. A manual of the principles and practice of road-making: comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and rail-roads . Fig. 106 Still more economical ofmasonry is a leaning retain-ing wall, in which the backhas a bdtir, which may ad-vantageously be 1 in 6. Inthis case strength requiresthat the perpendicular let fallfrom the centre of gravityof the section upon the base,should fall so far uqthin theinner edge of the base, thatthe stone of the bottom course of the foundation maypresent sufficient surface to bear the pressure upon it.*. * M
. A manual of the principles and practice of road-making: comprising the location, consruction, and improvement of roads (common, macadam, paved, plank, etc.) and rail-roads . Fig. 106 Still more economical ofmasonry is a leaning retain-ing wall, in which the backhas a bdtir, which may ad-vantageously be 1 in 6. Inthis case strength requiresthat the perpendicular let fallfrom the centre of gravityof the section upon the base,should fall so far uqthin theinner edge of the base, thatthe stone of the bottom course of the foundation maypresent sufficient surface to bear the pressure upon it.*. * Mahan, p. 142. 186 THE CONSTRUCTION OF ROADS. The strength of a wall may be still farther increased bylessening its thickness, and employing the difference ofthe amount of masonry in buttresses or counter-forts, at-tached to its back at regular intervals, and firmly banded Fig. 107.
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectrailroa, bookyear1853
