This warning message is related to the minimum web thickness check according to cl.8.6.1. For each member, program performs the web thickness check according to cl.8.6.1.1 - Serviceability requirement and cl.8.6.1.2 - Compression Flange buckling requirement. If any of the criteria mentioned in the above mentioned clause is not satisfied, a warning message is reported in the output file informing the exact clause number. It is required to modify the web dimension (increase the web thickness or decrease the depth).