Thermal analysis of reinforced concrete beams and frames

Abstract

It is known that changes in temperature may produce stresses in concrete structures of mainly the same order of magnitude as the dead and live loads in some cases. However, the stresses due to temperature are produced only when the thermal expansion or contraction is restrained. In this paper, the behavior of reinforced concrete beams and frames is studied under thermal loads, with the presence of dead and live loads, in order to examine the effect of temperature variation. The beams and frames are modeled properly by accounting for material nonlinearity, particularly cracking. Different temperature gradients, uniform, linear and nonlinear, are considered. The finite element method is employed for conducting the analysis utilizing the computer code ABAQUS. The obtained results of the studied cases reveal that material modeling of reinforced concrete beams and frames plays a major role in how these structures react to temperature variation. Cracking contributes to the release of significant portion of temperature restrain and in some cases this restrain is almost eliminated. The response of beams and frames deviates significantly based on the temperature gradient, linear or nonlinear; hence, the nonlinear temperature gradient which is the realistic profile is important to implement in the analysis.

Keywords

• Concrete
• Beam
• Frame
• Thermal loads
• Material nonlinearity
• Finite element