Experimental and numerical investigation on Q690 high strength steel beam-columns under cyclic lateral loading about weak axis

摘要

Recently structural members fabricated of high strength constructional steels in civil and building engineering has been widely explored. However, their usage in earthquake zones is still restricted by seismic standards worldwide due to its poor ductility. In order to attain potential seismic application, this paper conducted five cyclic lateral loading experiments on H-shaped beam-columns fabricated of Q690D high strength structural steel. The tested members were cyclically bent about the weak axis. It was recognized that the low-fatigue fracture of edge fiber around bottom cross-section was the main failure mode. Besides, the hysteretic curves, cyclic backbones and energy dissipation characteristics were thoroughly discussed. The ultimate inter-storey drift was greater than the limitation of 1/50. All tested beam-columns exhibit favorable cyclic deformability and energy dissipated ability. To further study the influence of several factors, a series of FEA simulations were performed through verified numerical models. Ductile damage behaviors and advanced cyclic constitutive relationships were considered to improve the simulation performance. The influences of plate component slenderness and axial load ratio on seismic performance of steel beam-columns were thoroughly discussed. It is concluded that there exist interdependence characteristics between different influential factors on seismic performance.