Seismic Behavior of Extended End-Plate Connections Subjected to Cyclic Loading on the Top-Side of the Column

Abstract

The extended end-plate connections provide excellent performance in resisting seismic loads in high-risk areas. Most scholars’ experiments and finite element studies on this type of joint are focused on the method of applying displacement loads on the beam tip, while the method of applying displacement on the column side has not been the subject of further study. However, the load transmission mechanism of this type of connection is not completely consistent in actual engineering, as the design concept of “strong column weak beam” does not apply to all joints. Therefore, in this paper, the lateral displacement of the applied column is used to simulate the seismic horizontal force to study the mechanical properties of the connection joints of the “weak column and strong beam” under the limit state of earthquake action. Based on the two internal columns (IC-EP1/2) and two edge columns (EC-EP1/2), the failure modes, strength, stiffness, moment–rotation curve, skeleton curve, ductility, and energy dissipation of this type of connection were studied. Experiment results indicated that this type of connection features semi-rigid and partial strength joints. The connection rotation angle of all specimens in the test exceeds 0.05 rad, which suggests it is an ideal seismic joints. Besides, the relationship between the thickness of the end-plate and the diameter of the bolt has a greater impact on the failure mode of the joint. The finite element (FE) analysis models were established for the above connection. The numerical model was validated against experimental results and showed acceptable consistency.

Parametric Analysis and Stiffness Investigation of Extended End-Plate Connection

“…The moment-rotation responses for all specimens are illustrated in Figure 4 , and the test results are provided in Table 2 . (The specimens IC-EP1/2 and EC-EP1/2 refer to previous research work [ 31 ]), and the specimen IC-EP3/EC-EP3 are newly added test data. Figure 4 a,b shows that slight differences existed between the west connection and east connection.…”

“… Details of joint specimens (dimensions in mm): ( a ) Detail drawing of the connection; ( b ) layout of the end-plate and bolts; ( c ) overall size of intermediate column (IC) joints [ 31 ]. …”

“… Material constitutive model: ( a ) Bolt constitutive model and ( b ) steel constitutive model [ 31 ]. …”

“…To further study the mechanical behaviors of the extended end-plate under the column top-side loading, this paper includes three main phases. The first phase is based on our previous experimental research [ 31 ] using the finite element analysis (FEA) for verification, which was based on the previous three intermediate column joints (IC-EP1/2/3) and side column joints (EC-EP1/2/3). While the second phase focuses on the parameter study of the 144 (3D) finite element model by changing the geometric dimensions for effective parameters, such as column section, beam length, end-plate thickness, and bolt diameter to determine the influence of these parameters on semi-rigid characteristics such as bending resistance and initial rotational stiffness values.…”

Analytical Model for the Fatigue Analysis of Steel Joints by Clamps According to the Lever Length

“…Therefore, it is necessary to assess the fatigue behaviour of this type of joint, especially depending on the features that determine its operation (the lever lengths). There are numerous research papers on the behaviour of classic bolted connections [10][11][12][13][14][15][16][17], many of them focused on fatigue. For example, Zampieri et al [18] carried out a review of the fatigue resistance of bolted shear connections, Bartsch et al [19] performed an analysis of the fatigue strength of end plate connections with prestressed bolts, and Liu et al [20] showed a simplified modelling strategy based on continuous damage mechanics for the evaluation of cumulative fatigue damage in metal bolted joints.…”