What are Steel Shear Walls?

Steel shear walls are shear walls made out of steel plates, which will also name it as steel plate shear walls (SPSW). Similar to the conventional concrete shear walls, SPSW also serves the function to resist horizontal shear force and overturning moment due to lateral loads. 

Steel shear walls are less commonly used than concrete shear walls for resisting lateral loads. However, when employed, they offer distinct advantages over their concrete counterparts.

Let's dive into the details on why steel shear walls are popular in building design and construction, along with their essential design features. 

Also Read: What are Shear Walls?

Steel Plate Shear Walls (SPSW)

Structurally, a steel plate shear wall consists of a steel plate wall, two boundary columns and one horizontal floor beam as shown in Figure-2. Together, the arrangement act as a vertical plate girder, where the columns act as the flanges of the vertical plate girder and the steel plate act as its web. At each building floor, a horizontal floor beam is provided, which would act as transverse stiffeners in a plate girder. 

Fig.2. Typical Steel Plate Shear Wall System (SPSW)

SPSW has been researched and applied since 1970s. They have been used as lateral load resisting system for new buildings at the time, in highly seismic regions in California and Japan. 

Types of Steel Plate Shear Walls

There are three types of SPSW systems:

1. Un-Stiffened SPSW or Thin SPSW
2. Stiffened SPSW 
3. Composite Concrete SPSW

Here's a breakdown of the three main types:

 
1. Un-Stiffened SPSW or Thin SPSW: This is the simplest form of SPSW, consisting of a thin steel plate connected to the building's structural frame. Due to their thinness, they have limited shear strength and may require additional bracing or stiffening elements.

Fig.3. Stiffened and Unstiffened Shear Walls

2. Stiffened SPSW: These walls include stiffeners, such as beams or columns, attached to the steel plate to increase its shear capacity. Stiffeners provide additional support and rigidity, making these walls more effective in resisting lateral loads.

3. Composite Concrete SPSW: These walls combine steel plates with concrete elements, creating a composite structure. The combination of steel's strength and concrete's mass provides a high shear capacity and excellent seismic performance. Composite walls often exhibit good ductility, which is desirable in earthquake-prone regions.

Fig.4. Composite Concrete Steel Plate Shear Walls

Also Read: Types of Shear Walls in Construction

Advantages of Steel Plate Shear Walls

• A properly design SPSW system is highly ductile and possess relatively large energy dissipation capability. This makes efficient and economical shear wall systems. 
• The initial stiffness of steel shear walls are relatively high and hence effective in limiting the story drift. 
• Compared to R.C.C shear walls, SPSW systems are light in weight. This helps reduce mass of the structure hence the overall seismic load.
• Shop-welded, field-bolted steel shear walls: Faster construction, lower costs, and better quality control.
• Steel plate shear walls: Thinner than concrete walls, saving space in high-rise buildings.
• Seismic retrofit: Easier and faster construction with steel plate shear walls.
• Shop-welded, field-bolted systems: More efficient, especially in cold climates.

Major Failure Modes of Steel Plate Shear Walls

Steel plate shear walls can fail in various ways. These failures can be categorized based on the component affected:

Wall Plate Failures

• Slippage of bolts: The bolts connecting the wall plate to the columns and beams can slip.
• Buckling or yielding of the steel plate: The wall plate itself can buckle or yield due to excessive loads.
• Fracture of the wall plate or its connections: The wall plate or its connections to the boundary elements can fracture.

Beam Failures

• Shear yielding or plastic hinge formation: The top and bottom beams can yield or form plastic hinges.
• Local or overall buckling: The beams can buckle locally or overall.
• Fracture of connections: The connections between the beams and other components can fracture.

Column Failures

• Plastic hinge formation: The boundary columns can form plastic hinges at their top or bottom.
• Local or overall buckling: The columns can buckle locally or overall.
• Fracture of connections: The connections between the columns and other components can fracture.
• Failure of foundations: The foundations supporting the wall can fail.

Note: The ductility or brittleness of these failures depends on factors such as the material properties, geometry, and loading conditions.

Disadvantages of Steel Shear Walls

While steel shear walls offer several advantages, they also have some drawbacks:

• Cost: Steel shear walls can be more expensive to construct than other systems, especially in regions where steel is relatively expensive.
• Weight: Steel shear walls can add significant weight to a structure, which may require additional foundation design or structural reinforcement.
• Corrosion: Steel is susceptible to corrosion, especially in environments with high humidity or exposure to corrosive agents. This requires regular maintenance and protective measures.
• Limited flexibility: The design and placement of steel shear walls can be less flexible compared to other structural systems, as they often require specific placement and configuration to be effective.
• Potential for buckling: Steel shear walls can experience buckling under certain loading conditions, which can reduce their load-carrying capacity.
• Aesthetic limitations: Steel shear walls can be visually unappealing, especially if not carefully integrated into the overall architectural design.

Read More On: Steel Structures