Numerical testing of steel beam-to-column bolted extended end-plate connection with haunches

Abstract

During the European research project entitled EQUALJOINTS (European pre-Qualified steel JOINTS) [1], which recently concluded, the matter of providing a set of pre-qualification procedures for moment resisting beam-to-column connections which are currently used in Europe has been addressed. During the experimental campaign 24 specimens with bolted extended end-plate connections with haunches were tested. The current paper presents the numerical model which has been developed such that numerical testing may be performed to further investigate specific details. In what concerns the material, an isotropic material model has been calibrated and used based on tensile tests of coupons extracted from the specimens to model the actual plastic behaviour. Moreover, the imperfections of the beam have been taken into account using a bucking analysis to model as accurate as possible the specimens tested. The interaction between parts has been modelled using contacts with different interaction laws. The model used for the bolt has been calibrated such that the preloading and failure replicate the behaviour of the actual bolts used in the experiments.

Effect of The Haunch Angle and Stiffener Types on Column-Beam Connection Behaviour Under Static Loading

“…As suggested by Ruffley (2011) [46], 3D solid elements were used to simulate the finite element models. As shown in Figure 7, C3D8R [47] (first order reduced integration continuous element), a six-edge solid element type that allows nonlinear geometric and material behavior, is used in all models [12,21]. Based on a study carried out for the finite element mesh sensitivity, the size of mesh for different elements determined as 10mm for endplate and column stiffeners, 5mm for bolts, 20mm for beam and haunch, 15mm for beam stiffeners, 10mm for column panel zone area, and an approximate mesh size of 100mm for places far from the connection.…”

“…Several studies have been carried out on the reinforcement of moment resisting connection before the Northridge earthquake. The studies indicated that the plastic hinge formed in the beam with the effect of the haunch on the lower flange of the beam and it was suitable for earthquake resistant structure design [10][11][12][13][14][15].…”

“…studies showed that haunched connections consume 20% more energy than normal joints in cyclic horizontal loading. Moreover, haunched connections have proven to be a suitable solution for seismic applications with large plastic deformation demands [10][11][12][33][34].…”

Simplified Modelling of Failure in High Strength Bolts under Combined Tension and Bending

“…The same problem can be highlighted in the connections of replaceable links, where the bolts undergo large deformations (Figure 1b). In the literature there are some models that can be used to reproduce the stripping of the nut for HV bolts or shank fracture for HR bolts [9][10][11][12][13][14], but a model capable of fully capturing the behaviour of HV bolts under combined tension and bending is missing [4].…”

“…The same problem can be highlighted in the connections of replaceable links, where the bolts undergo large deformations (Figure 1b). In the literature there are some models that can be used to reproduce the stripping of the nut for HV bolts or shank fracture for HR bolts [9][10][11][12][13][14], but a model capable of fully capturing the behaviour of HV bolts under combined tension and bending is missing [4]. Much research [4][5][6][7][8][9][10][11][12][13][14][15][16][17] was accomplished in recent years to develop models able to replicate, with a good level of accuracy, the damage and failure of bolts subjected to a specific action such as pure tension or shear [9][10][11][12][13][14], but most of them require the computation of the parameters needed to implement the failure mechanism of the materials and of the joints themselves.…”