D.C. Mun. Regs. tit. 12, r. 12-A2304
Strike Section 2304.11 of the International Building Code and insert new Section 2304.11 and Table 2304.11 in its place in the Building Code to read as follows:
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.
Strike Sections 2304.11.1 through 2304.11.4 of the International Building Code in their entirety and insert new Sections 2304.11.1 through 2304.11.4 in their place in the Building Code to read as follows
Details of heavy timber structural members. Heavy timber structural members shall be detailed and constructed in accordance with Sections 2304.11.1 through 2304.11.1.3.
Columns. Minimum dimensions of columns shall be in accordance with Table 2304.11. Columns shall be continuous or superimposed throughout all stories and connected in an approved manner. Girders and beams at column connections shall be closely fitted around columns and adjoining ends shall be cross tied to each other, or intertied by caps or ties, to transfer horizontal loads across joints. Wood bolsters shall not be placed on tops of columns unless the columns support roof loads only. Where traditional heavy timber detailing is used, connections shall be by means of reinforced concrete or metal caps with brackets, by properly designed steel or iron caps, with pintles and base plates, by timber splice plates affixed to the columns by metal connectors housed within the contact faces, or by other approved methods.
Floor framing. Minimum dimensions of floor framing shall be in accordance with Table 2304.11. Approved wall plate boxes or hangers shall be provided where wood beams, girders or trusses rest on masonry or concrete walls. Where intermediate beams are used to support a floor, they shall rest on top of girders, or shall be supported by an approved metal hanger into which the ends of the beams shall be closely fitted. Where traditional heavy timber detailing is used, these connections shall be permitted to be supported by ledgers or blocks securely fastened to the sides of the girders.
Roof framing. Minimum dimensions of roof framing shall be in accordance with Table 2304.11. Every roof girder and not less than every alternate roof beam shall be anchored to its supporting member to resist forces as required in Chapter 16.
Partitions and walls. Partitions a nd walls shall comply with Section 2304.11.2.1 or 2304.11.2.2.
Exterior walls. Exterior walls shall permitted to be cross-laminated timber meeting the requirements of Section 2303.1.4.
Interior walls and partitions. Interior walls and partitions shall be of solid wood construction formed by not less than two layers of 1- inch (25 mm) matched boards or laminated construction 4 inches (102 mm) thick, or of 1- hour fire-resistance-rated construction.
Floors. Floors shall be without concealed spaces. Wood floors shall be constructed in accordance with Section 2304.11.3.1 or Section 2304.11.3.2.
Cross-laminated timber floors. Cross- laminated timber shall be not less than 4 inches (102 mm) in actual thickness. Cross- laminated timber shall be continuous from support to support and mechanically fastened to one another. Cross- laminated timber shall be permitted to be connected to walls without a shrinkage gap providing swelling or shrinking is considered in the design. Corbelling of masonry walls under the floor shall be permitted to be used.
Sawn or glued- laminated plank floors. Sawn or glued- laminated plank floors shall be one of the following:
Roof decks. Roofs shall be without concealed spaces and roof decks shall be constructed in accordance with Section 2304.11.4.1 or 2304.11.4.2. Other types of decking shall be an alternative that provides equivalent fire resistance and structural properties. Where supported by a wall, roof decks shall be anchored to walls to resist forces determined in accordance with Chapter 16. Such anchors shall consist of steel bolts, lags, screws or approved hardware of sufficient strength to resist prescribed forces.
Cross-laminated timber roofs. Cross-laminated timber roofs shall be not less than 3 inches (76 mm) nominal in thickness and shall be continuous from support to support and mechanically fastened to one another.
Sawn, wood structural panel, or glued-laminated plank roofs. Sawn, wood structural panel, or glued-laminated plank roofs shall be one of the following:
D.C. Mun. Regs. tit. 12, r. 12-A2304