Plastic Rebar Chairs: Construction with Stability

Selecting the right support for rebar is vital in concrete construction. Plastic rebar chairs are the go-to for many builders, valued for their stability and ease of use. This article demystifies why these chairs are integral to construction projects, exploring their role, benefits, and what to consider when choosing them.

Key Takeaways

Plastic rebar chairs are essential for maintaining the position and alignment of reinforcing bars in concrete structures, contributing to their strength, durability, and resistance to elements like moisture and chemicals.
Plastic rebar chairs offer advantages over metal chairs including corrosion resistance, ease of installation, and versatility to accommodate various rebar sizes and shapes, leading to long-term structural integrity and reduced maintenance costs.
Recent technological advancements in rebar support products have introduced features for enhanced performance and sustainability, and companies are increasingly using eco-friendly materials in the production of rebar chairs.

Exploring the Essentials: What Are Plastic Rebar Chairs?

Fundamentally, the plastic rebar chair is a simple yet innovative tool. As the name suggests, these chairs are made from plastic and are designed to hold rebar, specifically:

Hold reinforcing steel bars at the right position and elevation within a concrete structure
Maintain the reinforcing bars’ position during the concrete pouring stage
Significantly contribute to the structural stability and strength of the final concrete structure.

Plastic rebar chairs are not just about stability, though. They also provide the crucial function of:

maintaining the correct depth and alignment of the rebar
ensuring that the reinforcing bars are completely and uniformly encased in concrete
reinforcing the concrete
protecting the rebar from potential corrosion and damage
enhancing the longevity of the concrete structure.

Defining Plastic Rebar Chairs

Constructed from high-density polyethylene (HDPE) or similar plastics, plastic rebar chairs boast the following features:

Durability and corrosion resistance
Lightweight, making them easy to handle and install
Designed to firmly hold the rebar in place, even in the turbulent environment of concrete pouring.

The design of plastic rebar chairs and rebar stands embodies practical engineering. Each rebar chair is equipped with a structure that allows the rebar to snap into position and stay elevated above the ground during the entire concrete pouring process. Furthermore, these chairs are designed to accommodate various rebar sizes, making them versatile tools in any construction project.

The Role in Concrete Applications

The strength and stability of a concrete structure are largely reliant on the accurate placement and alignment of the rebar within it. Plastic rebar chairs play an instrumental role in achieving this alignment and maintaining it throughout the concrete pouring process. The chairs hold the rebar securely in place, ensuring that the bars remain at the right depth and configuration, thus reinforcing the overall integrity of the concrete structure.

The benefits of using plastic rebar chairs in concrete applications are not limited to their structural contributions. These chairs also contribute to the durability of the structure. Plastic rebar chairs are resistant to solvents, oils, and acids and leave no marks on the concrete after demoulding, helping to preserve the appearance of the structure. However, omitting these chairs can lead to concrete cracks and diminished stability, underscoring their importance in construction.

The Comparative Advantage of Plastic Over Metal

Traditionally, rebar chairs have been constructed from metal, typically steel. Plastic rebar chairs have proven to offer significant advantages compared to their metal counterparts. They are preferred for their:

Durability
Corrosion resistance
Longevity
Reduced maintenance costs

Moreover, plastic rebar chairs offer a simpler and more convenient installation process, eliminating the need for wire tying, which is often required when using metal rebar chairs.

For any material used in construction, being corrosion resistant is a key property, particularly in environments exposed to moisture and chemicals. Plastic rebar chairs, thanks to their non-corrosive nature, ensure strong and prolonged support and can significantly reduce maintenance costs compared to their metal counterparts.

Another advantage that demands attention is the ease of installation. Plastic rebar chairs can be fixed onto the reinforcement directly, simplifying the installation process significantly.

Corrosion Resistance and Longevity

The materials used in their construction give plastic rebar chairs their corrosion resistance. Industrial-grade polypropylene, a material that does not rust or corrode in concrete environments, is commonly used in their manufacture. This gives plastic rebar chairs’ corrosion resistant a significant advantage over metal rebar chairs, especially in environments with moisture and chemical exposure.

The corrosion resistance of plastic rebar chairs offers several benefits:

Guarantees the longevity of the chairs
Renders them a cost-effective choice over time
Average lifespan ranging from 10 to 20 years
Sound investment for any construction project
Do not suffer from rust or degradation commonly seen in metal chairs

Installation Ease and Weight Considerations

A striking advantage of plastic rebar chairs is their straightforward installation process. These chairs offer a notably easier installation process compared to their metal counterparts, thanks to their lightweight nature, compact size, and the ability to be directly fixed onto the reinforcement without the need for binding.

The average plastic rebar chair offers several advantages over its metal counterpart:

It is lighter, reducing the overall load and improving handling during construction.
Despite its lighter weight, it maintains stability and has a high load capacity.
It has high tensile and compressive strength, ensuring reliable support and safety within the concrete structure.

Suitability Across Rebar Sizes and Shapes

Versatility is a standout feature of plastic rebar chairs. These chairs are designed to accommodate common rebar sizes ranging from #3 to #5, providing consistent support across a variety of construction projects. Besides, the chairs’ resilient plastic composition and their ability to attach directly to the reinforcement without requiring binding enhance their ease of use and adaptability to different rebar dimensions.

