It is well known that the ultimate resistance of a concrete member under sustained load compared to the resistance of the same member loaded by instantaneous load can be considerably smaller. One of the reasons for this is creep-cracking interaction which for a sustained load causes an increase of damage zone and reduction of ultimate capacity. This effect is stronger if the structure was previously loaded by cyclic loading. In the present paper is demonstrated that the microplane model for concrete which is coupled in series with the linear creep model (Maxwell chain model) is able to account for the above phenomena. The three-dimensional finite element analysis of concrete specimen loaded in uniaxial compression and the analysis of a headed stud anchor loaded by monotonic and cyclic shear load was carried out. It is shown that the shear resistance of the anchor under sustained load reduces by 15%. Moreover, the reduction of the load-capacity increases if the anchor has previously been loaded by cyclic load.
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