CONCRETE BUILDINGS 269 



low by inserting wooden fillers, which were afterwards removed. The 

 walls of the four story portion are 16 inches in extreme thickness up to 

 the third floor, and are 15 inches above that point. The hollow walls 

 have 3 to 4 inches of concrete on each side of the air space. Both the 

 walls and the columns were bonded by vertical bars of twisted steel y^- 

 inch square, extending through them continuously from top to bottom, 

 and similar rods were carried through the buildings from side to side 

 transverse to the beams imbedded in the different floors about 12 feet 

 apart so as to provide a certain transmission of the strain across the 

 building and assure the resistance of the structure as a whole under the 

 action of eccentric loads and pressures. 



"At about every 25 feet in the length of the walls a vertical space 

 of y% of an inch was made, extending from top to bottom and separat- 

 ing the wall into distinct sections. At each of these joints a twisted 

 24 -inch rod was imbedded from top to bottom on each side of the space. 

 Similar rods were also placed at the corners of the building. Where 

 the vertical shrinkage joints occur in the outside walls the continuity 

 of the structure is preserved by carrying through them horizontal lon- 

 gitudinal pieces of twisted ^4 -inch square rods about 2 teet long and 

 set about 2 feet apart throughout the height of the wall. 



"The columns were built in 1 6- foot sections, each section being one 

 story in height, and were constructed by ramming the concrete inside 

 of forms. The vertical boards composing these forms were made in 

 short lengths, breaking joints over the cross pieces, and were placed 

 in position as the concrete was placed in position. The forms were al- 

 lowed to stand until required for another story, often remaining in po- 

 sition for several weeks, although it was considered that the concrete 

 was strong enough to permit their removal when 48 hours old. The 

 walls were laid up between vertical surfaces of plain i^-inch plank, 

 laid horizontally and secured by tie bolts running through the molds. 

 The wall was built up in sections about four feet in height and 

 the concrete was laid in continuous 6-inch layers, extending en- 

 tirely around the circumference of the wall, and was thoroughly 

 rammed as deposited. After the concrete had set sufficiently, the bolts 

 were loosened and the boards forming the sides of the mold were pulled 

 tip and set in position for building another zone of wall. About 35 

 men were at work building the walls and constructed an average of 

 2000 square feet a day. 



