The Seismic Behavior Research On Partially Encased Concrete Column-Steel Beam Joint

Partially encased concrete composite structure has high bearing capacity, ductility andenergy dissipation of good performance, convenient construction, economic superiority andother advantages, so it is used in the old buildings in the reinforcement and reconstructionand high-rise structure of new buildings. At present, the partially encased concrete beamsand columns were researched At home and abroad, but for the partially encased concretecolumn-steel beam joint are rare, there is no system design method and calculation of maturetheory system, which hindered its popularization and application in practical engineering.Therefore, the experimental and theoretical study of the partially encased concrete column-steel beam joint has certain significance in theory and engineering practice.According to the research status at home and abroad, in this paper, partially encasedconcrete column and steel beam in this type of4different structure of the joint is the pseudo-static test. Through the applied horizontal low cyclic load, get node of P-Δ hysteresis curve,the strain distribution of each connected component board domain, the failure mode of theorder and development degree, study the end plate thickness, stiffening plate, backing plate,and other key parameters on the bearing capacity, stiffness, ductility and energy dissipationperformance influence.According to the experimental results, we can conclude that: the increase of thethickness of the end plate and back plate setting can improve the bearing capacity of thespecimen, and set the vertical stiffening slabs little effect on the bearing capacity of thespecimen. When the end plate thickness increases from10mm to12mm, the bearingcapacity of the specimen increased by15.8%; in setting the column flange of the back platespecimen, the bearing capacity is increased by22.7%. The bearing capacity of the specimendegradation coefficient is relatively stable; the average of around0.97, cycles is smallerinfluence on bearing capacity of the specimens. The thickness of the end plate and the back plate are the main factors that influence the stiffness degradation, the increase of thethickness of end plate and back plate setting can improve the initial stiffness of the specimen,and set the vertical stiffener effect on the stiffness of the specimen is not obvious. When theend plate thickness increased from10mm to12mm, the initial stiffness increased by58.6%;the backing plate specimen with initial stiffness is increased by17%. All specimens has goodductility, the ductility coefficient is between3.56~4.42, with an average of3.99, greater thannormal concrete structure ductility coefficient of2.0. All specimens of the energy dissipationperformance is also better, equivalent viscous damping coefficient values between0.62~1.74,coefficient is higher than the coefficient of steel reinforced concrete structure0.3, reinforcedconcrete structure0.1. Therefore, this kind of node has a good seismic performance.On the basis of the experimental study, using the large general finite element softwareABAQUS to partially encased concrete columns and steel beam connection node wassimulated by finite element method. Comparative analysis showed that, the finite elementsimulation results are in good agreement with the test results, According to the test andnumerical analysis results for this type of combination node, and put forward some measures,such as setting the triangle end plate, node at the steel core columns correspond to the steelbeam flanges to set horizontal stiffeners, stiffeners haunched beam flange level, and so on.These measures will improve the node bearing capacity and stiffness, and improve theseismic performance of the node.