Effects of temperature - Concrete Structures: Stresses and Deformations - page 350

Precast concrete liquid storage tank, Gold Beach, Oregon. (Courtesy Prestressed
Concrete Institute, Chicago.)

10.1 Introduction
It is well known that changes in temperature can produce stresses in concrete
structures of the same order of magnitude as the dead or live loads. However,
the stresses due to temperature are produced only when the thermal expan-
sion or contraction is restrained. High tensile stresses due to temperature
often result in cracking of concrete; once this occurs, the restraint to thermal
expansion or contraction of concrete is gradually removed and its stresses
reduced.
Most design codes require that temperature e ects be considered, although

in many cases very little guidance is given on how this can be done. Thermal
stresses can be substantially reduced and the risk of damage caused by tem-
perature eliminated by provision of expansion joints and su

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cient well-
distributed reinforcements. For this reason and because of the complexity of
the problem, many structures are designed by following empirical rules for
details (e.g. Equation (E.1) ), with virtually no calculation of the e

ects of
temperature. However, for important structures exposed to large temperature
variations, e.g. structures with members of relatively large depth exposed to
the weather, it is appropriate to have assessment of the magnitude of tem-
perature variations and the corresponding stresses. This chapter attempts to

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