As many engineers know, there has been a trend in structural engineering to move from allowable stress design (ASD) procedures to the strength design or load and resistance factor design (LRFD) procedures.

For concrete and masonry, the term "working stress design" was used in the past. For consistency, the term working stress design has recently been discontinued in favor of the term allowable stress design. The term "LRFD" is used in the design of steel and wood structures. The term "strength design" is used in the design of concrete and masonry structural elements.

For masonry design, the 2006 IBC and 2005 edition of the Masonry Standards Joint Committee’s (MSJC) Building Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402) still permits both allowable stress design (Section 2107) and strength design of masonry structures (Section 2108). For concrete structures, the working stress design method was deleted from the 2002 edition of the American Concrete Institute’s Building Code Requirements for Structural Concrete (ACI 318). For structural steel design, the 2005 edition of the American Institute of Steel Construction’s Specification for Structural Steel Buildings, AISC 360-05, is a dual format standard that permits the designer to use either LRFD or ASD methods. The 2006 IBC references the 2005 edition of the National Design Specification (NDS) for Wood Construction, which is also a dual format standard.

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