THE EFFECTS OF THE EARTHQUAKE AND FIRE ON 
VARIOUS STRUCTURES AND STRUCTURAL 
MATERIALS. 
By Richard L. Humphrey. 
GENERAL DISCUSSION OF THE EARTHQUAKE CONDITIONS. 
On the 18th of April, 190G, the whole civilized world stood aghast 
at the appalling destruction which visited the city of San Francisco 
and vicinity. Three weeks later, for the purpose of studying the 
effect of the earthquake and fire on structural materials, the writer 
began the investigation herein described, lasting six weeks and cov- 
ering the entire affected territory. It would be impossible, however, 
to describe the extent of the damage adequately or comprehensively 
in a report of this character. When we consider the terrific destruc- 
tion wrought in the surface of the earth by the first movement or 
" slip,'' which developed structural weaknesses, it is not surprising 
that this movement and the resulting vibrations should prove so 
fatal to the structures of man. 
In the fire that followed hundreds of thousands of people were 
rendered homeless and dependent on public bounty for shelter and 
the necessities of life. This phase of the disaster appealed to popular 
sympathy and drew spontaneously from all parts of the country 
contributions of food, clothing, household furnishings, and money for 
the relief of the destitute. 
To the user of the materials of building construction the study of 
the behavior and relative efficiency of the various classes of such 
materials under the unusual and rigorous conditions imposed by the 
earthquake and fire is most interesting and instructive. The test was 
one of such violence that only structures of first-class design and 
materials and honest workmanship could survive. Flimsy and loosely 
built structures collapsed like houses of cards under the terrific 
wrenching and shaking, and many of the structures which withstood 
the earthquake were subjected to a second test in a fire which surpassed 
all the great conflagrations of recent years. Some of these structures 
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