Thelife-timepredictionoffasteningsystemsundersustainedloadsrequires,amongothers, a suitable numerical solution strategy and viscoelastic constitutive models that can reproduce well the material specific characteristics. The formulation and calibration of viscoelastic models can be based on a topdown approach from observed macroscopic response or, alternatively, a bottom-up…
Thelife-timepredictionoffasteningsystemsundersustainedloadsrequires,amongothers, a suitable numerical solution strategy and viscoelastic constitutive models that can reproduce well the material specific characteristics. The formulation and calibration of viscoelastic models can be based on a topdown approach from observed macroscopic response or, alternatively, a bottom-up approach can be pursued. In the simplest case a fine scale model can represent the system response of bonded and mechanical anchors with contributions of each component, namely (i) concrete, (ii) steel, and (iii) mortar, and the respective interfaces, which are calibrated individually based on quasi- static tests and creep tests. Further homogenization steps allow the derivation of each materials creep response from their respective sources at lower scales hydrates for concrete and the polymer matrix. In this contribution we will analyze and decompose the creep deformations of two typical bonded anchor systems. The visco-elastic behavior of concrete, modeled according to the micro-prestress solidification theory, and of the polymer mortars, represented by a Kelvin-Chain, will be calibrated basedonmacroscopiccreeptestsofsuitablesize. Thebond-lawforthetop-downapproachofbonded anchors, which represents the smeared response of interfaces and mortar layer, will be calibrated on suitable pull-out tests. Sustained load tests on all three types of fastening systems serve for the validation, and if necessary, for the detection of neglected mechanisms.