2304.11 Heavy Timber Construction
Where a structure, portion thereof or individual structural elements are required by provisions of this code to be of heavy timber, the building elements therein shall comply with the applicable provisions of Sections 2304.11.1 through 2304.11.4. Minimum dimensions of heavy timber shall comply with the applicable requirements in Table 2304.11 based on roofs or floors supported and the configuration of each structural element, or in Sections 2304.11.2 through 2304.11.4. Lumber decking shall be in accordance with Section 2304.9.
MINIMUM DIMENSIONS OF HEAVY TIMBER STRUCTURAL MEMBERS
SOLID SAWN SIZE
LAMINATED NET SIZE
COMPOSITE LUMBER NET SIZE
|SUPPORTING||HEAVY TIMBER STRUCTURAL
|Width, inch||Depth, inch||Width, inch||Depth, inch||Width, inch||Depth, inch|
|Floor loads only
or combined floorand roof loads
Framed sawn or glued-laminatedtimber arches that spring from the
floor line;Framed timber trusses
|Wood beams and girders||6||10||5||101/2||51/4||91/2|
|Roof loads only||Columns (roof and ceiling loads);
Lower half of: wood-frameor glued-laminated arches
that spring from the floorline or from grade
|Upper half of: wood-frame
or glued-laminated archesthat spring from the floor
line or from grade
|Framed timber trusses and other
roof framing; aFramed or glued-laminated
arches that spring from the topof walls or wall abutments
For SI: 1 inch = 25.4 mm.
- Spaced members shall be permitted to be composed of two or more pieces not less than 3 inches nominal in thickness where blocked solidly throughout their intervening spaces or where spaces are tightly closed by a continuous wood cover plate of not less than 2 inches nominal in thickness secured to the underside of the members. Splice plates shall be not less than 3 inches nominal in thickness.
- Where protected by approved automatic sprinklers under the roof deck, framing members shall be not less than 3 inches nominal in width.
Sawn or glued-laminated plank floors shall be one of the following:
- Sawn or glued-laminated planks, splined or tongue-and-groove, of not less than 3 inches (76 mm) nominal in thickness covered with 1-inch (25 mm) nominal dimension tongue-and-groove flooring, laid crosswise or diagonally, 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particleboard.
- Planks not less than 4 inches (102 mm) nominal in width set on edge close together and well spiked and covered with 1-inch (25 mm) nominal dimension flooring or 15/32-inch (12 mm) wood structural panel or 1/2-inch (12.7 mm) particleboard.
The lumber shall be laid so that continuous lines of joints will occur only at points of support. Floors shall not extend closer than 1/2 inch (12.7 mm) to walls. Such 1/2-inch (12.7 mm) space shall be covered by a molding fastened to the wall and so arranged that it will not obstruct the swelling or shrinkage movements of the floor. Corbelling of masonry walls under the floor shall be permitted to be used in place of molding.
Sawn, wood structural panel, or glued-laminated plank roofs shall be one of the following: