In recent years, with increasing awareness of building safety, special attention has been given to non-structural components and how to restrain them. One of the most important of these components is walls, which, if not properly restrained, can cause irreparable damage during earthquakes or lateral forces. Wall Post serves as an engineering solution, playing a very important role in maintaining wall stability and increasing building safety. In this article, we intend to comprehensively and professionally examine what a wall post is, what its applications are, why its use is essential, and what points should be observed in its design and execution.
A wall post is a member or element used for restraining non-structural walls in a building. Non-structural walls, such as brick, clay, or block walls, do not directly play a role in bearing the main loads of the building, but they are highly vulnerable to lateral forces. A wall post prevents movement, buckling, cracking, and collapse of these walls by connecting them to the main building frame.
Simply put, a wall post acts as a reliable support for walls so that in critical conditions such as earthquakes, the wall does not separate from the structural frame and collapse.
The importance of wall posts is not limited to a mere construction recommendation, but is a technical and safety necessity. The most important reasons for using wall posts are:
During an earthquake, the building is subjected to intense horizontal forces. If walls are not properly restrained, these forces can cause the wall to separate from the structure, develop deep cracks, and even collapse completely. Wall posts control these forces by creating a proper connection between the wall and the frame, preventing stress concentration in the wall. For this reason, proper execution of wall posts has a direct impact on occupant safety.
Wall posts are divided into different types based on location, execution method, and type of structure:
This type of wall post is installed vertically on both sides of the wall or at specified intervals, and its main function is to restrain the wall along its height. Vertical wall posts are typically required for tall walls or walls with significant length.
Horizontal wall posts are installed along the length of the wall, usually at the mid-height level or under the ceiling. This type of wall post prevents deformation and buckling of the wall, increasing its stability.
The most common type of wall post, made from steel sections such as angles, channels, or profiles. This type has wide application due to its high strength, quick installation, and proper connection capability to the structure.
In some projects, wall posts are executed as reinforced concrete. This method is usually used in concrete buildings or for specific walls.
Wall post installation must be carried out in accordance with technical standards and construction drawings. The general steps for wall post installation include:
Incorrect installation can severely reduce the effectiveness of wall posts, so engineering supervision at this stage is very important.
The spacing of wall posts depends on factors such as wall type, wall height, and structural conditions. Typically, for tall walls, wall posts must be installed at regular intervals to prevent wall instability. Adhering to these criteria will result in better wall performance against lateral forces.
One common mistake is considering wall posts and braces as the same thing. While:
Therefore, these two elements have different functions and are not interchangeable.
One common problem in buildings is the formation of horizontal and vertical cracks in walls. These cracks are usually caused by structural settlement, temperature changes, or lateral forces. Wall posts play an important role in reducing and controlling these cracks by properly restraining the wall and evenly distributing stresses. In fact, the presence of wall posts ensures that the wall behaves more uniformly and that stress does not concentrate at one specific point.
Installing wall posts alone is not sufficient; it must be done alongside proper wall construction. The type of mortar, the arrangement of blocks or bricks, maintaining the separation joint, and using appropriate materials in connecting the wall to the wall post are all effective in the final performance. If the wall is rigidly connected to the wall post, additional stresses may be imposed on the wall during an earthquake; for this reason, connections that allow controlled relative movement are typically used.
Buildings in which wall posts are properly installed face fewer wall-related problems over time. Reduced cracking, prevention of wall separation from the ceiling or columns, and preserving wall appearance are among the long-term benefits of wall post installation. This leads to lower maintenance and repair costs during the building’s operational years.
Despite the high importance of wall posts, some installation mistakes are observed in certain projects that reduce their effectiveness. These mistakes include:
Recognizing and avoiding these errors plays an important role in increasing building safety.
Contrary to some people’s assumptions, wall posts are not only for exterior walls. Interior walls also require wall posts if they have significant length, height, or are in the path of lateral forces. In exterior walls, wall posts have a double role because, in addition to earthquake forces, wind forces also act on the wall.
Experience from construction projects has shown that buildings with properly installed wall posts have sustained significantly less damage in natural disasters. In contrast, omitting wall posts typically leads to extensive cracking, wall collapse, and increased damages. This comparison clearly demonstrates the importance of this simple yet vital component.
According to Appendix Six of Standard 2800, proper installation of wall posts plays a very important role in increasing the safety of non-structural walls against earthquakes. In this section, the most important executive regulations for wall posts in interior and exterior walls of buildings are thoroughly examined.
If the wall length exceeds the allowable design limit (maximum 4 meters), the use of a vertical steel or concrete restraint member is mandatory. This restraint is responsible for restraining the wall against out-of-plane forces.
The connection of the restraint to the floor structure must be pinned.
The connection of the restraint under the ceiling must be sliding and in the plane of the wall to allow relative movement of the wall.
In exterior walls, the surface of the restraint must be covered with moisture-resistant rock wool, over which fiber mesh or expanded metal lath should be applied to prevent cracking of the finishing layer.
Load transfer from the wall to the restraint is only permitted through welded or bolted connections, and the use of friction resistance from gravity loads is prohibited.
Welding the restraint to beam angles that are only intended for out-of-plane restraint is not permitted.
