DESIGN OF STEEL FRAME COVER PLATE CONNECTED JOINTS WITH LOW YIELD POINT STEEL “DUCTILE FUSES”

Low yield point steel with low yield strength, high ductility and high energy dissipation capacity is used for steel frame joints. It dissipates seismic energy, is replaceable after earthquakes and provides a high-quality solution for structures with resilience requirement. To propose a design for a steel frame connection with low yield point steel "ductile fuses", a nonlinear numerical model was established by using ABAQUS. The model was verified by typical static tests of steel frame joints with bolted connections. The influence of different impact factors on the performance of this kind of joints was explored, and how these impact factors influenced the "structural fuse" was investigated. Subsequently, the design method was proposed and verified by using an example of practical engineering design. The results indicated that the width of the joint gap, the thickness of the web cover plate and the beam width had little influence on the actual bearing capacity coefficient of the joint and the function of "structural" fuse effect. The position of splicing, the height of the beam and the thickness of the flange cover plate were the key factors of the actual bearing capacity coefficient of the joints. The "structural fuse" will be prematurely ineffective if the design is nonviable. The relationship between the critical value of the design bearing capacity coefficient and the position of the joint and the height of the beam was established by data fitting. When the design bearing capacity coefficient is less than the critical value, the "structural fuse" works normally. When the design bearing capacity coefficient is larger than the critical value, the effect of ‘structural fuse’ gradually decreases.