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Eng. Dan Iancu, Eng. Gabriel Florea, Eng. Diana Valentina Lobodan


This article aims to highlight the importance of long-term effects
when calculating the deformations of the reinforced concrete elements, based on the Romanian, European and
American codes, given the significant negative effect of this phenomenon.
The purpose of the article is to highlight the difference that arises between the neglect and
consideration of long-term effects in the calculation of reinforced concrete elements.


In the current design context, the national construction market addresses requirements to
reduce the construction costs, corroborated with the requirement of designing floors
with increasingly generous spans, unassisted by beams. According to the standards in force, the deformation of
an element or structure must not affect its proper functioning or appearance.
The appropriate limit values of the deflections must be fixed, considering the nature of the construction,
, the finishes, the nonstructural partitions and accessories, as well as the function of the building.
Deformations must be limited to values compatible with the deformations of other elements
connected to the structure, such as partition walls, windows, finishes applied on horizontal surfaces, MEP grids or other finishes. In
certain cases, a limitation of deformations may be necessary to ensure the proper functioning
of equipment or appliances placed on the structure, or to avoid the formation of puddles on
the roof terrace.
Shrinkage and creep are time-dependent concrete properties that have
a significant negative impact on the deformations of concrete elements. The SR-EN
1992-1-1-2004 standard recommends that their effects be considered for checks at
service limit states.
When considering the effect of creep, it is recommended to
evaluate the effects in the quasi-permanent of load combination, independently of the situation in
the project considered – permanent, transient or accidental.