Code Sections and Analysis - The Analysis of Irregular Shaped Structures - page 20

• Determine by tests the distances required for ties and collectors to spread loads
into the diaphragm.
• Evaluate by tests the current assumptions associated with subdiaphragms.
• Determine the effects of the size and location of openings on the force distribu-
tion and deformation of diaphragms.
• Determine the necessity of code-enforced aspect ratios.
Guidelines for the Design of Horizontal Wood Diaphragms, ATC-7, Applied Technol-
ogy Council, Redwood, Calif., 1981.
The guideline 4 was prepared by H. J. Brunnier Associates and guided by an advi-
sory panel comprised of Noel R. Adams, Edward F. Diekmann, Byrne Eggenberger,
Ronald L. Meyes, Roland L. Sharpe, and Edward J. Teal.
The document was considered to be the state of the art at the time of publication.
Most of the information contained in the guideline continues to be of value and rele-
vance today. Twelve design examples are included in the guide, in addition to discus-
sions of the topics listed below. Some of the concepts are not fully developed; however,
there is a considerable amount of information contained there for both the novice and
the experienced professional.
• Basic diaphragm discussions
1. Basic components and stresses
2. Girder analogy
3. Truss analogy
4. Moment couple series
• Diaphragms with openings
• Continuous diaphragms
• Subdiaphragms
• Irregular diaphragms
• Diagonal and straight sheathed diaphragms
• Diaphragm deflections
• Load transfer through the diaphragm
John R. Tissell and James R. Elliott, APA Research Report 138, Plywood Diaphragms ,
APA from E315H, APA—The Engineered Wood Association, Engineering Wood
Systems, Tacoma, Wash., 2000.
The report 9 included 11 tests of diaphragms on panelized systems, high-load dia-
phragms, diaphragms with openings, field-glued diaphragms, and diaphragms with
framing spaced at 5 ft. Of particular interest is Appendix E, which provided an example
of the analysis of a diaphragm with openings. The example was based on the design
method described in ATC-7, which was developed by Edward F. Diekmann, S.E.
D. E. Breyer, J. F. Fridley, D. G. Pollock, and K. E. Cobeen, Design of Wood Structures
ASD , McGraw-Hill, New York, 2003.