Plastic rebar chairs are not a one-size-fits-all solution. These chairs offer sturdy support by securely holding the rebar in place during construction, ensuring precise positioning within the concrete. They are designed to leave no residue or marks on the concrete upon demolding, making them ideal for use in a wide range of concrete applications. However, there may be limitations on the sizes and shapes of rebar that plastic chairs can support, and certain situations may call for alternative solutions.

Compatibility With Common Rebar Sizes

The compatibility of plastic rebar chairs with common rebar sizes is a crucial factor in their widespread use in the construction industry. Plastic rebar chairs are engineered to support typical rebar dimensions utilized in construction projects, including #3, #4, and #5, providing stable support for these dimensions during construction.

The versatility of plastic rebar chairs extends beyond their ability to accommodate different rebar sizes and many shapes. These chairs feature a range of design enhancements, such as:

Bayonet connections for stable support
Dual direction capabilities with locking clips to prevent shifting
Additional rings for enhanced strength and stability for larger sizes

These features make plastic rebar chairs a reliable choice for various construction needs.

Adapting to Different Rebar Configurations

Plastic rebar chairs are adaptable tools that can accommodate various rebar configurations, making them suitable for diverse construction projects, including bridge decks. They can be securely positioned on the reinforcement using cards and sleeves, eliminating the need for binding. This adaptability makes them an excellent choice for projects on bridges where different rebar configurations are often required.

There are several types of rebar chairs tailored for different rebar configurations. These include standard rebar chairs, continuous bar support, and support chairs, among others. Each of these types offers unique advantages, such as increased concrete resistance to failure and improved safety, making them invaluable tools for maintaining the correct rebar positions during construction.

Best Practices for Using Plastic Rebar Chairs

Certain best practices can ensure optimal results when using plastic rebar chairs. For instance, it’s important to position the chairs correctly, suspending the rebar off the ground to ensure it’s fully embedded in the concrete. The spacing between the chairs is also crucial. Typically, rebar chairs should be positioned approximately 2 to 3 feet apart along the length of the rebar, although in certain situations, larger spacing may be necessary to ensure stability.

It’s important to verify the stability of the rebar chairs before pouring the concrete. This can be done by placing the chairs in a crisscross grid pattern and locking them together with the rebar. However, it’s important to avoid common mistakes such as setting the rebar supports too far apart and failing to secure the rebar on the supports properly before pouring the concrete.

Placement and Spacing Tips

The appropriate placement of plastic rebar chairs is critical for ensuring optimal reinforcement in a concrete structure. The chairs should be used to support reinforcing steel mats and maintain the steel at the appropriate elevation in the slab. As for the spacing between the chairs, the typical practice is to position them approximately 2 to 3 feet apart. However, the specific spacing may vary depending on various factors, such as project requirements, plastic rebar chair dimensions, and load demands.

The proper placement and spacing of rebar chairs are crucial for providing support to the reinforcing bars and ensuring the correct concrete cover. Both of these factors contribute significantly to maintaining the stability of the structure. By following these placement and spacing tips, you can ensure that your rebar chairs are effectively supporting your reinforcement bars, leading to a stronger and more durable concrete structure.

Ensuring Stability Before Pouring Concrete

Before you start pouring concrete, it’s important to ensure the stability of the rebar chairs. One way to do this is by using rebar chairs and various support systems to guarantee their stability. The stability of the chairs can also be evaluated by considering factors such as their load capacity, the design features that enhance stability, and the use of durable plastic materials for heavy load support.

However, it’s also important to be aware of the potential problems that can occur if the rebar chairs are unstable. Unstable chairs can negatively impact the structure of the concrete, leading to weakened concrete, decreased flexibility, and the formation of superficial cracks at different depths. If the chairs are identified as unstable, it’s essential to address the issue promptly, possibly by replacing the chairs or using other solutions to ensure the stability of the rebar.

Quantity and Selection: How Many Rebar Chairs Needed?

While planning a construction project, calculating the required quantity of rebar chairs based on their load capacity and the amount of rebar in the slab is vital. For a 6m x 2.4m mesh sheet, for example, a minimum quantity of 22 bar chairs are necessary. However, the specific number of chairs needed may differ depending on various factors, including project requirements, rebar dimensions, and load demands.

Beyond quantity, choosing the appropriate type of rebar chair is also imperative. There are various options for rebar chairs, including snap chairs, support chairs with and without a base, and mesh chairs, among others. Selecting the right type depends on project needs. Consider factors like rebar configuration and weight capacity.

Calculating Quantity Based on Project Size

The quantity of rebar chairs needed for a construction project is directly influenced by the size of the project. Larger projects will require more chairs to adequately support the rebar within the concrete structure. To calculate the number of chairs required, it’s essential to first calculate the overall area of the slab and then apply standard spacing guidelines for rebar.

