Analysis On Seismic Performance Of Steel Frame Reinforced Connections

Steel frame reinforced connections are new types of beam-column connectionsstudied more and more by experts at home and abroad in recent years, the workingprinciple is expand local beam flange in a certain distance from the column surface,make the plastic hinge form at the beam flange away from the weld between beamand column, reach the design purpose of plastic hinge relocation, effectively protectthe weak parts of the beam-column joints, improve the ductility of the structure, avoidbrittle failure and realize the design thought of the seismic code “strong node weakcomponent”.This article carried out the experimental research and finite element simulation ofside-plate reinforced connection, flange-expanded connection, cover-platereinforced connection and flange-plate reinforced connection specimens and anordinary bolt welding connection specimen, and the main contents include:113reduced scale ratio of1/2specimens were designed and produced to take lowcycle reciprocating loading test. There’s no overall instability phenomena during thewhole loading process, all reinforced ductility connections can effectively transfer theplastic hinge away from the beam end, they have full hysteresis curves, good ductilityand energy dissipation capacity; Geometric parameters of strengthen parts of the beamflange make great influence on the mechanical properties and seismic performance ofthe connections, with the increase of the length and thickness of the strengthen partsof the beam flange, the bearing capacity increased, while the hysteretic performance,ductility and energy dissipation capacity were reduced.2Using the ANSYS finite element analysis software to set25nonlinear finiteelement numerical models, analyze the failure pattern, stress distribution law, limitbearing capacity, hysteretic performance, ductility performance, energy performanceof different structural form beam-column joints under low cycle reciprocating loading.The results show that: the finite element simulation and experimental results obtaineda good consistency, reinforced connections can effectively improve the bearingcapacity of the node and have better ductility and hysteretic performance than the ordinary bolt welding node. Strengthen parameters of the beam flange affectobviously on the mechanical properties and seismic performance of the connection.It’s suggested that the linear part of the side-plate is as long as (0.33-0.93）times of thebeam flange width, as wide as (0.2-0.33) times of the beam flange width; the linearpart of the expanded-flange is as long as (0.55-0.95) times of the beam flange width,as wide as (0.2-0.33) times of the beam flange width. the linear part of the side-plateis as long as (0.5-0.85) times of the beam flange width, as thick as (0.7-1.0) times ofthe beam height. the linear part of the side-plate is as long as (0.5-0.8）times of thebeam height, as thick as (1.0-1.3) times of the beam flange thickness.3Taking the ultimate bearing capacity of the connections under low cyclereciprocating loading are equal for the premise, the paper design the strengthenparameters of the side-plate reinforced connection, flange-expanded connection,cover-plate reinforced connection, flange-plate reinforced connection specimens,and finite element models are established to research the mechanical properties,seismic performance and degradation characteristics of the connections, explor thequality performance of different structural form of reinforced connections, providevaluable reference for the seismic design of the steel frame connections and theapplication of new connections in engineering.4Detailed introduction about the design process of different structure form ofreinforced connections was given through a engineering application design exampleof the steel frame reinforced ductility connections to provide more intuitive andreliable theory and design reference for the practical application in engineering.