Application of Volume Factor, CV, for SCL when CV > 1.0
Question: NDS® (2001/2005) Section 8.3.6 states that CV shall be applied simultaneously with the beam stability factor, CL, when CV > 1.0. Should CV be applied to Fb* in calculation of CL or is it intended that CV be applied following calculation of the beam stability factor as follows: Fb’ = Fb* x CV x CL?
Answer: Where CV > 1, it is intended to be applied to Fb* prior to calculation of the beam stability factor, CL. For SCL, application of CV > 1 to Fb* prior to calculation of CL is analogous to application of the size factor for lumber in determination of the appropriate Fb*. The increased value of Fb*, applicable for a fully-braced member, is the appropriate reference value for calculation of the ratio of critical buckling design value to fully-braced reference design value (FbE/Fb*) used to determine CL.
Answer: Where CV > 1, it is intended to be applied to Fb* prior to calculation of the beam stability factor, CL. For SCL, application of CV > 1 to Fb* prior to calculation of CL is analogous to application of the size factor for lumber in determination of the appropriate Fb*. The increased value of Fb*, applicable for a fully-braced member, is the appropriate reference value for calculation of the ratio of critical buckling design value to fully-braced reference design value (FbE/Fb*) used to determine CL.
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