Wall & Support Structure Framing

The house’s strength, how much stress can be applied before it permanently fractures or deforms, is what resists the forces of an earthquake. The house’s stiffness, it’s tendency to either stay in or return to its original form, will affect the house’s drift. Forces exerted by earthquake ground motion are resisted by a house’s strength while the drift (deflection) is resisted by the house’s stiffness.

Properly braced drywall (gypsum wallboard) as a wall finish will add strength to wall structures. Wood structural panel (oriented strand board) will be even stronger for wall strength.

Drywall (gypsum wallboard):
drywall.jpg

Wood structural panel (oriented strand board):
strand-board.jpg

Load Bearing Walls & Pillars

Pillars and other building structures that are load bearing, such as upper level floors, need adequate reinforcement so not only are they stronger, but so they can handle fluctuations that may be caused by tremors or shaking with entirely failing even if damaged.

A problematic example is this staircase column in Lombok:
faulty-support-column-300.jpg

A good example of column reinforcement done with rebar can be seen in this example below. While the brick walls may fall, the columns, at least, should remain standing and carry the weight of the roof above.

Reinforced Columns:
Reinforced-columns-400.jpg

A good resources to start with to learn more is U.S. FEMA Building Framing Systems and Best Practices Guide.

Non-load Bearing Walls

Non-load-bearing walls (nonstructural partitions) carry only their own weight. They are often used to close off a room inside a building (interior walls). They often add significantly to the strength provided by required bracing materials.

Shear Walls

We recommend a fully sheathed shear walls (solid walls) around doors and openings with wood structural panel (oriented strand board) and braces or hold down devices at each corner.

Shear wall using wood structural panel:
shear-wall.jpg

Wall Bracing

Wall bracing adds structural support and is particularly useful at corners and joints. A typical wall may rack if no bracing is provided. Sheathing (layers of boards applied to the studs) is a common method for bracing a wall. A good site for getting an overview for wall bracing is Botetourt County's Wind Bracing Guide.

bracing.jpg

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