The Calculation of Deflections of Reinforced Concrete Members -A Rational Approach


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Title: The Calculation of Deflections of Reinforced Concrete Members -A Rational Approach

Author(s): Heinrich Trost

Publication: Special Publication

Volume: 76


Appears on pages(s): 89-108

Keywords: beams (supports); cracking (fracturing); creep elasticity; moments of inerti bending moments; concre properties; deflection; a; reinforced concrete; te slabs; modulus of shrinkage; structural analysis.

Date: 10/1/1982

The proposed calculation procedure is based on a reference deflection at the interesting point of the uncracked concrete member. This reference deflection is calculated on the basis of the existing distribution of the gross section stiffness-in analogy to the usual determination of the design forces in statically indeterminate systems-- as available from tables or handbooks. Then this reference value, either for the maximum service load or for the sustained load when time-dependent effects are concerned, is multiplied by reinforcement-dependent coefficients given in figures or calculable from closed formulae in order to obtain the initial deflection and the time-dependent deflection due to creep and shrinkage. The probable deflection, as the prognostic value of interest and in which the deflection-reducing effect of the reinforcement and the tension stiffening is considered, is determined by interpolation between the deflections in the limit states according to the acting moment level.