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Reinforced Precast Concrete Columns: Overview and Applications

What are reinforced precast concrete columns? What are their different applications? Let’s explore everything you need to know about this structural element.

Modern construction has seen a growing adoption of innovative and efficient solutions to meet the design, construction, and durability needs of structures. Among these solutions, precast concrete structural columns represent a significant turning point in the civil engineering sector. These structural elements, manufactured in factories and transported to the construction site, offer numerous advantages over traditional columns built on-site.

Let’s delve into the definition, production process, applications, and also analyze the connections and assembly of this type of structure in detail.

Finally, you can watch a video showing how you can use a structural calculation software for the design of reinforced precast concrete columns.

Prefabricated structure under construction

Prefabricated structure under construction

Definition of Reinforced Precast Concrete Columns

Precast concrete structural columns are a fundamental structural solution in the modern construction landscape. Essentially, these columns are vertical structures designed to support other building components such as beams, slabs, and roofs. What sets them apart is the prefabrication process, which makes them particularly advantageous in terms of precision, construction times, and strength.

The dimensions of precast columns can vary, depending on the project specifications, and can have varying heights. This flexibility allows designers to adapt the columns to the structural and architectural needs of the building, ensuring optimal space utilization and efficient distribution of loads.

Precast concrete structural columns are a versatile and reliable solution for modern building structures. They combine the intrinsic advantages of reinforced concrete with the benefits of prefabrication, including fast assembly, cost savings, reduced environmental impact, and design versatility. These columns are essential to ensure the stability and safety of constructions, while offering high construction efficiency and excellent long-term durability.

Production Process of Reinforced Precast Concrete Columns

The production process of precast concrete structural columns is an articulated and methodical process that unfolds through different phases, from project ideation to fabrication in the factory and installation on the construction site. These phases are crucial to ensure the quality, precision, and efficiency of precast columns.

Structural Frames in the Factory

The process begins with a careful analysis of the project by the company’s technical office. This fundamental step allows for the subdivision of the structural mesh into manageable pieces, maintaining dimensions that allow easy transportation to the construction site.

The design phase is a crucial moment where the characteristics and specifications of the precast column are defined. The choice of elements and their arrangement within the structure are crucial for the correct static functioning of the building.

The quality office ensures that all current regulatory requirements are met during production, ensuring the compliance of the final product.

Site Preparation and Fabrication

Once the design is complete, the site preparation phase begins. This may include land preparation, installation of necessary equipment and machinery for production and handling of columns, as well as securing the work area.

Another phase is the actual fabrication of the column in the factory. This process involves careful analysis, testing, and verification to obtain a certified product accompanied by complete technical documentation. The reinforced concrete is then poured into specially designed molds that give the desired shape to the column. During this process, it is essential to carefully control the concrete mix and ensure that it is evenly distributed inside the module to guarantee the solidity and durability of the column.

After pouring the concrete, the column is left to cure and mature. This process, known as curing, can take several days depending on environmental conditions and the specific type of concrete used. During this period, it is important to keep the column moist and protected from external weather agents to promote proper cement maturation and ensure maximum structural strength.

These are two distinct and separate steps that can actually develop in parallel. This is one of the major advantages of this type of structure, as it speeds up work and reduces construction times.

Transportation and Installation

Once the column has reached the necessary strength, it is transported to the construction site and installed according to the project specifications. This process requires attention and precision to ensure that the column is correctly positioned and effectively integrated with the rest of the building structure.

Transport and installation of precast concrete structural column

Transport and installation of precast concrete structural columns

Applications and Uses

Precast concrete structural columns can be used for a wide range of applications in construction, offering numerous advantages in terms of efficiency, strength, and design versatility.

Residential Construction

In residential projects, precast concrete columns are used for the construction of condominiums, residential complexes, and single-family homes. Their ability to support heavy loads and withstand adverse weather conditions makes them ideal for residential buildings of various sizes and types.

Commercial Construction

In the commercial sector, precast columns are widely used in the construction of high-quality structures such as offices, shopping malls, hotels, and industrial complexes. The ability to customize the dimensions and characteristics of the columns makes them suitable for meeting the specific needs of each project, ensuring structural strength and long-term durability.

