Seismic Fragility Analysis Of Steel Frame With New Energy-dissipated Beam-to-column Connections

During the Northridge earthquake(1994)and the Hyogolcen-Nanbu earthquake(1995).many steel structures were severely damaged.After the earthquake investigation,many beam-to-column connections were brittle damaged.Since then,the new energy-dissipated beam-to-column connections become the focus of research.However,many scholars carry out very in-depth researches,but most of them are limited to the parametric analysis of single class connections and the plastic hinges themselves.The research object is single,and seldom applied to the overall structure,which the study is also basically limited to deterministic analysis,the results can not be comprehensive to determine the seismic performance of the structure.In this paper,the seismic performance of all kinds of new energy-dissipated beam-to-column connections is summarized and compared,and then the energy-dissipating connections with excellent performance are applied to the steel frame structure,wlich focuses on the performance-based probabilistic seismic fragility analysis,The conclusion can provide a theoretical reference for the design and application of new energy-dissipated nodes.In this paper,the multi-scale model is built in ABAQUS finite element software.Maximum vertex displacement angle(RDA)and maximum interlaminar displacement angle(ISDA)are used as the seismic demand parameters,and peak ground acceleration(PGA)is used as the seismic strength parameters.Based on IDA And the analysis method of Pushover,the probability earthquake demand and seismic capacity respectively were analyzed.On this basis,the seismic fragility analysis of the structure is carried out.The results show that the opening on beam web connection and the flange plate stiffened connection have their ow n advantages for the steel frame.The opening on beam web connection can more effectively reduce the seismic fragility and be applied to buildings with higher structural safety requirements.For some high-rise buildings with high ductility requirements,the opening on beam web connection can be applied to them.In the design of structures,it is worth noting that the "strong column weak beam" design concept should be strengthened for the flange plate stiffened connection,the relative stiffness of the column should be checked when strengthening the beam side.if necessary,the column can be properly reinforced to avoid column out of brittle damage;for the opening on beam web connection,the plastic hinge in the beam end can not be effectively transfered if round hole is weakend too little;if weakened too much,the overall damage to the structure are happened because of a large number of frame beams in advance failure,so the weakening of the beam must be appropriate and appropriate,as far as possible to ensure that the structural ductility level is not reduced while reducing the vulnerability.