The combination of subcritical damage growth and creep deformation can cause delayed failure of concrete materials. Such a time-dependent failure behavior adds a new consideration in design of concrete structures. To investigate this behavior, a time-dependent constitutive model for concrete is proposed. The model is anchored by integration of the continuum damage mechanics and nonlinear creep theory. It captures several essential mechanisms responsible for delayed failure behavior of concrete, which include instantaneous softening damage, plasticity, subcritical damage growth, and nonlinear creep. The model is calibrated by the creep experiments on concrete specimens under uniaxial compression and three-point bending. It is shown that the model can well capture the time-dependent deformation and failure of concrete structures under a wide range of loading levels. The contributions of different individual mechanisms to the overall structural response are investigated. The calibrated model is then used to simulate the response of a reinforced concrete frame under sustained loading. The simulation yields the stress-life curve, which is an essential metric describing the delayed failure behavior of concrete structures.
Bibliographical noteFunding Information:
X. Ren and Q. Wang gratefully acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 52078361 ) and from the Innovation Program of Shanghai Municipal Education Commission, China (Grant No. 2017-01-07-00-07-E00006 ).
© 2021 Elsevier Ltd
- Concrete structures
- Delayed failure
- Instantaneous damage
- Subcritical damage growth