An interior braced wall is a specific type of wall panel within a structure designed to resist lateral forces, such as those caused by earthquakes, where this resistance is primarily provided by the interior finish materials.
Understanding Braced Walls
To grasp what an interior braced wall is, it's helpful to first understand the concept of a braced wall panel. According to building codes and structural design principles:
- Braced wall panels are portions of walls where exterior sheathing or interior finish is designed and installed to provide the required resistance to lateral loads due to earthquakes.
Lateral loads are forces that push horizontally against a building. During an earthquake, the ground shakes, creating acceleration that translates into significant lateral forces on the structure. Braced wall panels are crucial elements specifically engineered to counteract these forces and help prevent a building from collapsing.
How Braced Walls Work
Braced walls provide stability by resisting the racking or deformation (leaning) that lateral forces try to induce. They achieve this by acting as shear walls, transferring the horizontal forces from the floor and roof down to the foundation. This resistance is typically provided by the structural sheathing or finish material fastened to the wall framing.
Interior vs. Exterior Braced Walls
Based on the definition of a braced wall panel, the difference between an exterior and an interior braced wall lies in which part of the wall provides the bracing:
- Exterior Braced Wall: This type of braced wall panel relies on the exterior sheathing (like plywood, OSB, or structural fiberboard) to provide the necessary lateral load resistance.
- Interior Braced Wall: This is where the interior finish material is specifically designed and installed to act as the bracing element.
Therefore, an interior braced wall panel is a section of an interior or exterior wall (even an exterior wall can be braced from the inside) where the structural capacity to resist lateral forces comes from the finish material on the interior side.
Examples of Interior Finish Bracing
While exterior sheathing is very common for bracing, certain interior finishes can also serve this purpose if specified and installed according to engineered designs or prescriptive code requirements. Examples might include:
- Gypsum Wallboard (Drywall): Specially installed and fastened gypsum board can contribute to or provide bracing capacity, particularly in certain construction types and seismic zones.
- Wood Structural Panel Finish: In some cases, wood structural panels (like plywood or OSB) might be used on the interior side as the finished surface and also serve as the bracing element.
Choosing between interior and exterior bracing depends on various factors, including architectural design, wall type, required bracing capacity, and local building code provisions.
In summary, an interior braced wall is a critical structural component where the interior finish materials are the primary means of resisting the horizontal forces exerted during events like earthquakes, contributing to the overall stability and safety of the building.
