Effect of Creep and Shrinkage on RC Frames with High Beam Stiffness

Abstract

The most widely used procedure available in literature for determining creep and shrinkage effects in RC building frames, designated herein as approximate procedure (AP), has been recommended for buildings having flexible slab systems (low beam stiffness) and with a number of stories not exceeding 30. Recently an accurate procedure termed as consistent procedure (CP) has been developed which is applicable for low as well as for high beam stiffness and requires no restriction on the number of stories. In this paper, using CP, behavioral studies are reported for frames with high beam stiffness. For a 60 story frame, studies are reported for steel ratio, volume to surface ratio, and number of stories. It is shown that the effect of inelastic deflections on final elastic forces is complex and strongly depends upon percentage of reinforcement and volume to surface ratio. When the effect of these two parameters mutually reinforce each other, the load transfer among columns can be significant. On the other hand when these effects balance each other, the load transfer is low.