Concrete Design - History

[2457F]

Looking for some history to the development of reinforced concrete design. For example, where did "jd" come from. How was it determined that "d" needed to be multiplied by "j" which is some fraction of the effective depth. Why was the letter "j" chosen? Are there any good publications out there that describes in detail how all this came about?

 

[robyengIT]

full bibliography available early '900. You can find many of them in

http://www.archive.org

(free download)

https://mega.nz/#!0E0GxaxY!BNWr_t6xzw4rNP7mjm8zF3k8ikBgIXHS2vRC52-AoY0

 

[JLNJ]

"j" simply comes from the determination of the neutral axis and the resultant of a triangular stress distribution therefrom. All you need is the ratio of the concrete to steel stiffness.

I don't know why it's called "j". Maybe "a" through "h" were taken because they were commonly used descriptors for concrete items (length, width, height, depth, thickness, stem width, etc.) "i" was skipped, and "k" and "j" were next.

 

[JAE]

Here's a couple of OLD books:

From 1945 (see page 163 for jd mention:

https://archive.org/details/ConcreteDesignAndConstruction

and one from 1936 (see page 16):

https://archive.org/details/SimplifiedDesignOfConcreteFloorSystemsWithDesignTables

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[robyengIT]

probably you should check in some books dated end of '800 or early '900 (when the theory was not completely fixed and many lab experiments were under investigation)

 

[2457F]

Thank you everyone for your posts. It has been helpful.