Decrease of Tensile Creep Response under Realistic Restraint Conditions in Structures

摘要

The creep behavior of concrete members is of major importance for their serviceability. Besides its negative influence on deflections under load impact, creep strains are supposed to positively reduce the hardening induced restraint stresses after temperature equalization - which is an essential assumption for today's design practice of neglecting the superposition of hardening induced restraint stresses with later restraint stresses during life time. A number of different experimental studies, however, have indicated that the assumed positive effect of creep is highly overestimated. This can mainly be explained by disproportionately diminishing tensile creep responses after relaxation under the maximum of all ever experienced tensile stresses. Based on detailed information on the experimental studies with passive restraint frames as well as comparative tensile creep tests, this contribution presents new insights on tensile creep behavior under realistic conditions in concrete structures.