Due to the sliding connection of the restraint, there is no need to maintain a separation gap between the wall and the restraint, and the wall can be built directly adjacent to it.
For walls outside the frame, the restraints at both ends of the wall must be restrained against lateral movement in both directions using telescopic connections.
In this case, a separation gap equal to 1% of the floor height between the wall and the restraint must be observed.
For walls with a height exceeding 3.5 meters, the use of a horizontal steel or concrete restraint is mandatory to reduce the free height of the wall.
The horizontal restraint must be fully placed on top of the wall.
The gravity load of the wall above must not be transferred to the horizontal restraint.
For proper execution of this system, the use of end restraints is necessary to support the horizontal restraint.
The connection of non-structural walls to columns, shear walls, or other vertical members must be carried out in a way that does not prevent the relative movement of the wall during an earthquake.
Permitted connection methods include:
Sliding connection using intermittent or continuous angles or channels
Using U-shaped sliding connections
If using bed reinforcement bars, their end anchors can be used for out-of-plane restraint, eliminating the need for angles or channels.
The wall-to-ceiling connection must be:
Sliding
Without direct connection of the wall to the ceiling
And executed using out-of-plane restraint such as angles or channels.
In some cases, the last row of the wall can be reinforced with bed reinforcement bars or ties. This method is particularly applicable for interior walls with joist or composite ceilings.
For connecting intersecting walls, due to the possibility of in-plane tensile stress, it is recommended to:
Use metal ties similar to column connections
Or separate the walls at the intersection using a restraint member
For openings larger than 2.5 meters, the installation of restraints and lintels is mandatory.
For smaller openings, if using proper metal frames and connecting the wall reinforcing elements to the frame, restraints are not required.
Otherwise, installing a restraint adjacent to the opening will be required.
In bays with bracing:
The wall must be separated from the structural frame in the plane direction
Any contact or connection of the wall with the bracing is prohibited
The wall must be constructed outside the bracing axis, in accordance with the details of Appendix Six of Standard 2800
If covering the bracing is required, two independent walls on either side of the bracing can be used without any connection to it.
According to Appendix Six of Standard 2800, in hospital buildings, to prevent wall cracking and maintain the performance of sterile spaces:
Adjacent to beams and columns, continuous channels must be used
The space inside the channel shall be filled with 1% of the floor height of compressible material such as moisture-resistant rock wool
These regulations are mandatory for block and panel walls.
According to the regulations of the Fire Department:
The minimum recommended parapet height is 1.2 meters
Perimeter columns on the roof should preferably extend to a height of 1.35 meters
In the space between columns:
By installing restraints, the free length of the wall should be reduced
The parapet wall should be reinforced according to Appendix Six of Standard 2800 and Regulation 714
Alternative method:
Using restraining bars connected to the roof slab (concrete restraint) at intervals of no more than 1 meter.
According to clause 1-5-8 of Appendix Six of Standard 2800:
Interior and facade walls must be constructed so that they do not impede the movement of structural components during an earthquake.
If the wall is not separated from the frame, the interaction effect between the wall and the structure must be considered in analysis and design.
Infill wall refers to a wall that fills an entire bay of a concrete or steel frame and is surrounded by beams and columns. The frame-infill assembly must fully meet the requirements of Appendix Six of Standard 2800.
Wall posts are one of the most important non-structural components in buildings, playing a vital role in increasing the safety and stability of walls. Paying attention to proper design and principled installation of wall posts can prevent heavy losses in natural disasters. If safety, durability, and construction quality are important to you, installing wall posts should be considered a fundamental principle.
If you are looking for standard and reliable wall posts for your construction projects, Khesht-e Sabz Company, offering a variety of vertical and horizontal wall posts, is ready to meet your needs throughout Iran. High build quality, product variety, and fast delivery have made Khesht-e Sabz a trusted choice for engineers and builders.
Contact Us:
09128115548
[accordion title=”FAQs”]
[accordion-item title=”1. What is a wall post?”]
A wall post is a restraining member used to increase the stability of non-structural walls in a building, preventing wall collapse or cracking against lateral forces such as earthquakes and wind.
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[accordion-item title=”2. Why is the use of wall posts in buildings essential?”]
Because non-structural walls are vulnerable to lateral forces, and wall posts significantly increase the life and property safety of the building by restraining these walls.
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[accordion-item title=”3. In which walls should wall posts be installed?”]
Wall posts must be installed in both interior and exterior walls, especially tall or long walls and walls located outside the structural frame.
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[accordion-item title=”4. What are the types of wall posts?”]
Wall posts are generally divided into two types: vertical wall posts and horizontal wall posts, each responsible for restraining the wall in a specific direction.
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[accordion-item title=”5. What is the standard spacing of wall posts?”]
The spacing of wall posts depends on the wall type, height, and structural conditions, but typically, walls with a length exceeding 4 meters require wall posts.
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[accordion-item title=”6. What is the difference between a wall post and a brace (Klaf)?”]
Wall posts are used to restrain non-structural walls, whereas braces (Klaf) are part of the building’s load-bearing system and are responsible for carrying structural loads.
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[accordion-item title=”7. How is the connection of the wall post to the structure made?”]
The connection of the wall post must allow relative in-plane movement of the wall and is typically executed as a pinned or sliding connection.
[/accordion-item]
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