Bolted End Plate Research Articles

Behaviour of steel beam-column connections, made using bolted end plates

Simulated earthquake loading was applied to four cruciform specimens, that represented part of a multistorey frame, including the half-beams and half-columns framing into a typical interior joint. This was made by welding plates on to the ends of the beams and bolting these plates to the column flanges using high strength proof loaded bolts. The joints were designed so that recommendations, previously developed elsewhere for monotonic loading, together with the rules given by New Zealand Standard 3404:1977, could be studied. When the existing rules were followed ductile specimens were obtained; however, when some of the joints were deliberately designed to be understrength, failure modes were obtained that were not predicted by the existing simple design methods.

Limit Design of Extended End-Plate Connections

A limit states method for the design of bolted end plate connections has been developed. The design method aims at providing connections whose strength and stiffness are adequate to sustain the ultimate moments of beams in rigid frames designed by plastic analysis. Basic design philosophy relating to strength and stiffness is considered. The force distribution within the joint is derived and design rules are formulated for the different elements of the connection. These include design of bolts, end plates and welds, together with checks on the adequacy of the column flange and web. Certain fabrication effects, such as lack of fit are considered. The paper combines the results of several research programs and reports experimental evidence from each. Mention is made of relevant research in the United States and Europe.

Correlation between 2- and 3-dimensional finite element analysis of steel bolted end-plate connections

Paper presents a part of a comprehensive research program to investigate the behavior of bolted end plates which are being increasingly used for moment-resistant connections between steel structural members. The typical configuration studied consisted of a plate welded to the beam cross section and bolted by two rows of pretensioned high-strength bolts at each flange to the adjacent member. While clearly a 3-D finite element analysis would be more suitable for the problem than 2-D analysis, and more meaningful for comparison with test results, it would also be more complex and demanding. A 3-D analysis would also have been infeasible for the exhaustive parameter studies planned. Hence thirteen bench-mark connections, with dimensions spanning values commonly used in the industry, were analyzed by 2-D and 3-D programs, so that their correlation characteristics could be applied for prediction of other 3-D values from corresponding 2-D results. The programs were based respectively on the constant strain triangle and an eight-noded subparametric brick element. The connections were analyzed elastically, under bolt pretension alone (except for two of them which were not pretensioned), and under half and full service loads. Significant features of the connection modelling and finite element code modification included the iterative determination of the deformed profile of the end plate under the contact (no tension) support restraints, and the simulation of the bolt pretensioning and subsequent moment loading processes. The longitudinal displacement (separation) of the back of the end plate and the vertical plate bending stresses, all at the beam tension flange, obtained from 2-D and 3-D analyses were evaluated; “correlation factors”, defined as the ratio of 3-D value to 2-D value, were determined to be 1.4 for displacement and rotation, 1.2 for average stress, and 1.8 for maximum stress.