| Beam-column joints connecting earthquake resistance of steel frames have a significant impact. Conventional wisdom is that, welded beams rigidly connected with good seismic performance. But in the United States and Japan’s Kobe earthquake damage in Northridge, rigid connection brittle fracture failure has occurred, the beam did not show the expected plastic deformation, failed to reach the seismic design requirements. Since then, researchers have to find two new ductile nodes, one is " enhanced " node; Another is "reduced " node. However, with the popularization and application of high strength steel, lack these nodes also gradually becoming apparent. Improve the strength of steel at the same time, will inevitably bring about the deterioration of yield improvement and stronger than the plastic deformation capability, so when the whole cross-section along the beam length using high-strength steel, plastic hinge end of the beam to form a curved ability to limit certain extent, the impact of the earthquake consumption can effect. This paper presents a novel combination of steel beams welded joints, in place of the local low-intensity beam steel webs (constant thickness) flange and the rest of the web is still using high-strength steel.For the new node, the paper carried the following research areas:First, determine the size and location of the low-intensity seismic design of steel webs according to our criteria, then determine the range of low-intensity strength steel curved scissors according to the common theory.Then, using the finite element software ANSYS four series of specimens were carried out uniaxial loading and cyclic loading simulation analysis. Discusses the position of low-intensity steel web under unidirectional loading and cyclic loading effects of low-intensity strength steel webs, the length of the low strength steel web stiffeners novel combination of these four factors on the steel beams welded joints the performance of the force size. Low strength steel webs less overall impact on the position of the new composite steel beams welded joints. With the increase of low steel webs position, resilient structure lateral stiffness, maximum floor shear is not, the basic approach, while the yield shear floor, there is a greater change in the energy dissipation coefficient increases Strength low-strength steel and low strength steels length greater impact on the overall innovative steel beams welded joints, improve the bearing capacity and seismic energy dissipation capacity of the structure. A constraint stiffeners, constrains the beam web in improving stiffness and bearing capacity of the structure at the same time, results in strength and stiffness degradation, which is due to the accumulation of plastic deformation nodes, making local buckling phenomenon becomes apparent.Finally, the research work is summarized, pointing out new combinations of steel beams welded joints compared with conventional node can save costs, reduce the overall carrying capacity is small, and energy dissipation capacity has greatly improved. At the same time, pointed out the inadequacies and to study the text of the node to the following comments made. |
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