In structural collapse scenarios, beam to column connections can be subjected to large rotations as the structure deforms, in addition to large axial forces associated with the development of catenary action. The capability of the connections to sustain these large rotations and axial forces can be a critical factor in whether alternate load paths can be developed, bridging over failed members. Because of this, it is important in structural collapse analysis that the interaction of bending moment and axial force, and their combined effect on connection failure, be accurately represented in the modeling of connections. This paper considers the modeling of two different typed of steel bolted connections for collapse analysis. One connections is a single plate shear connection, and the other type of connection is a moment connection with welded flanges: a welded unreinforced flange, bolted web (WUF-B) connection. Detailed finite element models of the connections are developed, consisting of solid elements with sufficient refinement to represent shear failure of bolts and bearing failure of plates. Model predictions are compared with available experimental data, and good agreement is observed. Simplified models are also developed, consisting of beam and spring elements interconnected by rigid links. The simplified models are developed on the basis of the detailed models, but can be executed much more rapidly, facilitating analysis of complete structural systems. In both the detailed and simplified models, a range of connection properties are considered, including different types, sizes, and numbers of bolts. The influence of these factors, as well as the beam span length, on the behavior of the connections in collapse scenarios is also considered.
Conference Dates: September 19-23, 2011
Conference Location: Seattle, WA
Conference Title: 14th International Symposium on Interaction of the Effects of Munitions with Structures
Pub Type: Conferences
Buildings, Connections, Finite element method, Nonlinear analysis, Progressive collapse, Seismic design, Steel structures.