On the distribution of the energy stored in reinforced concrete beams and column-supported, flat-slab floors
✍ Scribed by Henry T. Eddy
- Publisher
- Elsevier Science
- Year
- 1918
- Tongue
- English
- Weight
- 451 KB
- Volume
- 186
- Category
- Article
- ISSN
- 0016-0032
No coin nor oath required. For personal study only.
✦ Synopsis
I. SINCE the most accurate and complete test data available respecting reinforced concrete beams is found in Technological Paper No. 2, U. S. Bureau of Standards, I in which are given details of tests upon 333 o~ these beams, for convenience of comparison the developments in this paper will deal with beams reinforced and loaded in the same manner as those in this Paper No. 2.
The beams in Paper No. 2 had a span between supports of l = 12 ft., a width of b = 8 in., a total depth of I I in., and a depth to the centre of the bottom layer of steel of d = IO in., a total actual length of I 3 ft., a uniform reinforcement from end to end, and equal concentrated loads = ~ /IV placed at each of the onethird points of the span. T~he reinforcement consisted of halfinch round rods from two to eight in number, of mild steel with an elastic limit between 33,000 and 41,ooo lbs., a yield point between 35,000 and 43,000 Ibs., and an ultimate strength between 52,000 and 64,0o0 Ibs.
The reader is referred to the paper itself for the numerical results .of the tests, except so far as herein quoted, as well as for the details of the construction of the beams.
- Let M designate the bending moment, I the moment of inertia, R the radius of curvature, k the proportional depth of the neutral axis, and D the deflection at mid span. None of these quantities except D vary in value between the one-third points, and they also have nearly the same values in the end thirds for some distance from the one-third points toward the ends. Especially is this ~he case with I and k, as may be known from Figs. 22 to 3 o, inclusive of Paper No. 2, which reveal the fact that the cracking of the concrete by t~nsion extends throughout almost *By Humphrey and Losse, Government Printing Office, Washington, x9x2. 439