Public Infrastructure

In addition to residential and commercial buildings, precast concrete structural columns are also used in the construction of public infrastructure such as hospitals, schools, railway stations, and airports. Their ability to support heavy loads and withstand dynamic stresses makes them ideal for large-scale and complex infrastructure projects.

Civil Engineering Works

Finally, precast columns are also used in civil engineering works such as bridges, viaducts, and tunnels, allowing for the construction of large and long-lasting structures while ensuring rapid execution of works and overall cost reduction of the project.

Connections and Supports

In the context of precast concrete structural columns, connections and supports play a fundamental role in ensuring structural stability and membrane continuity.

Foundation Connection: Types and Design

The connection of columns to the foundation is done using different types of systems, including prefabricated “shoes.” These “shoes” are made of steel inserts, commonly used for connecting columns to foundations. During the foundation construction phase, anchor bolts are placed in the reinforcement cage, allowing the columns to be anchored with the help of nuts and washers.

Prefabricated “shoes” offer several advantages, including ease of assembly, dimensional precision, and reduced construction times. If necessary, the system can be integrated with the use of additional reinforcements, such as stirrups inserted in the columns, without compromising the advantages offered by prefabrication.

Beam Support on Precast Columns: Solutions and Evolution

The structural node between beams and columns is a critical point in the design of precast columns. There are several solutions to ensure proper support of beams on columns, including the use of reinforced concrete corbels.

One of the most common solutions involves the tapering of the column’s reinforcements at the node, allowing direct support of the beams on the shaft. This approach, although incurring additional costs for reinforcement and assembly, ensures greater precision and structural stability.

Other solutions involve the use of temporary or permanent corbels, made of reinforced concrete or steel. These corbels support the loads of beams during the assembly phase and ensure structural continuity of the node. However, these solutions may entail additional costs and require greater precision in design and production.

Beam support on precast concrete structural column

Beam support on precast concrete structural column

How to Assemble Precast Concrete Structural Columns

The assembly of reinforced precast concrete columns takes place through different phases, depending on the morphology and connections used.

Dry Assembly Phases with “Shoe” Morphology

Preparation of the Installation Site

During this phase, the positioning template of the anchor bolts is removed, leaving the lower nuts and washers for the installation of the shoes. This preparation is crucial to ensure correct alignment of the column.

Handling of the Element

  • Hooking – the pin and safety clips are inserted to ensure stability during lifting.
  • Lifting and Placement – the column is lifted and placed on the lower layer of nuts and washers of the anchor bolts. During descent, it is guided by operators to ensure precise positioning.
  • Alignment and Elevation – ensures that the column is perfectly vertical and at the desired elevation by adjusting the lower nuts.
  • Locking and Fastening – all adjustments are locked, and the upper nuts are permanently fastened.

Preparation of the Ground Connection:

The connection area is shuttered using wooden strips and the edges are sealed with polyurethane foam to prevent mortar leakage.

Dry Assembly Phases without “Shoe” Morphology

Preparation of the Installation Site

In this phase, a steel plate is placed inside the previously prepared callouts, positioned centrally with respect to the contact section. This is essential to keep the column raised from the foundation.

Handling of the Element

  • Hooking – the pin and safety clips are inserted to ensure stability.
  • Lifting and Placement – the column is lifted and placed on the steel plates, aligning it precisely with the callouts. Precision in executing the callouts is essential to ensure the correct positioning of the column.
  • Alignment – using a level-equipped stadia, the verticality of the column is ensured.
  • Fastening of Push-Pull Props – props are securely fastened to the column and foundation to maintain the position.

Preparation of the Ground Connection

The connection area is shuttered, and the edges are sealed to prevent mortar leakage.

In both cases, the assembly is completed by definitively tightening the anchor bolts and, if necessary, by pouring grout between the bottom of the column and the foundation. The grouts used must guarantee strength, fluidity, and adhesion without shrinkage phenomena.

Structural Calculation Software: the Video

Here is a video showing how you can use a structural calculation software to design structures with reinforced precast concrete columns.