened rock was mixed with 

 cement in the following proportions : For foundations, I to 10 ; for the 

 walls, floors and most of the work, i to 6 l / 2 ; for the columns, i to 5 ; 

 and for the lower chords of the floor beams, i to 6, using very fine 

 stone." 



In constructing the Ingalls office building in Cincinnati, Ohio, 

 described in Engineering News, July 30, 1903, and Engineering Record, 

 July 1 8, 1903 the methods used were essentially the same as de- 

 scribed above with a few exceptions which will be noted. 



"The broken stone included the total product of the crusher and was 

 fine enough to pass through a i-inch screen. The concrete was mixed 

 rather wet to insure complete filling of all interstices around the bars. 

 Enough water was used to always give a semi-fluid consistency which 

 allowed puddling rather than ramming. It was made wetter for the 

 columns than for the floors and girders because the bars interferred 

 with the ramming in the molds for the columns. The columns were 

 built in one-story lengths and the concrete was rammed in the molds in 

 layers not more than 12 inches deep. The concrete was dumped from 

 the floor above into the bottom of the mold. The steel rods were 

 placed in position before the concreting was commenced, and were 

 wired in position. A force of 28 men working with hoisting machines 

 and wheelbarrows placed about 100 cubic yards of concrete in a day." 



The present tendency in concrete building construction is toward 

 the use of a concrete made of Portland cement and finely crushed stone, 

 mixed very wet and deposited in the molds practically without ram- 

 ming. The concrete must be rich in cement to make a good wall ur. 

 der these conditions. 



