NEW DUCTILE STEEL FRAMES LIMITING DAMAGE TO CONNECTION ELEMENTS AT THE BOTTOM FLANGE OF BEAM-ENDS : Part 3 Experimental evaluation of composite effects and damage to concrete slab

Abstract

This paper presen 窰 s an experimental s加 dy on new moment frame cDmections designed to restrict damage to specific connection elemcnts placed at the bottem flange of the beam ． Composite effects and damage to the concrete slab were addressed in these tests ． Composite action Ied to a roughly 98 ％ increase in initial elastic stiffness and 20％ increase in yield strength ． Mcanwhile ， the plastic strain at the specific connection elements was increas巳 d by only 20％ ， indicating thaUhe plastic rotation capacity of the connections was hardly affected by tho presence of the concrete slab ． And the feature ofthe design forcing the connection Io rotate about the top fiange was beneficial in reducing damage to Ihc ooncrete slab ．

Evaluation of plastic energy dissipation capacity of steel beams suffering ductile fracture under various loading histories

“…17−29) from four cyclic loading tests [10][11][12][13] are also included in the database ( Table I). Eight of them are steel beam specimens with 50 mm thick end plates (PL in Table I); the others are beam-column subassemblies with wide-flange beams and RHS columns.…”

“…Five large-scale beam-column subassemblies were tested under different loading histories with incremental, decremental, and constant amplitudes in order to understand the influence of the diversity of the loading histories on the beams. In addition, 24 specimens from six published steel beam-column subassembly tests [8][9][10][11][12][13] were also investigated. Based on the complete experimental database, the energy dissipation capacity of the steel beams with the failure mode of ductile fracture under various cyclic loading histories was evaluated.…”