Prepared by the Design of Steel Transmission Towers Standards Committee of the Codes and Standards Activities Division of the Structural Engineering Institute of ASCE. This standard provides requirements for the design, fabrication, and testing of members and connections for latticed steel electrical transmission structures. Covering guyed and self-supporting structures, these requirements are applicable to hot-rolled and cold-formed steel shapes. The standard specifies the design criteria for structure components.members, connections, and guys.to resist design-factored loads at stresses approaching yielding, buckling, or fracture. This new edition, which replaces the previous Standard ASCE 10-97, presents minor changes to the design requirements and introduces new sections on redundant members, welded angles, anchor bolts with base plates on leveling nuts, and post angle member splices. Topics include: loading, geometry, and analysis; design of members, including compression members, tension members, and beams; design of connections, including fasteners, minimum distances, and attachment holes; detailing and fabrication; full-scale structure testing; structural members and connections used in foundations; and quality assurance and quality control. A detailed commentary contains explanatory and supplementary information to assist users of the standard. In addition, one appendix offers 17 design examples, and a new appendix offers guidance for evaluating older (legacy) electrical transmission towers. Standard ASCE/SEI 10-15 is a primary reference for structural engineers designing latticed steel electrical transmission structures, as well as for other engineers, inspectors, and utility officials involved in the electric power transmission industry.