The 2011 edition represents a major update from the former edition both in technical requirements and in layout. The Code and Specification are written as legal documents so that they may be adopted by reference in general building codes. The Code covers the design and construction of masonry structures, with subjects covered ranging from quality assurance to the details and development of reinforcement. Compliance with the Specification is required by the Code to control materials, labor and construction. The commentaries present background details, committee considerations, and research data used to develop the Code and Specification. The Commentaries are not mandatory and are for information only. Many revisions and enhancements have been made including: • a recalibration of allowable stresses; • the addition of provisions for infill masonry; and • a refinement of the quality assurance/special inspection provisions for masonry that includes references to relevant requirements for each inspection task. (TMS 402-11/ACI 530-11/ASCE 5-11) (TMS 602-11/ACI 530.1-11/ASCE 6-11)