HEAVY TIMBER 



An investigation conducted by J. Norman Jensen, Archi- 

 tectural Engineer, Chicago, showed that the range of costs in 

 the three types of construction is so great that no generalization 

 can be made. By comparing the costs of a large number of 

 different types of construction the following conclusions were 

 reached : 



"With column spacing not exceeding 16 feet, mill construction buildings 

 designed for 100 pounds per square foot live load cost 20% less than con- 

 crete buildings; for 150 pounds per square foot live load,, 15% less, and 

 for 200 pounds per square foot live load, about 10% less. When the live 

 load was 350 pounds per square foot or over, a concrete building was the 

 cheaper." 



This investigation showed also that when the column spac- 

 ing in any building is greater than 16 feet, the relative economy 

 of mill construction disappeared. It has been found, however, 

 that a column spacing of 16 feet is ample for the majority of 

 buildings devoted to manufacturing or other mercantile busi- 

 nesses. For most light manufacturing buildings a live load of 

 100 Ibs. per square foot is sufficient, and for a large percent of 

 the buildings used for storage purposes, 200 Ibs. per square 

 foot is all that will ever be placed on the floors. 



An investigation in regard to the cost of insurance on mill 

 construction, steel and concrete buildings showed that in ordi- 

 nary lines of business the rate of insurance on a sprinklered mill 

 construction building and contents runs about 25 cents per 

 $100.00, while the rate on a concrete building and contents 

 unsprinklered runs about 45c. The rate on both types of con- 

 struction sprinklered is about the same, but the cost of install- 

 ing the sprinkler system in the concrete building may make the 

 total cost higher in comparison with a mill construction build- 

 ing. 



The unit cost of a building varies considerably with the 

 height of the structure. In connection with this point the fol- 

 lowing extracts from "Mill Buildings" by H. G. Tyrrell is of 

 interest : 



"Mill construction buildings of one and two stories cost more than 

 buildings of three to five stories, the last being about 15% less per square foot 

 of gross floor area than when all floor space is on the ground. For light 

 products, it is, therefore, economical to make manufacturing buildings not 

 less than three stories in height, for not only is the building itself less ex- 

 pensive, but it also occupies smaller ground space. The only possible reason 

 that might cause the owner of a building for light manufacturing purposes 

 to select one floor in preference to three or more would be the relative con- 



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