Simplified procedure for creep and shrinkage effects in reinforced concrete frames

This paper describes a simplified procedure for evaluation of creep and shrinkage effects in reinforced concrete frames having low shear beam stiffness. In this procedure the inelastic axial forces, which get generated progressively with time in various substructures, are assumed to arise only at an instant time. The procedure designated as AP2, is much more simplified than the recently developed consistent procedure (CP), which is highly elaborate. This procedure yields more accurate results than the procedure already available in literature, AP1, for frames with low shear stiffness of beams. Studies are reported for a range of chosen typical creep parameters for 40-, 60-, and 80-storied frames and for chosen values of shear stiffness of beam as a nondimensional parameter-stiffness factor. It is shown that for a given accuracy the range of stiffness factor for which AP2 is to be used is much higher than that for AP1. The estimate of the stiffness factor beyond which the use of CP is warranted is also indicated.