BEHAVIOR OF INDIVIDUAL STRUCTURES. 79 
think that in one or two other buildings in which there was a general 
collapse of the steel superstructure worse columns than this one could 
have been found under the debris. The debris was not cleared away 
while I was in San Francisco, so I had no opportunity to see the con- 
dition of many columns that had evidently failed. 
The basement of the Aronson Building was divided into several 
rooms by hollow-tile partitions. The room in which the buckled 
column was located had evidently contained an enormous amount of 
paper in some form or other, and the heat generated must have been 
very intense. The fire broke through the hollow-tile partition which 
separated this room from the adjacent one, but there was very little 
that was combustible in the latter, and the column standing there had 
its fireproof covering entirely intact. Examination showed that the 
work in this building was neither better nor worse than the average 
of similar work anywhere else in the San Francisco commercial build- 
ings. A plain and inevitable inference is that wherever such work 
was practically undamaged the fire test was not at all severe. 
In the same part of the basement as that in which the above- 
mentioned column was situated — that is, under the Third street wall 
of the building — there were two columns covered with cinder concrete. 
The concrete covering on one column made a very large and heavy 
pier;, on the other it was about 4 inches thick. It was apparent 
that the heat in this front portion of the room was not quite as 
severe as it Avas farther back, where the buckled column was. Not 
only was there very much less evidence of fire in the way of ashes, 
etc., but the general indications pointed to a considerably lower tem- 
perature — although the heat at this point was very severe, neverthe- 
less. The larger cinder-concrete pier was evidently damaged to 
some extent by the heat. The cement had apparently been dehy- 
drated to a depth of one-fourth to three-eighths of an inch on the 
flat surface, and to a greater depth at the corners. The other pier 
showed more evidence of intense heat, It stood opposite the middle 
of the room, where there seems to have been the greatest accumula- 
tion of combustible matter. When I first saw this column the cinder 
concrete was dead and friable to a depth of nearly an inch. How 
much of this was due to original poor quality and how much to the 
action of the fire was difficult to determine, but fire damage was 
very evident. This pier showed on the surface a number of longitu- 
dinal cracks running from top to bottom, indicating that there had 
been a tendency for the concrete to fail and come off under the ex- 
pansion stresses. At a later inspection a part of the concrete covering 
of this column had been knocked off, arnHt then became apparent that 
the cracks above referred to had extended entirely in to the surface of 
the column itself, and enough heat had got in to partly burn off the 
paint along the inner edges of the cracks. 
