Specimen 04: Hybrid simulation of steel cruciform specimen (seat configuration) with vertical loading

This hybrid simulation consists of a physical and an analytical substructure tested using OpenSees and OpenFresco. The physical substructure is of a half-scale steel (ASTM A992 Grade 50) cruciform beam-column subassemblage comprised of a column and 2 half length beams at either end of the column. Specimen 4 is the same as specimen 3 except there is more precompression of the enhanced gravity connection. Specimen 4 also uses the seated-type enhanced gravity connection with vertical loads on each beam to simulate distributed gravity loads. The analytical substructure is a half scale 2D 1-story steel exterior moment frame. This half scale model comes from a larger 3D steel special moment resisting frame building. The test regime was a hybrid simulation with increased scaling, up to 245%, of the Takatori, Japan record. The objective was to evaluate the hysteretic behavior and seismic performance of a new type of enhanced gravity connection.