Classification System for Semi-Rigid Beam-to-Column Connections

Abstract

The current study attempts to recognise an adequate classification for a semi-rigid beam-to-column connection by investigating strength, stiffness and ductility. For this purpose, an experimental test was carried out to investigate the moment-rotation (M-θ) features of flush end-plate (FEP) connections including variable parameters like size and number of bolts, thickness of end-plate, and finally, size of beams and columns. The initial elastic stiffness and ultimate moment capacity of connections were determined by an extensive analytical procedure from the proposed method prescribed by ANSI/AISC 360-10, and Eurocode 3 Part 1-8 specifications. The behaviour of beams with partially restrained or semi-rigid connections were also studied by incorporating classical analysis methods. The results confirmed that thickness of the column flange and endplate substantially govern over the initial rotational stiffness of of flush end-plate connections. The results also clearly showed that EC3 provided a more reliable classification index for flush end-plate (FEP) connections. The findings from this study make significant contributions to the current literature as the actual response characteristics of such connections are non-linear. Therefore, such semirigid behaviour should be used to for an analysis and design method.

Mechanical Modeling and General Analytical Solution for the Dynamic Buckling of Plane Structures Using a Beam-Column Element with Varying End Restraints

“…Thus, element (2,3) can be replaced at node 2 by an equivalent rotational spring whose rigidity acts in parallel with the flexural rigidity of the element (1,2); so that the of this spring is equal to k r1 = 3EI L . Two other situations, corresponding to the presence of a vertical element (3,4) whose node ( 4) is considered articulated, then fixed. As before, one can assimilate elements (2,3) and (3,4) to an equivalent rotational spring whose rigidity acts in parallel with the flexural rigidity of element (1,2); so that by adopting the principle of static condensation, the rigidity of this spring is respectively equal to k r2 = which corresponds to cases (a1-4) then by adopting an embedding at node (1) which corresponds to cases (b1-4).…”

“…Two other situations, corresponding to the presence of a vertical element (3,4) whose node ( 4) is considered articulated, then fixed. As before, one can assimilate elements (2,3) and (3,4) to an equivalent rotational spring whose rigidity acts in parallel with the flexural rigidity of element (1,2); so that by adopting the principle of static condensation, the rigidity of this spring is respectively equal to k r2 = which corresponds to cases (a1-4) then by adopting an embedding at node (1) which corresponds to cases (b1-4). The mechanicals and geometrical characteristics adopted for the frame are: modulus of elasticity : E = 200 kN/mm 2 ; length: L = 1m; section area: A = 13,2×10 -4 m 2 ; moment of inertia: I = 27,7×10 -8 m 4 ; density: ρ = 8050kg/m 3 .…”

“…Previous research on the behaviour of connections shows that such assumptions are not entirely valid and do not represent the real behaviour of nodal connections [3][4][5][6][7][8][9]. They have been adopted in practice for their simplicity in the analysis and design of structures.…”

“…𝐚 = 21β 8 − 8β6 (3186 + 61(α ri + α rj )) + 1620β4 (6408 + 268(α rj + α ri ) + 7α ri α rj )) − 583200β 2 (2808 + 192(α ri + α rj ) + 11α ri α rj ) + 157464000(540 + 52(α rj + α ri ) + 5α ri α rj )) C 1 = 4897760256000 − 32β 10 + 702919296000α ri + 702919296000α rj + 90699264000α ri α rj + 108β 8 (376 + 7α ri + 7α rj ) − 576β 6 (30996 + 1256α ri + 1256α rj + 31α ri α rj ) + 155520β4 (20952 + 1395α ri + 1395α rj + 74α ri α rj ) − 1007769600β 2 (234 + 23α rj + α ri (23 + 2α rj )) (21β 8 − 8β 6 (3186 + 61α ri + 61α rj ) − 583200β 2 (2808 + 192(α ri + α rj ) + 11α ri α rj ) + 157464000(540 + 52(α rj + α ri ) + 5α rj )) + 1620β4 (6408 + 268(α rj + α ri ) + 7α rj )))…”

Nonlinear Analysis of Rotational Springs to Model Semi-Rigid Frames

“…The resolution of the case using an incremental method is only one element of the heuristic: the fundamental difficulty is in modelling the union when the stiffness matrix is not constant throughout the process. In the context of the idea of a tangent stiffness matrix, or simply a tangent matrix, in a non-linear finite element method (FEM), some previous works are still relevant [ 6 , 7 , 8 ].…”