Structural Engineering & Statics
where the load goes
Concept

Concrete strength — where it appears

The compressive strength of a concrete, measured on a cube or a cylinder and used as the reference for nearly every other property. Its tensile strength is about a tenth of it and is rarely relied on, which is what makes reinforcement necessary.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

1200 kN214 kN of tiestruts at 20°0.5 huniform from here onGuyon: 0.25 P (1 − a/h) = 214 kN — the same number, from the same lever armbearing 20.0 N/mm² · once spread 5.7 N/mm²

The force that splits what it pushes on

A prestressing tendon delivers its whole force through a plate a fraction of the section deep. One depth further along the stress is uniform, and the spreading in between requires a transverse tension nobody applied — the force that splits end blocks, and the only number in the design that no equilibrium equation on the member can see.

internal-forces · anchorage zone 10321003161000316201234size (mm, logarithmic)nominal strength (N/mm²)the specimen: 3.10the structure: 1.14the plastic limitfracture mechanicsthe test overestimates by 2.71× · D₀ = 120 mm

The bigger one is the weaker one

Two geometrically similar beams of the same concrete should fail at the same nominal stress, because a strength is supposed to be a material property. They do not. The large one fails at less, and the reason is that a crack releases energy in proportion to a volume and consumes it in proportion to an area.

materials · size effect

Named alongside it

The objects these essays reach for when they reach for this one.

Anchorage zoneBearing stressBrittle failureBurstingCharacteristic lengthCrackD regionEquilibriumFlawFracture energyFracture mechanicsFree body

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