Several factors should be considered when calculating the quantity of rebar chairs needed, including:

The composition of the concrete
Chloride concentration
Rebar bond strength and size
The specific application of the rebar chair
The buckling capacity of the rebar

By taking all these factors into account, you can ensure that you have the right quantity of rebar chairs for your project and access the necessary rebar chair support.

Selecting the Right Type for Your Needs

Choosing the right type of rebar chair for your needs can be a complex task. There are many factors to consider, including the size and grade of the rebar, load-bearing requirements, and the desired concrete cover. To ensure the correct concrete cover and support, it’s important to choose a rebar chair size that fits the size and configuration of the rebar, usually accommodating sizes up to #3 bars.

There are also various types of rebar chairs designed for different applications. These include standard chairs, continuous bar supports, and support chairs, among others, that can be used for both indoor and outdoor projects. These chairs commonly provide elevation for rebar in various flatwork, such as slabs and foundations, making them a versatile option for a wide range of construction needs.

Innovations in Rebar Support Products

Just like many other industries, the construction industry is also being reshaped by advancements in technology. Recent innovations in rebar support products have introduced features aimed at enhancing performance and functionality. Some of these features include:

A one-piece design with a rebar retention clip and a beam
A 4” round base for stability
Adjustable height
Versatility to cater to diverse applications

One example of such an innovative product is the PPC Plastic On-Grade Chair. These advancements in rebar support products are revolutionizing the construction industry and making construction processes more efficient and effective by following best practices.

The shift towards sustainability has spurred the development of eco-friendly alternatives for rebar support. Some of these materials include:

Bamboo rebar
Stainless steel concrete reinforcement
Glass fiber reinforced polymer (GFRP) rebar
Basalt fiber reinforced polymer (BFRP) rebar
Plastic fiber

These materials are currently being explored as potential sustainable options for rebar support.

Enhanced Features for Improved Performance

The latest advancements in rebar chair design have introduced a range of innovative features aimed at improving performance. For instance, plastic rebar holders have gained popularity due to their convenience and effectiveness. Notable examples of pioneering designs include the PEZ Aztec® E-Z Chair® and the PPC Plastic On-Grade Chair. These chairs feature rebar retention clips and round bases. They support single mat or bottom layer double mat rebar configurations. They meet the needs of modern construction projects.

These new features significantly enhance the functionality of plastic rebar chairs. For example, the ability to fix reinforcement without binding strengthens concrete structures by enhancing load distribution and increasing resistance to structural failures. Furthermore, advancements have resulted in the creation of durable, lightweight plastic rebar supports with exceptional chemical resistance, enhancing the longevity and reliability of the concrete structures they are utilized in.

Sustainable Options in Rebar Support

The construction industry is increasingly focusing on sustainability, and rebar support is no exception. Utilizing sustainable rebar support in construction provides numerous advantages such as waste reduction, enhanced longevity of structures, and additional support to withstand heavier loads. Additionally, companies are using recycled materials in the production of plastic rebar chairs, thereby reducing the consumption of new resources.

Currently, environmentally friendly alternatives for rebar chairs are available in the market. Some options are crafted from polyethylene terephthalate (PET) bottles. These sustainable alternatives are not only eco-friendly but also contribute to cost savings, making them a win-win solution for the environment and the construction industry.

Summary

In conclusion, plastic rebar chairs are an essential tool in the world of construction, providing crucial support for reinforcing steel bars in concrete applications. They offer numerous advantages over their metal counterparts, including corrosion resistance, ease of installation, versatility, and compatibility with common rebar sizes. Plastic rebar chairs are evolving with new designs and features. They offer enhanced performance and sustainability. This contributes to eco-friendly construction practices.

As you embark on your next construction project, consider the benefits of plastic rebar chairs. They not only improve the structural integrity and longevity of your concrete structures but also contribute to a more sustainable future in construction. Remember, every great structure stands tall on the shoulders of these humble supports.

Certified MTP offers a full line of Rebar Chairs, Concrete Rebar Chairs With Base, Concrete Rebar Chairs Without Base, Rebar Mesh Chair Supports, Tilt-Up Rebar Chairs, Rebar Safety Caps, Rebar Spacer Wheels, and Ground Penetrating Radar (GPR) for Concrete, Concrete Test Hammers, Concrete Corrosion Testing for Concrete, and Concrete Crack Monitoring. The rebar detection and location equipment is available for fast and free shipping.

Frequently Asked Questions

Do rebar chairs stay in the concrete?

Yes, rebar chairs are designed to stay in the poured concrete and hold the rebar at a specified height as the concrete is poured, ensuring it becomes fully embedded.

How often do you place a rebar chair?

Place a rebar chair at the center of every rebar crossing if the spacing is greater than 12 inches, and at every other crossing if the spacing is 12 inches or less. This ensures proper support for the rebar.

How many concrete chairs do I need?

You will need to divide the length of your slab’s perimeter beam by 1.2 and then multiply the number of waffle pods by 4 to calculate the total number of concrete chairs needed for your project. Plan accordingly to ensure the right amount is available.

Are rebar chairs necessary?

Yes, rebar chairs are necessary as they help keep the rebar in their correct positions during construction and hold the rebar in place as the concrete covers it completely. They are essential parts of the permanent structure.