A new model for beam rigid connection to double I-shaped column's web

Due to the extensive use of built-up I-shaped columns in steel frames, especially in Iran, conducted studies have so far only considered the rigid connection between beams and the major axis of I-shaped profiles. Hence, box columns have become the most commonly used structural elements in two-way moment frames. However, less complicated, less time-consuming, and less costly, construction of double profiles in building sites, rather than that of box columns in fabrication companies, suggest the novel idea of a rigid connection to the minor axis of built-up I-shaped columns by haunch plates. Initially, data from a rigid beam to column flange connection were used to verify numerical analysis and result, owing to the unavailability of experimental data concerning rigid beam to web connections. Thereafter, seven numerical models of a one-sided sub-assembly of beam to column web connection with different arrangements of the haunch plates, and vertical and horizontal continuity plates were designed and assessed by means of finite element method using ABAQUS. After that, parameters such as restraint percentage, stiffness, strength, plastic hinge location, and also ductility under cyclic loads were calculated for each model. Results indicated that adding haunch plates along with horizontal and vertical continuity plates in the panel zone of double I-shaped columns can lead to significant increases in connection stiffness, as it restricts relative rotation of the tip of top and bottom connection plates. Consequently, models number HP6 and HP7, with respective stiffness values of 27.4 and 28.67, can be categorized as rigid connections by AISC.