Shear wall design is governed by the International Residential Code and International Building Code in various jurisdictions.
High-rise structures susceptible to lateral wind and seismic stresses frequently use shear walls.
The impacts of wind forces become more important as a structure’s height grows in reinforced concrete framed constructions.
What is Shear Wall?
A shear wall is a vertical structural engineering component designed to resist in-plane lateral forces, which are frequently brought on by wind and seismic loads.
A shear wall resists loads parallel to the wall’s plane.
The diaphragm shear is transferred to shear walls and other vertical components of the seismic force-resisting system via collectors also referred to as drag members.
Shear walls are often made of steel plates, reinforced concrete, reinforced masonry, or light-framed or braced hardwood walls with shear panels.
How do Shear Walls Work?
Shear walls operate in a manner that can be easily understood by picturing a wooden square with four edges, which is effectively two columns and two beams.
It might be necessary to have structural engineering knowledge to fully comprehend the physics of shear walls.
This frame may hold the weight from above because any pressure applied to the top beam is transmitted via the columns to the base of the square (compression).
But if you apply too much lateral force to the square’s sides, it will twist and collapse in on itself unless it is supported.
The braces on shear walls prevent them from collapsing in on themselves, they prevent the wind from destroying your home.
The support given by shear walls creates a design challenge for architects.
Depending on whether the sheathing covering the frame or other bracing inside it provides support against lateral loads, any windows or doors must be restricted in size relative to the overall area of the shear wall.
Types of Shear Wall:
1. Reinforced concrete shear wall:
For residential constructions, reinforced concrete shear walls are frequently employed.
There is reinforcement for both the vertical and horizontal orientations.
Bars are evenly spaced and fastened at each wall’s end.
As a result, the end zones of RC shear walls are sometimes known as boundary elements or barbells.
The wall thickness of an RC shear wall can vary based on a variety of criteria including the building’s need for thermal insulation, its age, etc.
It ranges from 140 to 500 millimetres.
Shear walls are typically present continuously throughout a building’s height.
However, occasionally it is stopped when there is a building entry, a parking area, etc.
2. Concrete Block shear wall:
Shear walls made of concrete blocks are constructed using hollow concrete blocks and steel reinforcement bars.
Typically, reinforcing is used to improve the resistance of concrete block masonry to seismic loads.
Retaining rods are positioned vertically and horizontally through the cracks between the concrete blocks.
Fresh concrete grout is poured into the hollow space left by the placement of bars in concrete block masonry after it has had time to dry.
This kind of wall can support lateral and gravity loads.
As a result, they can serve as both shear and load-bearing walls.
3. Steel Shear Wall:
A steel shear wall is constructed from a steel plate wall, a floor beam, and a boundary column.
More resembling plate girders in behaviour are steel shear walls.
Boundary columns serve as flanges, horizontal beams as stiffeners, and steel plate walls as the web of the plate girder.
4. Plywood Shear Wall:
Traditional walls known as timber shear walls are made of plywood.
It is made up of studs and plywood sheets.
Plywood sheets carry the shear load while studs resist tension or compression.
Plywood shear walls are currently being modified utilizing modern technology.
Steel sheets, boards, and other materials are utilized in place of plywood.
5. Mid-Ply Shear Wall:
The mid-ply shear wall is a superior alternative to the typical plywood shear wall.
In this case, a central plywood sheet is added to a typical plywood wall, and a series of stud pairs are positioned on either side of the middle plywood sheet.
The outside plywood sheets are attached to the middle ply via studs.
Here, plywood shear walls have studs that are 90 degrees out of alignment with them.
The issues with ordinary shear walls are resolved by mid-ply shear walls, which also have a larger lateral load-carrying capacity.
Typical shear wall shapes:
Even though many shear walls are just rectangular planes, they can be constructed in a variety of shapes to increase their ability to withstand wind and earthquakes.
A building’s elevators and mechanical systems are often located in the central core, which is surrounded by box-shaped core walls that form a square or rectangle.
Short extensions are attached to the ends of the main plane of C-shaped walls.
L-shaped walls feature one end of the plane that is longer than the other.
The letters T, U, and W are arranged after the letters they essentially resemble.
The structural engineer will decide which form is ideal to utilize in any given circumstance.
Some shapes are better at absorbing seismic effects, while others are better suited to strong winds.
5 Tips for Installing Shear Walls:
A few easy guidelines can ensure success when putting shear walls in a home.
Sheathing (usually made of plywood or OSB) is fastened to frames in the majority of American homes.
- Examine the panel stamp on the material to confirm that the OSB or plywood is approved for sheathing and DOC product standard meets with building regulations.
- Choose panels that are appropriate for your specific sheathing project (they are available in lengths up to 12 feet).
- There will be less blocking needed for the longer panel.
- A strength axis runs the length of each panel.
- Although putting panels horizontally may result in increased wind resistance, installing them vertically needs less work.
- However, some authorities including the Engineered Wood Association, resist that horizontal and vertical installations are equally successful.
- The sheathing is fastened to the frame with nails.
- The designer’s or engineer’s designs will specify their size and spacing.
- The foundation walls and sheathing must be mechanically connected using metal connectors (these will also be specified in the plans).
What Kinds of Construction require Shear Walls?
The majority of houses have external shear walls, while inside shear walls are often larger homes and high-rise structures that are exposed to lateral winds and seismic stresses.
As a building’s height rises, internal shear walls and a lateral force-resisting system become more crucial.
Location of shear walls:
Shear walls are generally best placed in the middle of each half of a building including high-rise structures and homes that need them.
Beyond that, symmetrical shear walls must be constructed around the central axis of the building.
To put it another way, if a shear wall exists on the north side of anything, then the same must exist on the south side.
If a building has a shear wall at its southeast corner, another wall will be built in its southwest corner on the other side of the building’s centre axis.
Identifying shear walls on plans:
Oftentimes, a thinner line denotes the sheathing that will cover a shear wall that is marked on a plan with a solid line (and which is usually then specified in a separate sheathing schedule).
FAQ- Shear Wall:
Q1. What is the function of a shear wall?
A shear wall is designed and constructed to withstand racking from pressures like the wind.
It can be made of masonry, concrete, cold-formed steel, or wood.
Shear barriers significantly reduce a building’s sway to protect the structure and its contents.
Q2. How can a shear wall be identified?
On a plan, a thinner line often follows a solid line designating a shear wall to indicate the sheathing that will cover it (and which is usually then specified in a separate sheathing schedule).
One of the various building elements that may be seen on architectural blueprints is shear walls.
Q3. Do homes require shear walls?
Exterior shear walls are necessary for most houses and buildings in high-wind and earthquake-prone areas.
However, interior shear walls are also necessary for high-rise buildings and bigger homes to safeguard against lateral wind and seismic stresses.
Conclusion:
The most effective building component for mitigating the effects of lateral pressures brought by an earthquake is the shear wall.
It can withstand lateral stresses brought by strong winds, earthquakes, and other environmental variables.
This wall construction will make the buildings overly stiff, which will harm the structure.
Shear walls are most useful for housing huge populations in small-area constructions.
The shear walls are the foundation of the construction sector in emerging nations.
