Comparative Little need be said of the economy of the reinforced over the non-reinforced type of retaining walls. 



Type: Suffice it to say a total saving of 25 per cent, to 45 per cent, has been reached in railroad and municipal work 



by the adoption of the steel reinforced type. The somewhat technical features entering into the design of 

 the reinforced type of retaining wa'ls, coupled with the lack of standardized designs, has served to retard iti 

 universal adoption. 



Reinforced In standardizing the two common types of reinforced retaining walls, namely, the 'cantilever' and the 



Types: 'counterfort,' this pamphlet, in the accompanying designs and data, will be found to fill a long felt want. 



The quantities of material also included in the tables will facilitate greatly the estimating of costs. The 

 designs herewith submitted will be found to conform with the best standard practice. According to author- 

 ities cantilever types are more economical than the counterfort, up to a heighth of 16 to 20 feet. The 

 quantities given will enable anyone to arrive at the most economical construction for his particular case. 

 An allowance should be made for the increased labor on form work in the counterfort type of retaining walls. 



Foundation : No wall should be built on a foundation of soil of less bearing power than three tons per square foot, 



and wherever possible the wall should be built on rock. If a clay foundation must be resorted to, it is very 

 important that it be kept dry and below the frost line. When troubled with springs or accumulative surface 

 water, provide trenches every ten feet to drain the water from the foundation. Such trenches may be one 

 fopt width and depth, and filled with coarse gravel well compacted and given sufficient slope to insure run off, 

 Baker's Table of safe bearing power of soils gives the following permissible loads: 



Rock equal to best ashlar 



Rock equal to best brick masonry 



Rock equal to poor brick masonry 



Clay dry thick beds 



Clay Moderately dry thick beds 



Clay Soft 



Gravel and coarse sand well cemented 



Sand Compact and well cemented 



Sand Clean and dry 



Quick sand, alluvial soil, etc. 



tons per square feet, 

 25 to 30 

 15 to 20 



5 to 10 



4 to 6 



2 to 4 



1 to 2 

 8 to 10 

 4 to 6 



2 to 4 

 tf to 1 



14(1 



