Creep behavior is associated with time-dependent, stress-induced changes in the strain and deformation of a structural member. Creep, along with shrinkage (decrease in direct strains over time) and aging (change in elastic modulus with age), are time-dependent material behaviors which may be applied to concrete objects using staged-construction analysis. Staged construction is a nonlinear-static application available to CSI Software with Ultimate Levels and Features. Additional information may be found in the CSI Analysis Reference Manual (Staged Construction, page 396). Staged construction is also necessary for modeling creep, shrinkage, and relaxation within tendons. Tendon elastic shortening, however, is automatically implemented with any software package.
Each of these time-dependent behaviors are specified according to CEB-FIP parameters (Comite Euro-International Du Beton, 1993). Creep formulation may follow full integration or an expedited Dirichlet series approximation (Ketchum, 1986). The CSI Analysis Reference Manual (Time-dependent Properties, page 85) presents further details.
|Time dependent properties first steps (SAP2000)||Basic introduction to using time dependent material properties||SAP2000|
|Staged construction in buildings||Guidelines for setting up staged construction and interpreting the staged-construction results.||SAP2000|
|Staged construction of a five-story column||Creep application, addition of nodes to deformed configuration, and verification against manual calculations are given for the staged construction of a five-story column.||SAP2000|
- Verification Example 16, available through Help > Documentation
- Shrinkage section
- Ghali, A., Favre, R., Elbadry, M. (2002). Concrete Structures: Stresses and Deformations: Analysis and Design for Serviceability (3rd ed.). London, England: Spon Press.
- SEGAN: Analysis of curved segmentally-erected prestressed-concrete box-girder bridges (website), legacy software from Earthquake Engineering Online Archive - computational code for creep implementation