jar546
Forum Coordinator
The modification in Section 2308.5.6 now explicitly includes the word 'exterior' in its requirements for clarity. Additionally, conflicting information previously found in Section 2308.6.6.2 has been removed. The revised section mandates that exterior cripple walls, which support one or more floors, must be reinforced with either solid blocking or sheathing. This is due to the observation that these walls tend to move sideways and collapse in moderate to severe earthquakes. Reinforcement through sheathing or blocking increases the wall's rigidity.
For structures located in Seismic Design Categories A, B, and C, interior cripple walls, whether part of an interior wall line beneath an interior braced wall or merely supporting the floor above, do not require bracing with blocking or sheathing. This is because such walls are enclosed within sturdier exterior foundation walls made of concrete or concrete masonry unit blocks, ensuring they move in tandem with the floors and exterior walls during seismic activities.
In Seismic Design Categories D and E, the bracing of cripple walls is now restricted to walls up to 14 inches in height, which must be solidly blocked along both interior and exterior sides. Consequently, buildings in these categories are limited to a single story with either a slab-on-grade foundation or a crawlspace formed by studs no taller than 14 inches, featuring solid-blocked cripple walls as detailed in Table 2308.2.1. Cripple walls exceeding 14 inches are classified as an additional story, thus prohibiting a building considered one-story over such cripple walls in SDC D and E. The regulation also provides specific guidelines regarding the extent of solid blocking in cripple wall studs, particularly for ventilation and access purposes.
For structures located in Seismic Design Categories A, B, and C, interior cripple walls, whether part of an interior wall line beneath an interior braced wall or merely supporting the floor above, do not require bracing with blocking or sheathing. This is because such walls are enclosed within sturdier exterior foundation walls made of concrete or concrete masonry unit blocks, ensuring they move in tandem with the floors and exterior walls during seismic activities.
In Seismic Design Categories D and E, the bracing of cripple walls is now restricted to walls up to 14 inches in height, which must be solidly blocked along both interior and exterior sides. Consequently, buildings in these categories are limited to a single story with either a slab-on-grade foundation or a crawlspace formed by studs no taller than 14 inches, featuring solid-blocked cripple walls as detailed in Table 2308.2.1. Cripple walls exceeding 14 inches are classified as an additional story, thus prohibiting a building considered one-story over such cripple walls in SDC D and E. The regulation also provides specific guidelines regarding the extent of solid blocking in cripple wall studs, particularly for ventilation and access purposes.