| Based on the previous studies, in order to further research and further perfect the theory of the seismic behavior of box-joint region standard connection with steel-concrete composite, the specimen had been tested under cyclic loading. The hysteretic behavior, carrying capacity, the story drift ductility index, energy dissipation capacity, strength and stiffness degradation have been investigated in detail. The strain along the length direction, the width direction and the height direction of beams were determined. The load-displacement curve and the momentrotation curve were obtained in this test. The results showed:(1) The story drift ductility index of specimen μ≈4.05, elastic ratio of story deflection rotationφy≈0.0101 rad, elastic-plastic ratio of story deflection rotationφu≈0.0411 rad. It shows that the specimen has excellent elastic ductility and elastic-plastic ductility. After the skin plate and the column stiffeners weld was failure, the specimen also kept good carrying capacity.(2) The energy dissipation ratio E≈1.79, equivalent viscous damping coefficients is 0.285. It has better seismic performance and the composite effect can improve the energy dissipation ability, so the composite effect can not be neglected in designing.(3) The plastic hinge position on A side beam is approximately 125 mm from column and on B side beam is approximately 150 mm.Because of its distance is extremely close to skin plate, under the influenced by plastic hinge that only by strengthen or weaken the beam-end can realize the "strong joint and weak components".(4) At the moment of maximum thrust, the skin plate has produced strain up to 640 MPa, so the Z-direction steel should be adopted to prevent the steel plate from laminated tearing.(5) The strength degradation of this new type of stud welded nodes on steel-concrete composite beams is no obvious, strength degradation is among 0.88~1.0. When the weld between skin plate and bottom beam flange failed, the stiffness degradation is obviously and showed a linear sharp drop, the hysteretic curve began to show an inverse sigmoid curve. To some degree, the energy dissipation capacity is reduced. Therefore, to improve the weld quality is the key to ensure steel frame beam of anti-seismic Performance.Based on experimentation, the numerical simulation of the test was carried out by using a large-scale nonlinear finite element code ABAQUS 6.14-1. And added data which was difficult to acquire from test. The paper introduced the common constitutive relationships of concrete and steel in application for simulation of composite structures. SF-1 of concrete was simulated by using plastic-damage constitutive model, steel used Von.Mises yield criterion, and the strengthening criterion used mixed hardening rule which include the isotropic and the anisotropic of steel. Accurate analysis the stress distribution of steel beam and column and the strain of concrete slab. The result gave a good fit to the experimental release data. |
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