152 THE SAN FRANCISCO EARTHQUAKE AND EIRE. 
owner or lessee, to afford more glass or light space, but such design 
has a weakening effect, and should be discouraged. The Marston 
Building, on Kearney street, is an object lesson in this respect. On 
the other hand, the Whittell Building, on Geary street, near Union 
square, is commended for its deep plate girders and heavy steel 
generally. It stood well, and no rivets were sheared. Columns, 
exterior and interior, in steel-frame buildings, should in future be 
put in more liberally on the first and second stories, and the strongest 
joints and connections should be adopted in order to resist the bend- 
ing and shearing. These improvements will greatly stiffen the steel 
frame, and prevent the cracking of the Avails. The Kohl Building, 
thus stiffened by lattice girders on all floors, was uninjured in its 
exterior stonework and brickwork, although built upon the edge of the 
made ground along the old shore line. With such strengthening the 
high steel structures will safely endure an earthquake of even greater 
severity than that of April 18, 1906. This kind of building has 
proved its worth and reliability, and minor improvements, as advo- 
cated, will produce an enduring structure. 
In a fifth class are to be placed, but not as failures, concrete and 
reenforced-concrete structures. These have become popular with a 
large number of designers in San Francisco, on account of the 
strength claimed for them, and on account of the indestructibility, 
facility of construction, and fire and rust protection that their 
materials afford. Unfortunately for San Francisco, there were very 
few structures of concrete or reenf orced concrete in the city at the time 
of her great trial ; but these few behaved well during both the earth- 
quake and the resulting fire. Therefore, although such structures 
are admittedly new and comparatively experimental on the Pacific 
coast, the confidence reposed in them has already led to the designing 
and construction of a number of large buildings of this type for 
public or business purposes. At present the sentiment is to limit 
them to a height of six or eight stories, on account of their experi- 
mental character and because of the fear that greater height would 
permit a reversal of stress, due to earthquake and wuncl force in their 
reen forced girders. It is agreed that the columns should be reen- 
forced with steel and braced together wherever possible; that the 
girders should be similarly, reenf orced for tension and shear, and 
made, so far as practicable, continuous over the columns; and also 
that the joints and connections should be strongly stiffened and the 
curtain walls strengthened by a reenforcement. 
Mill construction with brick will undoubtedly be utilized in many 
buildings for a considerable time to come, but the lesson has been 
taught that the materials used should be first-class pressed brick, well 
wetted, and cement mortar, and that all parts should be thoroughly 
