34-007 (13) 780 CMR: STATE BUILDING CODE COMMISSION
elements when the design loads are as required elsewhere by
this code.
Each piece of native lumber produced shall be stamped with
the name and registration number of the producer in accordance
with the rules and regulations of the State Building Code Com-
mission. In addition, all native lumber shall bear an approved
mark identifying the species of wood. In lieu of the stamp
bearing the name and registration number and species identifi-
cation, a certification bearing the same information may be
provided by the producer for pre-cut or remanufactured lumber
in accordance with the rules and regulations of the Commission.
When native lumber is used, it shall be subject to the following
requirements:
1. Sizing criteria: For lumber sized in accordance with the
American Softwood Lumber Standard PS-20-70, figures for
maximum fiber stress and modulus of elasticity for framing
grade No. 2 will be used in establishing span and spacing
characteristics for all structural members.
2. Stress increases: Lumber which is sized in excess of the
dimensions established by the American Softwood Lumber
Standard PS-20-70 for the given nominal size referenced
shall be allowed to have a maximum fiber stress increase
above that provided in Item 1 above in proportion to the
increased bearing capacity of the cross-section as pro-
vided in Table 2103-1 or as calculated.
2103.4 Metal: Steel structural elements in walls and partitions
may be either hot rolled structural steel shapes or bar sections
or members cold formed to shape from steel sheet, strap or
plate, or a fabricated combination thereof. Members shall be
straight and free of any defects which would significantly affect
their structural performance. The allowable span for steel
headers in bearing walls shall not exceed the values set forth
in Table 2103-4.
2103.4.1 Aluminum materials: Aluminum structural elements in
walls and partitions shall be constructed of materials and de-
signed in accordance with accepted engineering practice.
2103.5 Masonry construction: For additional information on
masonry construction, see Article 8 of the basic code.
2103.5.1 Corbelling: Corbels may be built only into solid ma-
sonry walls twelve (12) inches or more in thickness. The pro-
jection for each course in such corbel shall not exceed one-third
(1/3) of total thickness of the wall when used to support struc-
tural members, and not more than six (6) inches when used to
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