Thermal Stress Analysis of Reinforced Concrete Members in Cracked Sections

Many reinforced concrete structures are commonly subjected to thermal effects due to various environmental conditions or service functions. Such thermal effects lead to the development of thermal stresses and, consequently, the formation and propagation of cracks in the concrete member. The cracks reduce the member stiffness and thereby alleviate thermal stresses. Most analyses of reinforced concrete structures subjected to thermal gradients employ the conventional linear-elastic uncracked method, which often overestimates the thermal bending moments. A nonlinear analytical approach is proposed to determine thermally induced moments in reinforced concrete structures subjected to simultaneous thermal and mechanical loading. The results obtained from this procedure are compared against those found by the elastic uncracked concrete method for structures such as beams, continuous bridges, and liquid containments. The non-linear cracked concrete method more accurately predicts the flexural response, while the results generated with the linear elastic uncracked method prove to be overly conservative and overestimated.