A shear wall is a structural support element that resists shear forces, like heavy winds and seismic activity. In civil engineering, shear force refers to forces that act in a perpendicular fashion against structural members of a building (beams, columns, and so on), causing it to twist and bend.
Shear walls help keep buildings stable by transferring lateral loads to the foundation, preventing the structure from leaning or collapsing. While all shear walls serve the same purpose, the material they’re made of (like concrete, steel, and wood), thickness, length, and where they’re positioned can vary based on several factors in building construction and must conform to specific construction codes.
In this guide, we’ll go over how shear walls work, where you typically find them in buildings, and the different types of shear walls.
How Do Shear Walls Work?
When lateral forces, like high wind, severe weather, or earthquakes, put pressure on a building, shear walls absorb the force from weaker building elements, like exterior walls, floors, and roofs, and transfer it to the ground foundation. The lateral strength shear walls provide prevents buildings from swaying or falling.
Shear walls serve a similar purpose to load-bearing walls — both absorb and transfer the force and pressure of a load from its source to the ground foundation. Instead of absorbing vertical loads and holding a building up as load-bearing walls do, shear walls keep it from collapsing sideways by resisting horizontal forces.
Shear wall design can depend on several factors, including the needed shear capacity and requirements for deflection calculations (how much the structure changes when force is applied.
A typical wood shear wall follows a specific code. The APA guidelines can help you understand how best to meet code requirements when putting together the three elements that create a shear panel:
- Framing: To resist lateral pressure, shear walls are built with a movement-resisting wood frame that consists of two or more walls. The walls are joined by slabs or beams, and the beams are rigidly connected to the columns to ensure stability.
- Fasteners and other hardware: Components like fasteners, hold-downs, and studs connect the parts of a shear wall, keeping crucial elements, like the sheathing, in place.
- Sheathing: Sheathing creates a structural panel, reinforcing a shear wall so that it doesn’t collapse on itself. This layer is typically plywood or oriented strand board (OSB).
Common Shear Wall Materials
A shear wall can be made from a variety of materials, but the most common ones are concrete, steel, and plywood.
- Concrete: Reinforced concrete is used in shear wall construction to provide more lateral strength and rigidity. These concrete walls are most commonly used for medium to high-rise buildings (from four to 35 stories high).
- Steel: Steel plate shear walls are constructed with steel and infill plates. They’re most often used in tall buildings for seismic resistance and are designed with boundary elements that bear seismic loads during events like earthquakes.
- Plywood: Plywood shear walls are made of wood and are designed to resist ongoing lateral forces from wind loads, like hurricanes, tornadoes, and high winds.
Exterior vs. Interior Shear Walls
Depending on the needs of a structure, it might have exterior or interior shear walls, or both.
Exterior shear walls are much more common and found in almost all houses for structural support. Interior shear walls are typically only found in larger structures, like big houses or high-rise buildings, that are more vulnerable to collapse. The taller a building is, the more need it has for a structural system that resists lateral forces.
Where Are Shear Walls Located in Buildings?
Shear walls work best when they’re placed symmetrically within, or around, a building’s central axis point. If there’s a shear wall on the north side of a building, there has to be an identical one on the south side to create symmetry.
The spacing of shear walls in a building depends on factors like building size and if the walls are exterior or interior.
Center of Each Half of the Building
Interior shear walls are typically placed at the center of each half of a building. This helps larger buildings, like bigger houses, high-rise buildings, and skyscrapers, withstand seismic forces better. For these structures, interior shear walls can come in the form of core walls or box-shaped columns, placed in areas like the stairwell or elevator.
The Ends of the Building
Exterior shear walls are usually located on the ends of a building. Having one shear wall on each end creates the symmetry necessary to make the building movement-resistant.
From houses to skyscrapers to commercial buildings, almost every type of structure we encounter in our daily lives uses shear walls to stay stable and keep us safe. By protecting us from powerful lateral forces, shear walls keep our homes and communities standing in the event of severe weather like earthquakes and storms.