and Head, School of Civil and Environmental Engineering
The University of New South Wales
paper addresses the effects of shrinkage on the serviceability of concrete
structures. It outlines why
shrinkage is important, its major influence on the final extent of cracking and
the magnitude of deflection in structures, and what to do about it in design.
A model is presented for predicting the shrinkage strain in normal and
high strength concrete and the time-dependent behaviour of plain concrete and
reinforced concrete, with and without external restraints, is explained. Analytical procedures are described for estimating the final
width and spacing of both flexural cracks and direct tension cracks and a
simplified procedure is presented for including the effects of shrinkage when
calculating long-term deflection. The
paper also contains an overview of the considerations currently being made by
the working group established by Standards Australia to revise the
serviceability provisions of AS3600-1994, particularly those clauses related to
Creep; Cracking; Deflection; Reinforced concrete; Serviceability; Shrinkage.