Precast concrete beams (and slabs, planks, joints, etc.) are a construction technique used in all types of construction projects. These beams are usually created in an off-site location and then transported to the job site, where they are installed in place.
Using precast beams in an extensive construction project is incredibly efficient and economical, which means you get more for your dollar. NVC Precast has been working with precast concrete beams for many years, and our team is very experienced at producing these products.
This blog will cover how precast concrete beams are made, the advantages and disadvantages of using them, and where you’ll commonly find these beams in buildings and other projects.
What is precast concrete?
Precast concrete is a method for creating concrete structures and elements. The name is derived from the fact these concrete elements are poured off the job site. Precast concrete can be prestressed or reinforced with steel and cables to increase its strength.
Types of precast concrete beams
When discussing precast concrete beams, there are several different types available. Beams are often used to support precast flooring, but they can also be used as flooring. Beams are often manufactured in a bespoke manner, designed for one particular project. Beams can be cast as reinforced or prestressed. The profiles you’ll commonly find in precast concrete beams include T-beams (and inverted T-beams), L-beams, U-beams, and rectangular beams.
T-beams (or Tee-beams) can be single or double, and they will cover the span range beyond hollow-core planks and other slab types. T-beams are one of the most efficient structural shapes. These beams are often cast with straight or deflected strands (as determined by design).
Inverted T-beams are often used in flooring systems where they’ll provide a ledger for precast flooring. These beams will have a structure similar to a single T-beam.
As their name suggests, L-beams will have an “L” shaped profile. These beams are commonly used where you need a ledge for precast flooring to sit on.
U-beams have a “U” shaped profile. These beams are used to span clear sections, and they can be pre-tensioned and reinforced. U-beams are commonly found in pedestrian bridges and are not often used with flooring systems.
Rectangular beams are solid rectangles in shape, and they are used to span clear sections. These names are reinforced and prestressed.
Why use precast concrete beams?
Precast concrete beams are made using a reusable mould. The moulds are made to the exact specification of each project, and then concrete is poured into the mould while housed in a climate-controlled area. After the concrete has cured, it is then transported to the job site to be installed. While the moulds are unique to each project, they can be used multiple times to reproduce the beams to a high standard.
Structural parts of a construction project can use precast concrete beams (along with walls, flooring, etc.). Creating a beam in this manner is highly cost-effective, reduces waste, increases quality assurance, and offers a safer environment for workers. The finish you get on a precast concrete beam is smoother and more attractive than other concrete pouring methods, making this process more desirable in public works with exposed beams.
How are precast concrete beams made?
All precast concrete beams are made off-site and then transported to a job site. These are the main stages that we’ll follow to make a beam.
Engineers use design tools to create plans to ensure the mould can deliver the desired concrete beam. These plans are approved and verified before the project continues.
Building a reinforcement cage
Suitable steel bars are cut and bent into the desired shape to satisfy any strength concerns. These bars must be cut using the highest levels of precision to deliver on the required reinforcement and reduce waste.
Form preparation & pre-pour inspection
Steel forms are prepared and then sprayed with a releasing agent to ensure an easy release of the final product. Once the form is prepared, the reinforcement cage is lifted and lowered into the correct position. A certified quality control expert will sign off on this stage before work continues.
The exact concrete mix will depend on the individual project, but it commonly includes cement, coarse aggregates, sand, and other chemical additives. After the concrete is mixed, it is lifted and poured into the form. When the form is filled, it is screeded, and a finish is applied.
Curing & stripping
The concrete is cured in a controlled environment, which allows for accuracy in curing times. After the quality control inspector determines the correct strength is achieved, the form is stripped away, the inner core is collapsed, and lifting attachments are added. The final product is removed, cleaned and sent to have its final inspection.
As precast concrete is exact, a post-pour inspection is carried out. This inspection will ensure that all dimensions are within the desired tolerances and that the concrete is free from defects. After the product passes the inspection, it’ll be transported to the construction site.
Where are precast concrete beams used?
At NVC Precast, we have completed many projects in our years of operation, and we’ve published detailed information on these projects. Other places you may see precast concrete beams include:
- Commercial offices
- Retail and bulky goods structures
- Warehouses and factories
- Cinemas and outdoor theatres
- Multi-unit residential buildings
- Education centres
- Health and aged care
- Clubs, libraries and community centres
- Airports (buildings and parking structures)
Advantages of using precast concrete beams
Precast concrete is a popular part of modern construction for some fundamental reasons. It is strong and increasingly durable, and the installation process is straightforward. Here are some more benefits of using precast concrete beams in any construction project.
- Superior Quality
- Reduces Overall Construction Time
- Can Use Prestressed Concrete
- Enhances Safety at the Construction Site
- Highly Durable
- Promotes Sustainable Construction
- Enhances Project Efficiency
- Increases Project Control
- Aesthetically Pleasing
Disadvantages of using precast concrete beams
Precast concrete has many advantages, but it also has several disadvantages. The main disadvantages of using this method to construct concrete beams are listed here.
- Must Be Transported to the Construction Site
- Susceptible to Damage During Transportation
- Requires Special Equipment
- Improper Installation can Compromise the Structural Integrity
A final word on precast concrete beams
Precast concrete beams offer many advantages to all sorts of construction projects. The beams are strong and built to conform to the specifications set out by engineers, and these beams go through multiple quality control checks before installation occurs.
Provided transportation is completed with caution, and the beams will arrive at the project site ready to install. At NVC Precast, we have a highly experienced team that can construct all types of precast concrete beams and many other precast construction materials. Contact us today for a discussion on what we can do for your existing or future project.