A stylized, rational criterion for the structural design and installation of reinforced concrete pipe culverts was developed by the Bureau of Public Roads in cooperation with Prof. M. G. Spangler of Iowa State College and the American Concrete Pipe Association and was distributed to the various state highway agencies, April 4, 1957, as Circular Memorandum 22-40.* The criterion was intended to bring together and simplify methods for computing the strengths required for various fill heights and conditions of bedding. The several highway agencies were urged to adopt the criterion for use on all Federal-aid projects and accordingly, the Kentucky Department of Highways issued Amendments No. 15 and No. 16 (Feb. 28, 1958) to its 1956 edition of Standard Specifications for Road and Bridge Construction. Standard Drawings No. 11.22 and No. 11.23 were issued along with these amendments. Amendment No. 15 was later superseded by Amendment No. 15a (Dec., 1961). These amendments and standard drawings were faithfully patterned after the criterion outlined by the Bureau of Public Roads but contained some practical modifications which for the most part were incidental to the transformation of the design criterion into specification style. Class B bedding, with its B1 modification for high fills, was adopted as standard. Each is similar to the same respective designation as described in the Bureau' s Circular Memorandum 22-40. The strengths needed for the respective conditions and heights of fill were resolved from the criterion and were set forth in "Table for Safe Fill Cover Heights and Classes for Reinforced Concrete Circular Pipe" on the Department's Standard Drawing No. 11.23. Installation procedures were diagrammed and outlined on Standard Drawing No. 11.22.

Report Date


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No. 208

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