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Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]
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 ...
A standard metric (concrete) block is 190 mm wide, 390 mm long, and 190 mm high, which allows for 10 mm mortar joints in between bricks, giving a standard unit size of 200 mm square by 400 mm long. [3] A standard metric brick is 90 by 57 by 190 mm; with 10 mm of mortar, that produces a standard unit of 100 mm x 200 mm. [3]
The respective tables of data were generally developed by using the more complex transfer function method to determine the various cooling loads for different types of heating. [ 2 ] [ 3 ] The results gained by doing so are then normalized for each type of heat gain used for the tables, CLTD, CLF, and SCL.
S is the slope of the energy line (head loss per length of pipe or h f /L) The equation is similar to the Chézy formula but the exponents have been adjusted to better fit data from typical engineering situations. A result of adjusting the exponents is that the value of C appears more like a constant over a wide range of the other parameters. [8]
ACI Code 7.10.4.2: For cast-in-place construction, size of spirals shall not be less than 3/8 in. diameter. ACI Code 7.10.4.3: Clear spacing between spirals shall not exceed 3 in., nor be less than 1in. Section 10.9.3 adds an additional lower limit to the amount of spiral reinforcement via the volumetric spiral reinforcement ratio ρ s.
Mass concrete is defined by American Concrete Institute Committee 207 as "any volume of concrete with dimensions large enough to require that measures be taken to cope with the generation of heat from the hydration of cement and attendant volume change to minimize cracking."
Deflection (f) in engineering. In structural engineering, deflection is the degree to which a part of a long structural element (such as beam) is deformed laterally (in the direction transverse to its longitudinal axis) under a load. It may be quantified in terms of an angle (angular displacement) or a distance (linear displacement).