 It should be 16 inches in diameter for the top 2% feet and 10 inches in diameter at the lower end. Concrete made of good cement, sand, and gravel or broken rock is placed in the lower part of the hole to a depth of 6 inches. A standard tablet station...  Special Publications - Página 351935Visualização integral - Acerca deste livro
 | 1923 - 126 páginas
...When located where traffic passes over it, the top of the mark should be slightly below the surface. The procedure in making the standard concrete mark is as follows : A hole is dug to a depth of 3£ feet or more. It should be 16 inches in diameter for the top 1\ feet, and 10 inches in diameter... | |
 | 1926 - 344 páginas
...If located where traffic passes over it, the top of the mark should be slightly below the surface. soil conditions permit. The tablet should be stamped...concrete mark is as follows : A hole is dug to a depth of 3y2 feet or more. It should be 16 inches in diameter for the upper 2y2 feet and 10 inches in diameter... | |
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