Fysical-engineering model of reinforced concrete frames in compression

Abstract

A calculation of the complementary moments due to second-order effects and the analysis of the stability of reinforced concrete framed structures can be conceived as follows. With the aid of a computer a very large number of M-N-x diagrams can be produced on the basis of the standard specified stress-strain diagrams for concrete and steel. A framed structure is then analysed with an available program which takes account of second-order effects. The flexural stiffnesses EI to be adopted are estimated and corrected with reference to the M-N-x diagrams calculated once before and held in store for the purpose. The present paper discusses the drawbacks ofthis approach and proposes a method of analysis which can be fitted into existing programs for framed structures and dispenses with the large number of stored M-N-x diagrams. It is shown that direct use can be made of the stress-strain diagrams. The results are just as reliable as those obtained by the procedure utilising the M-N-/( diagrams. The method can be applied to total frames and single members in compression as well