282 Wisconsin Academy of Sciences, Arts, and Letters. 



A CHAPTEE ON FOUNDATIONS. 



Bx J. Nader, Civ. Eng., Madison, Wis. 



The subject of this paper is perhaps one of the most dif&cult 

 and uncertain problems which comes within the province of the 

 Civil Engineer. 



In treating on the subject of foundations, I will endeavor to 

 review the whole practical series, from the ordinary foundation 

 daily required and constructed, to such as tax the ingenuity of 

 man and call forth the efforts of the highest quality of genius 

 and talent. 



The earth's surface, consists of all grades of solidity from the 

 rock, to inpalpable mud ; for this reason we have to be governed 

 by circumstance?, and where nature fails us we must supply the 

 want by artifice. 



1st, Beginning with the most stable, the rock, it is only neces- 

 sary to prepare the surface so that it may receive the intended 

 structure and all requirements are satisfied. Cases may, however 

 occur where the rock bed is of such nature that it will disintegrate 

 by the action of the elements, in all such it is simply necessary to 

 excavate beyond the influence and replace the excavation with 

 enduring material. Where the rock is of sufficient strength, the 

 superstructure may receive considerable strength against lateral 

 motion, as in the case of Eddystone and Bell rock lights, England, 

 also Minot's ledge light and others in this country, by bolting the 

 structure securely to the bed rock. 



2d. Next to solid rock is a bed of hard gravel ; this will in 

 nearly all cases resist any amount of pressure that can be brought 

 to bear, provided that in cold climates, the substantial work is 

 carried to a depth beyond the influence of the frost. 



8d. I shall presume to place sand next in order, to gravel, for 

 solidity. In sand, it is only necessary to go beyond the frost 

 line and to guard against lateral motion ; in every other respect 

 it will support weight equal to rock itself. 'i 



