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Twenty eight days is a long wait to determine if desired strengths are going to be obtained, so three-day and seven-day strengths can be useful to predict the ultimate 28-day compressive strength of the concrete. A 25% strength gain between 7 and 28 days is often observed with 100% OPC (ordinary Portland cement) mixtures, and between 25% and 40 ...
Idealisation of arching action forces in laterally restrained slab. 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 ...
In structural and mechanical engineering, the shear strength of a component is important for designing the dimensions and materials to be used for the manufacture or construction of the component (e.g. beams, plates, or bolts). In a reinforced concrete beam, the main purpose of reinforcing bar (rebar) stirrups is to increase the shear strength.
The formula to calculate average shear stress τ or force per unit area is: [1] =, where F is the force applied and A is the cross-sectional area.. The area involved corresponds to the material face parallel to the applied force vector, i.e., with surface normal vector perpendicular to the force.
The modified compression field theory (MCFT) is a general model for the load-deformation behaviour of two-dimensional cracked reinforced concrete subjected to shear. It models concrete considering concrete stresses in principal directions summed with reinforcing stresses assumed to be only axial.
Earthbag of weak soil with no steel can be half the shear strength of unreinforced adobe, which is easily damaged in earthquakes. New Zealand's code detailing and plans allow unreinforced adobe walls to survive almost 0.6 g forces (comparable to Ss values for 2% probability of excedance in 50 years), but earthbag needs stronger soil to match ...
Concrete spalling from the ceiling of an office unit (interior) in Singapore, possibly due to rebar corrosion. Reinforced concrete can fail due to inadequate strength, leading to mechanical failure, or due to a reduction in its durability. Corrosion and freeze/thaw cycles may damage poorly designed or constructed reinforced concrete.
Early research (Bathurst and Jarrett, 1988) [13] found that cellular confinement reinforced gravel bases are "equivalent to about twice the thickness of unreinforced gravel bases" and that geocells performed better than single sheet reinforcement schemes (geotextiles and geogrids) and were more effective in reducing lateral spreading of infill under loading than conventional reinforced bases.