Bridge Response due to Temperature Variations


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CAIT project no.: CAIT-UTC-034

Fiscal Year: 2012/2013

Status: Final

Rutgers-CAIT Author(s): Paul Barr, Ph.D., Associate Professor, Patrick Szary, Ph.D

External Author(s): Russ Scovil, Research Project Manager

Sponsor(s): Utah Department of Transportation, FHWA - RITA

Summary:

The inclusion of uniform temperature effects for bridges has traditionally been incorporated in design by allowing for expansion and contraction through the utilization of bearings and joints or deformations of the piers and abutments in the case of integral abutment construction. However, as a result of the growth in the multi-modal transportation system, more complex and longer-span bridges are now being constructed, requiring new material technologies and design methodologies.  These modern bridges are increasing the necessity for accurate accounting of thermal effects to achieve the desired in-service performance.  In general, temperature effects not only include these uniform changes but also changes in temperature gradients throughout the day.  A vertical nonlinear temperature gradient over the height of the bridge cross section is caused by the relatively low thermal conductivity of the concrete deck and the variation of ambient temperature magnitudes with time. This nonlinear temperature gradient induces longitudinal stresses over the height of each of the girders across the width of the bridge that can lead to cracking and unacceptable service conditions if not taken into account properly.