Behavior of Bolted Steel Slip-critical Connections with Fillers
Borello, Daniel J.; Denavit, Mark D.; Hajjar, Jerome F.
- Behavior of Bolted Steel Slip-critical Connections with Fillers
- Borello, Daniel J.
- Denavit, Mark D.
- Hajjar, Jerome F.
- Date of Publication
- Steel connections
- slip-critical bolted connections
- bolted bearing connections
- filler plates
- This document reports the results of sixteen experiments of bolted slip-critical connections with fillers. Fifteen of the connections used oversized holes and one connection used standard holes to establish a baseline comparison. Such connections with oversized holes are commonly fabricated for use with structures such as long-span trusses, since the use of oversized holes allows erection in-place rather than first assessing fit-up on the ground. Filler plates are used to connect members of different depths or widths. The Specification for Structural Steel Buildings of the American Institute of Steel Construction (AISC, 2005) currently requires connections with oversized holes to be designed as slip-critical at what is termed the “required strength level,” for which a resistance factor (LRFD) φ of 0.85 and a safety factor Ω (ASD) of 1.76 are specified. These slip strengths are typically below values that had been used for years in the Specification for Structural Steel Buildings: Allowable Stress Design and Plastic Design (AISC, 1989). In addition, when fillers are used in these connections, the AISC (2005) provisions do not require changes in the strength calculations, whereas if standard holes are used, options are provided for connection design that include reduction of the bolt shear strength or development of the connection. The sixteen experiments reported herein highlight the behavior of bolted steel connections with oversized holes in which fillers are included and are undeveloped, partially developed, or fully developed. Both single-ply and two-ply filler are investigated, as are welded fillers, and specimens fabricated using either turn-of-the-nut or tension-controlled bolts. Extensive instrumentation was used on the specimens to document the flow of forces through the connection. The results document the slip and shear strengths of these connections, propose formulas for assessing these strengths for the different conditions investigated, provide revised recommendations for design of these types of connections, and include suggestions for further work.
- Newmark Structural Engineering Laboratory. University of Illinois at Urbana-Champaign.
- Series/Report Name or Number
- Newmark Structural Engineering Laboratory Report Series 017
- Type of Resource
- Identifiers: URI or URL
- Copyright and License Information
- Copyright held by the authors. All rights reserved.