Model Development and Experimental Validation of Damage-Avoidance Structural Connections with Unbonded Post-Tensioned Prestress

摘要

In the field of earthquake engineering, damage-free structural design methods havereceived significant research attention in recent years due to the large economiccost associated with sacrificial design methods. In particular, jointed precastconcrete and steel connections with unbonded, post-tensioned prestress has beenthe focus of a significant amount of research. These systems provide controlledinelastic response through gap-opening at the beam-column interface instead ofthrough yielding and damage of the structural elements. The development of amodel that captures all the associated characteristics and provides an accurateprediction of response adds significant confidence in response simulationsA time-incremental model of the connection behaviour is developed thataccounts for yielding of the prestressing tendons, reduction of the prestressingforce, friction between the post-tensioning tendons and the containing ducts, andasymmetry from non-centrally located tendons. The model is formulated using acombination of incremental versions of the Menegotto-Pinto and Ramberg-Osgoodtype, providing a smooth, continuous loading and unloading approximation to thepiecewise linear behaviour. The model is validated against experimental results foran 80% full-scale jointed precast concrete connection with inputs drifts up to 4%.Results show very good agreement with the experimental results, with errorsgenerally less than ±5%. Overall, the model is generalisable to other connectionsusing steel and concrete rocking connections that utilise this type of damage-freedesign approach and is a useful tool for evaluation of connection designs.