Prediction of Cracking in Reinforced Concrete Structures.
Prediction of Cracking in Reinforced Concrete
Structures.
(3056 K)
Carino, N. J.; Clifton, J. R.
NISTIR 5634; 53 p. April 1995.
Available from:
National Technical Information Service
Order number: PB95-220448
Keywords:
building technology; concretes; cracking (fracturing);
creep; reinforced concretes; restrained shrinkage
Abstract:
The useful life of a buried concrete, containment
structure for low level nuclear waste may be controlled
by the loss of its load-bearing capacity or an increase
in permeability. The latter factor is controlled by the
general degradation of the concrete and by the presence
of discrete cracks resulting from externally applied
loads or from restraint to normal volume changes. To be
able to predict the effects of cracks on permeability,
it is necessary to understand the causes and mechanisms
of discrete crack formation in reinforced concrete
structures. The objective of this report is to provide
an overview of the design and behavior of reinforced
concrete members and to discuss the factors affecting
the formation of cracks in hardened concrete. The
underlying philosophy of modern reinforced concrete
design is presented, and it is shown that it allows for
the formation of cracks of controlled widths under
service loads. Models for predicting the width of
flexural cracks are reviewed. Factors affecting drying
shrinkage cracks and approximate methods for considering
them are discussed. An example is provided to
illustrate how to determine whether drying shrinkage
cracks will develop under specific conditions. This is
followed by a discussion of techniques to predict the
number and widths of drying shrinkage cracks. Finally,
there is a discussion of the interaction between
flexural and drying shrinkage cracking. The report is
directed to the general audience who is unfamiliar with
the structural aspects of reinforced concrete.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899