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Marcus's method is a structural analysis used in the design of reinforced concrete slabs.The method was developed by Henri Marcus and described in 1938 in Die Theorie elastischer Gewebe und ihre Anwendung auf die Berechnung biegsamer Platten. [1]
The Wood–Armer method is a structural analysis method based on finite element analysis used to design the reinforcement for concrete slabs. [1] This method provides simple equations to design a concrete slab based on the output from a finite element analysis software.
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below ).
Arching or compressive membrane action (CMA) in reinforced concrete slabs occurs as a result of the great difference between the tensile and compressive strength of concrete. Cracking of the concrete causes a migration of the neutral axis which is accompanied by in-plane expansion of the slab at its boundaries.
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]
The initiation time is related to the rate at which carbonation propagates in the concrete cover thickness.Once that carbonation reaches the steel surface, altering the local pH value of the environment, the protective thin film of oxides on the steel surface becomes instable, and corrosion initiates involving an extended portion of the steel surface.
The tension failure loads predicted by the CCD method fits experimental results over a wide range of embedment depth (e.g. 100 – 600 mm). [2] Anchor load bearing capacity provided by ACI 349 does not consider size effect, thus an underestimated value for the load-carrying capacity is obtained for large embedment depths.
Although multidimensional finite element calculations of creep and moisture diffusion are nowadays feasible, simplified one-dimensional analysis of concrete beams or girders based on the assumption of planar cross sections remaining planar still reigns in practice. Although (in box girder bridges) it involves deflection errors of the order of 30%.