International Building Code

SUBJECT: Braced Wall Lines
CHANGE TYPE: Modification

2308.9.3 Bracing. Braced wall lines shall consist of braced wall panels that meet the requirements for location, type, and amount of bracing as shown in Figure 2308.9.3, specified in Table 2308.9.3(1) and are in line or offset from each other by not more than 4 feet (1219 mm). Braced wall panels shall start not more than 8 12.5 feet (2438 3810 mm) from each end of a braced wall line. A designed collector shall be provided if the bracing begins more than 12.5 feet (3810 mm) from an end of a braced wall line. Braced wall panels shall be clearly indicated on the plans. Construction of braced wall panels shall be by one of the following methods: [text unchanged].

CHANGE SIGNIFICANCE:

Braced wall panels regulated by the International Building Code (IBC) have previously been required to start not more than 8 feet from each end of a braced wall line. The 2003 International Residential Code (IRC) requires braced wall panels to begin no more than 12.5 feet from each end of a braced wall line. The code change revises the distance by which braced wall panels are permitted to be placed from the end of a braced wall line to be consistent with the provisions in the IRC. The requirement that a designed collector be provided if the bracing begins more than 12.5 feet from the end of a braced wall line was deleted because it made no sense within the context of the section.

The 2003 IBC required that braced wall panels not start more than 8 feet from each end of a braced wall line, with a designed collector to be provided if the bracing began more than 12.5 feet from the end of a braced wall line. This was a peculiar requirement because according to the code, braced wall panels were not permitted to be more than 8 feet from the end of a braced wall line. (A collector is an engineered structural element that “collects” diaphragm shear and distributes the shear to the vertical resisting elements such as shear walls.) This code change resolves the problem. In order to conform to the prescriptive requirements, the code requires that braced wall panels be located not more than 12.5 feet from the ends of braced wall lines. If they are, then the bracing system does not conform to prescriptive requirements and engineering is required. The design of the collector is an essential part of the engineering for the lateral-force-resisting system.