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The specific weight, also known as the unit weight (symbol γ, the Greek letter gamma), is a volume-specific quantity defined as the weight W divided by the volume V of a material: = / Equivalently, it may also be formulated as the product of density, ρ, and gravity acceleration, g: = Its unit of measurement in the International System of Units (SI) is newton per cubic metre (N/m 3), with ...
A w/c ratio higher than 0.60 is not acceptable as fresh concrete becomes "soup" [2] and leads to a higher porosity and to very poor quality hardened concrete as publicly stated by Prof. Gustave Magnel (1889-1955, Ghent University, Belgium) during an official address to American building contractors at the occasion of one of his visits in the ...
Hudson's equation, also known as Hudson formula, is an equation used by coastal engineers to calculate the minimum size of riprap (armourstone) required to provide satisfactory stability characteristics for rubble structures such as breakwaters under attack from storm wave conditions.
For normal weight concrete (defined as concrete with a w c of 150 lb/ft 3 and subtracting 5 lb/ft 3 for steel) E c is permitted to be taken as ′. The publication used by structural bridge engineers is the AASHTO Load and Resistance Factor Design Manual, or "LRFD."
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
For example, in designing a staircase, a dead load factor may be 1.2 times the weight of the structure, and a live load factor may be 1.6 times the maximum expected live load. These two "factored loads" are combined (added) to determine the "required strength" of the staircase.
γ′ is the effective unit weight when saturated or the total unit weight when not fully saturated. B is the width or the diameter of the foundation. φ′ is the effective internal angle of friction. K pγ is obtained graphically. Simplifications have been made to eliminate the need for K pγ. One such was done by Coduto, given below, and it ...
Pervious concrete has a common strength of 600–1,500 pounds per square inch (4.1–10.3 MPa) though strengths up to 4,000 psi (28 MPa) can be reached. There is no standardized test for compressive strength. [15] Acceptance is based on the unit weight of a sample of poured concrete using ASTM standard no. C1688. [16]