Modeling cyclic loading behavior of jointed precast concrete connections including effects of friction, tendon yielding and dampers

摘要

Reversed cyclic loading behavior of jointed precast prestressed concrete beam-to-column connections are computationally modeled and validated against full-scale experimental results. Response simulations are performed with and without supplemental high force-to-volume (HF2V) energy dissipation devices. The experimental specimen is a three-dimensional corner connection of a jointed precast concrete frame structure, utilizing unbonded post-tensioned tendons consisting of high-alloy, high-strength thread-bars. The joint region is armored, to avoid damage, by providing steel plates at the beam-column (rocking) contact points. The analytical model of the connection is developed to include modifications for the effects of changing connection behavior. These effects are friction within the prestressing system, yielding of the prestressing tendons, reduction or elimination of prestress attributable to prior tendon yield, and directional dependence caused by an asymmetrical prestress system. Particular attention is given to developing a robust model that can accommodate small reversals in the displacement loading. The model is extended to incorporate the effects of the HF2V energy dissipation devices and the associated flexibility from the elements that connect the devices to the structure. Although the model is applied to the use of HF2V (lead extrusion) energy dissipation devices, it is general and can accommodate any non-linear rate-dependent damper. The computational model is based almost entirely on rational mechanics and shows good agreement with the full-scale experimental observations.