Experimental Study on Thermal Cracking in Reinforced Concrete Members

Reinforced concrete beams, with and without prestressing, are subjected to thermal gradient while the rotations of the beam ends are prevented. The bending moments and the cracking developed by the temperature gradient are monitored. Alleviation of the thermal bending moments due to creep of concrete and due to progressive stiffness reduction with crack formation is studied analytically and compared with the moment values recorded in the experiments. The test series includes beams with variable amounts of non-prestressed and prestressed reinforcements to study their effects on the thermal moments, the crack widths, and the crack spacings. The experimental and the analytical research presented is intended to help structural designers in realistic prediction if the thermal bending moments and to give guidance on the amounts of the prestressed or the nonprestressed reinforcement required to control cracking.