Web Crippling Behavior of Floor Joist/Rim Members in Built Assemblies

This paper presents the results of a pilot study of the web crippling performance of two common exterior load-bearing wall conditions (rim joist and rim track with a framing joist) in light framed cold-formed (light-gauge) steel construction. The intent of the study was to develop some preliminary data on the web crippling performance of built assemblies. The test results show that the ultimate strength for the two web crippling conditions considered may be greater than the sum of the individual strengths of the components (based on current American Iron and Steel Institute Specification equations). Further, on the basis of the configurations tested, it appears that the measured higher strengths may be due to a beneficial distribution of load at the corners of a track section. The tests also showed that although the measured strengths may be high, the associated cross-sectional deformations tend to be relatively large. For gravity load design, this deformation may be treated as a serviceability limit state, however, where lateral load design is a concern, this deformation may impact the performance of a braced wall. Thus, it may be prudent to impose a deformation limit on web crippling design equations.