Structural design - Civil engineering

Description of Table s These tables are used to determine thickness of sheathing and spacing of supports based on material used and loading. Both of the tables are used together, the first table gives minimum thickness regardless of load and the second table gives span and thickness information for different applied loads. The two tables you will need to use is Table 2304.7(1) Allowable spans for lumber fl oor and roof sheathing and Table 2304.7(3) Allowable spans and loads for wood structural panel sheat hing and single -floor grades continuous over two or more spans with strength axis perpendicular to supports. Example of Perpendicular Installation Page 1 of 7 Definitions Subfloor: the layer of wood material that is installed on top of the floor joists to prov ide a surface that the floor will be installed on. Floor Sheathing: 4 foot by 8 foot plywood boards with varying thickness laid out on and nailed to floor joists. Diagonal Subfloor Boards: square -edged or tongue -and -groove, no longer than eight inches wide and no less than 25/32 inch thick. Joist Spacing: the distance between each floor joist. Species Group 1: Apitong, American Beech, Birch, Douglas -Fir 1, Kapur, Keruing, Western Larch, Sugar Maple, Pine, Southern Pine, Tanoak Species Group 2: Port Orford C edar, Cypress, Douglas -Fir 2, Fir, Western Hemlock, Lauan, Black Maple, Mengkulang, Red Meranti, Mersawa, Pine, Sweetgum, Tamarach, Yellow -Poplar Species Group 3: Red Alder, Paper Birch, Alaska Cedar, Subalpine Fir, Eastern Hemlock, Bigleaf Maple, Pine, Re dwood, Spruce Species Group 4: Apsen, Cativo, Cedar, Cottonwood, Pine Page 2 of 7 How to Use Table 2304.7 (1) - Lumber Perpendicular to supports Diagonally to Supports Surfaced Dry Surfaced Unseasoned 24” Span = 3/4 ” Floor or 5/8” Roof 16” Span= 5/8” Floor 24” Span = 25/32 ” Floor or 11/16" Roof 16” Span = 11/16 ” Floor Surfaced Dry Surfaced Unseasoned 24” Span = 3/4 ” Floor and Roof 16” Span= 5/8” Floor 24” Span = 25/32 ” Floor or 25/32" Roof 16” Span = 11/16 ” Floor Choose either Sheathing Grades or Single Floor Grades Choose Panel Span Rating and Panel Thickness Choose whether sheathing is for Roof or Floor How to Use Table 2304.7 (3) - Plywood Page 3 of 7 Table 2304.7 ( 1) Page 4 of 7 Table 2304.7 (3) Page 5 of 7 Example Problem Question : What is the minimum thickness of sheathing required for a 16” that is diagonally to supports and is surface unseasoned for a floor? Answer : First, look at table 2304.7 (1). Second, look at the column labeled diagonally to support. Third, look at the column under diagonally to supports, labeled surfaced unseasoned. Last, look at the row under the span column labeled 16”, and look at the number at the end of the row that corresponds with the 3 rd step. Answer is 11/16. Exercises Question: What is the minimum thickness of sheathing required for a 24” that i s perpendicular to supports and is surfaced dry for a roof? Answer: 5/8 Question: What is the maximum span without edge support, and what is the total load of a roof with a 32/16 span? Answer: Either 15/32”, ½”, 5/8”, for the panel thickness. 28” for maxi mum span without edge support, and 40 psf for the total load. Page 6 of 7 References  http://en.wikipedia.org/wiki/Blocking_%28construction%29  http://www.schmeling.com/reference/pdf_files/ply wood_span_ratings.pdf  https://www.google.com/search?q=si&ie=utf -8&oe=utf -8&aq=t&rls=org.mozilla:en -US:official&client=firefox - a&channel=sb#channel=sb&q=sheathing&rls=org.mozilla:en -US:official  https://bblearn.nau.edu/bbcswebdav/pid -2019788 -dt -content -rid -19487763_1/courses/ 1141 -NAU00 -CM -220 -SEC1 - 2312.NAU -PSSIS/Resources/Wood%20Design/2304.7%281%29.jpg  https://bblearn.nau.edu/bbcswebdav/pid -2019788 -dt -content -rid -19487765_1/courses/1141 -NAU00 -CM -220 -SEC1 - 2312.NAU -PSSIS/Resources/Wood%20Design/2304.7%283%29.jpg  IBC 2006, https://bblearn.nau.edu/bbcswebdav/pid -2019788 -dt -content -rid -19487773_1/co urses/1141 -NAU00 -CM - 220 -SEC1 -2312.NAU -PSSIS/Resources/Wood%20Design/cm220 -IBC -2006 -wood.pdf Page 7 of 7