Creep In Concrete, What is creep in concrete, Explain creep in concrete

Creep in concrete speaks to what is creep in concrete, why does creep in concrete occur and explain creepin concrete.

It is a long term event when placed under stress from its own weight, the weight of other permanent building structure or components. It can also be due the force of prestressing and will cause the concrete to gradually and permanently shorten over a period of months or years.

On occasion this change in dimensions is of sufficient magnitude that it must be accounted for and included in the design and detailing of the building systems. An example of this may, when a brick veneer cladding system is supported on a concrete building frame, the shrinkage of the concrete combined with other factors affecting movement of the masonry require that horizontal movement joints be designed into the cladding system to accommodate the differential movement between the cladding and the building structure.

If these joints are not provided or if they are too narrow and have insufficient capacity to absorb movement, the cladding system can fail as it becomes compressed, in part by the shortening of the concrete structure.

As a general rule sitecast building frames can be expected to shorten in height under the influence of their own weight and other dead loads at the rate of 1/16 inch for every 10 feet (1/2 mm per meter) of building height.

As noted in Wikipedia:

The rate of this deformation is a function of the material properties, exposure time, exposure temperature and the applied structural load. Depending on the magnitude of the applied stress and its duration, the deformation may become so large that a component can no longer perform its function — for example creep of a turbine blade will cause the blade to contact the casing, resulting in the failure of the blade. It is usually of concern to engineers and metallurgists when evaluating components that operate under high stresses or high temperatures. It is a deformation mechanism that may or may not constitute a failure mode. Moderate creep in concrete is sometimes welcomed because it relieves tensile stresses that might otherwise lead to cracking.

Unlike brittle fracture, creep deformation does not occur suddenly upon the application of stress. Instead, strain accumulates as a result of long-term stress. Creep is a "time-dependent" deformation.


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