The object of the test was to ascertain the result of applying to these floors, first, a temperature of about 1,700° F. during four hours, a load of 150 lbs. per square foot being upon them; and second, a stream of water forced upon them while still at about the temperature above stated. A column was placed in the chamber roofed by the rock concrete, and it was tested the same way.
The fuel used was seasoned pine wood, and the stoking was looked after by a man experienced in a pottery; hence a very even fire was maintained, except at first, on the cinder concrete side, where the blaze began in one corner and spread rather slowly for some time. The water was supplied from a pump at which 00 lbs. pressure was maintained, and was delivered through 200 feet of new cotton hose and a nozzle. Each side was drenched with water while at full temperature, apparently; and the water was thrown as uni formly as possible over the surface to be tested, for the required time. The floors were then flooded on top, and again treated underneath.
Inasmuch as the floors and the column were the only parts sub mitted for tests, the slight cracking and pitting of the walls and partition need not be detailed.
The column was practically intact, except that a few small pieces of the concrete were washed out where struck by the stream at close range. The metal, however, remained completely covered. On the rock concrete side, the beams showed naked metal up to within about 7 inches of the ends on one beam, and about 2 feet from the ends on the other beam. The reinforcing bars were de
nuded over an area of about 30 square feet near the center; but no cracks developed, and the water poured on top seemed to come down only through the pipe set in for the pyrometer.
On the cinder concrete side, the beams lost only a little of the edges of the covering, not showing the metal at all. There were no cracks on this side either, and the water came down through the pyrometer tube as on the other side. The metal in the.slab was bared over an area of about 24 square feet near the center.
During the firing, both chambers were occasionally examined, and no cracking or flaking-off of the concrete could be detected. Hence the water did all the damage that was apparent at the end.
During the test the floors supported the load they were designed to carry; and on the following day the loads were increased to GOO pounds per square foot.
The following is taken from Professor Van Dyek's report: "The maximum deflection of the stone concrete before the application of water, was 21z, inches; after application of water, 3 inches; with normal temperature and original load, inches; deflection after load of 600 pounds was added, 3i-,1 inches.
"The maximum deflection of the cinder concrete before the application of water, was inches; after application of water, 61 inches; with normal temperature and original load„511 inches; deflection after a load of 600 pounds was added, 6 inches. These measurements were taken at the center of the roof of each charither."