Bifurcation Analysis of Columns of Composite Materials with Thermal Variation

Abstract

Civil structures are, normally, subjected to gravitational and thermal loads. The association of the effects of these loads should be the object of analysis when the loss of stability of the slender columns was verifying. In the case of reinforced concrete structures, temperature variations induce internal stresses in addition to gravitational ones since they are caused by the difference in the thermal properties of steel and concrete. Since the structure is a slender system, its stiffness was divided into two parts. In the first one, the properties of the concrete were introduced, including cracking and creep, doing the equations obtained at the time-dependent mathematical process. In the second, the geometric, the construction imperfections and the internal efforts mobilized by the temperature variation were considered. Additionally, strains and thermal loads were considered together. At the end, the values of critical buckling loads for different moments of interest were determined.

Keywords:
thermal variation; critical buckling load; mathematical analysis; slender columns