INTRODUCTION TO TABLES. 



The tables for stone or gravel concrete are based on a unit stress in the steel of 18,500 Ibs. 

 per sq. in., and on the concrete of 750 Ibs. per sq. in. This stress in the steel is taken because it 

 possesses a factor of safety of three on the elastic limit. The stress in the concrete is for good 

 stone concrete of a mixture not weaker than 1:2:5. These stresses are commonly governed by 

 building laws or specifications of engineers. The variation is so great that it would be impossible 

 to give tables to govern all cases. We have on hand, and in preparation, tables governed by other 

 unit stresses to conform with building laws of our large cities. We will be glad to forward these 

 on request. 



The loads given in the tables are the safe live loads in Ibs. per sq. ft. In every case the weight 

 of the slab has been deducted. The weights of slab assumed are as follows: 

 Slab Thickness: 3" 4" 5" 6" 7" 8" 9" 10" 11" 12" 13" 14" 15" 16". 



Weight I stone: 37 50 62 75 87 100 112 125 137 150 162 175 187 200 Ibs. 

 Slab J Cinder: 29 38 48 58 67 77 86 96 105 115 125 134 144 153 Ibs. 



The depth from the bottom of the slab to the center of the steel is assumed as:- 

 For 3-13-075 to 3 6-50 inclusive, %" 

 ." 3-6-55 and 3-6-60 1" 



" 3-6- 75 and 3-6-100 \%" 



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