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Jonathan Ochshorn's Structural Elements for Architects and Builders, Third Edition
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Chapter 5 — Reinforced concrete: Tension elements

Concrete, having very little tensile stress, is ordinarily not used for tension elements. Where it is used, its strength in tension can be taken as approximately 10% of its compressive strength, or 0.1fc'. The cylinder strength of concrete, fc', is the ultimate (highest) compressive stress reached by a 4 in. 8 in. or 6 in. 12 in. cylinder of concrete after 28 days of curing. Reinforced concrete, consisting of steel bars imbedded within a concrete element, would not normally be a good choice for a pure tension element, since the steel reinforcement would be doing all the work. In this case, one might wonder what would justify the added expense of casting concrete around the steel. In fact, two justifications are possible: first, in a reinforced concrete building consisting largely of compressive and bending elements, the use of reinforced concrete for occasional tension elements would allow a similar mode of expression and of detailing throughout the building; second, where the steel in tension requires fireproofing, the use of reinforced concrete in tension (where the concrete cover provides the fireproofing) might prove advantageous, compared to other solutions.