Numerical and experimental study of the BUEEP connection using an inner box

• Published in: Journal of constructional steel research Vol. 193; p. 107264
• Main Authors: Rafiei Tekieh, Seyed Mahdi, Zandi, Amir Peyman, Pashaei, Malek Houshang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2022
• Subjects: Bolted extended end-plate connection; Box-column; Continuity plate; Cyclic test; Inner box; Moment steel connection; Inner box; Box-column; Cyclic test; CJP; Moment steel connection; CP; FEM; BUEEP; Bolted extended end-plate connection; Continuity plate; IB; LVDT; NDT; UT
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2022.107264

In this paper, a prefabricated part called Inner Box is proposed to be embedded in box-columns at the connection zones to solve the well-known problems of the box-column connections, namely the inaccessibility of the interior side of the box-columns for both continuity plates welding and bolt tightening. The inner box contains four side-plates and two continuity plates assembled like a cube. Nuts are encased with specially designed gadgets welded to inner box side-plates preparing for a direct bolted connection. Fabrication, nondestructive tests, and repairs of typical inner boxes are practically and economically justified. For optimization study on IB dimensions, non-linear finite element modeling is used. Then a full-scale specimen of the optimized connection is tested under cyclic loading. Test results, according to AISC 341–22, approve the connection's seismic qualification in the range of the tested dimensions. The test specimen and FEM models show good agreement. Finally, some design criteria are proposed by numerical sensitivity studies. [Display omitted] •A new connection part called “Inner Box” is proposed to eliminate built-up box columns fabrication and erection problems.•By using the inner box, continuity plate welding and weld NDTs would become much easier.•By using the inner box, beam to box-columns direct bolted connections would become possible.•Numerical and experimental studies have proved inner box desirable performance for the BUEEP moment resistant connection.