Abstract
This paper presents a simulation scheme suitable for a sub-structure pseudo-dynamic test on a planar flexible steel frame following a bending-shear type interaction. Nodal displacement or force components are classified into two categories: one is a condensed vibration component subject to dynamic loading, and the other is a dependent component subject to quasi-static force constraint. The vibration components are solved by an explicit integration scheme of central finite difference, where an expression in modal coordinates is adopted in an attempt to omit unstable responses of high-frequency modes. The dependent components are solved by a scheme to correct the force imbalance due to various non-linearity. In this scheme an appropriate control is run simultaneously with the specimen, and its behavior is used to extrapolate the specimen's restoring force. This scheme is successfully applied to the hybrid simulation on a 2-story steel frame with semi-rigid partial-strength joints.
