AISC 360 solver
BCDsteel calculations are in accordance with “ANSI/AISC 360-16 Specification for structural steel buildings July 7, 2016”. The user may specify either load and resistance factor design (LRFD) or allowable strength design (ASD) provisions.
Direct analysis method or Effective length method
BCDsteel implementation of effective lengths for AISC 360 is intended for use with the direct analysis method. When BCDsteel automatically defines members, it sets the effective length for flexural buckling = the unbraced length. This applies to all members including [cantilevers] and [columns in moment-frame systems]. Alternatively, the Effective length method can be used for structures that satisfy the limitations specified in Appendix 7.
Tapered or stepped members
Non-uniform members (tapered and or stepped) are analysed as an equivalent uniform member using the properties of each of the 9 equi-spaced sections along the member. Each utilisation ratio UR will be the “maximum” value for all 9 section properties.
BCDsteel follows AISC 360 exactly when possible.
Ch E5(a), E5(b) is included as an option for equal leg angle compression members. Ch E5(b) provides a significant advantage compared with Ch H2, particularly at higher L/ry values.
For bending of singly symmetric I-sections, BCDsteel checks lateral-torsional buckling for each flange as required by Ch F1(d). The buckling modification factor Cb is evaluated using the equations in the specification and commentary as well as in the referenced documents. This includes a load height factor for destabilizing loads.