ABSTRACT
The design of concrete bridges for temperature fluctuations has traditionally been a simple matter. Longitudinal movements induced by the maximum expected average temperature changes, typically ±20°C, are accommodated by the provision of sliding joints, bearing displacements, or by a flexible pier design. It is, however, only comparatively recently that thermally-induced stresses in bridge structures have received much attention. In part, this results from the introduction of stiff, efficient prestressed sections that have been developed over the past 20 years, which are more sensitive to strain-induced stresses, of which temperature stresses are an example. Reports of distress induced in European prestressed bridges by temperature gradients1,2 began to surface in the 1960s and 1970s. In New Zealand, interest was stimulated in the late 1960s by severe cracking of Auckland’s New Market Viaduct, a major urban prestressed concrete box girder motorway bridge. Measurements of the crack widths indicated a strong correlation with ambient temperature and solar radiation.
