Title: High-Rise Concrete Buildings: Shrinkage, Creep, and Temperature Effects

Author(s): Henry G. Russell

Publication: Symposium Paper

Volume: 97

Issue:

Appears on pages(s): 125-138

Keywords:

DOI: 10.14359/6898

Date: 2/1/1987

Abstract:
When designing high-rise reinforced concrete buildings, length changes of vertical members caused by time-dependent effects must be considered. For design purposes, long-term deformations of columns, walls, and caissons may be considered to consist of instantaneous deformations, shrinkage deformations, and creep deformations. In most cases these are non-reversible deformations. Short-term time-dependent deformations are caused by temperature changes and lateral loads. These are generally reversible. Instantaneous deformations depend largely on vertical load, cross-sectional dimensions of member, and modulus of elasticity of steel and concrete at the age when the load is applied Creep deformations depend on concrete stress, size of member, amount of reinforcement, and creep properties of concrete at different ages. Shrinkage deformations generally depend on concrete materials, quantity of water in the mix, size of the member, and amount of vertical reinforcement. When the above factors are considered together with the actual stress histories and realistic material properties, it is possible to predict with reasonable accuracy the shortening of vertical members in high-rise buildings. Temperature changes occur on a daily and seasonal basis. The exposed portions of a building respond to these changes with induced forces or deformations that depend on degree of expo-sure and boundary conditions of the structural members.