Web crippling of thin-walled cold formed steel cassettes

The resistance of cold-formed thin-walled steel cassettes against local transverse forces, i.e. the web crippling capacity, was investigated both experimentally and numerically using finite element analysis. Both unreinforced (flat) cassette webs and webs with longitudinal stiffeners situated on only one side of the web mid-line were studied. The calculation of the web crippling capacity of this type of stiffened webs is not included in current design codes. However, if cassettes are designed as continuous over two or more spans, the resistance against local transverse forces has to be verified. The study included a total of 52 structural tests. Finite element models were developed and validated on the basis of the test results and very good agreement was achieved. This was followed by an extensive parametric study of the influence of different cross-sectional parameters on the resistance against local transverse forces of longitudinally stiffened webs. Recommendations concerning the design of the cassette web section are given based on the results.