September 2004 – The Third Edition of the SDI Diaphragm Design Manual (DDM3) continues the evolution of building shear resistance presented in the First and Second Editions of this manual. The manual is based on research, testing, and analysis sponsored by the Steel Deck Institute and its member and associate member companies, under the direction of Dr. Larry D. Luttrell, Technical Advisor to the SDI, since 1965.

The Third Edition is based on the 2004 Supplement of the 2001 North American Specification for the Design of Cold-Formed Steel Structural Members. The manual explains the method developed to calculate the capacity of diaphragms using steel roof decks or composite steel floor decks and the use of the diaphragm load tables.

The diaphragm tables have been revised and adapted for ease of use with either the allowable stress design (ASD) or load and resistance factor design (LRFD) methods according to the North American Specification for the Design of Cold-Formed Steel Structural Members. With over 130 pages of diaphragm load tables using welds, screws and other mechanical fasteners, the manual is a comprehensive resource for the design profession. There are 16 example problems for ASD and LRFD design and equations to check fasteners for the combined effect of shear and tension.

PLEASE NOTE: The following updates to our Diaphragm Design Manual Third Edition, No. DDM3 are now available:

• Appendix IX Addendum – Simpson Strong-Tie XL Screws – Diaphragm Diaghragm Design Manual, Third Edition
• Appendix VIII Addendum – For Screws by Hilti Pin X-HSN 24 – Diaphragm Diaghragm Design Manual, Third Edition
• Appendix VII Addendum – For Screws by Hilti and Simpson Strong-Tie – Diaphragm Diaghragm Design Manual, Third Edition
• Appendix VI Addendum – Diaphragm Diaghragm Design Manual, Third Edition
• Errata to Diaghragm Design Manual, Third Edition