Precast Column

What is a precast column?

A precast column is a vertical reinforced concrete member cast in a controlled plant environment, delivered to site ready to install and set into its foundation. In precast buildings, columns collect the loads coming from roof girders, beams and gutter beams and carry them down to the foundations.

Its role in an industrial building

In single-story factories and warehouses, columns are the main members resisting both vertical loads and lateral actions such as wind and earthquakes. They are typically fixed rigidly into the foundation, while the beams resting on them are usually connected with pinned joints. As a result, the column section, its reinforcement and its foundation connection directly govern how the building performs in an earthquake.

Sections and details

Precast columns are most often produced with square or rectangular sections. Depending on the project, a column may include:

• Corbels supporting beams, roof girders or crane beams
• Holes and sleeves for connection dowels, plus cast-in connection plates
• Fixings for facade panels and cladding substructures
• Internal voids for rainwater downpipes

Section size, column height, corbel levels and reinforcement layout are set for each building by the structural design. Rather than a fixed catalog of sizes, the loads and spans of your project drive the design.

Production

Columns are cast in steel molds adjusted to the project dimensions, once the reinforcement cage and cast-in parts are in place. A column is not demolded or shipped until the concrete has reached the required strength. Before casting, the position of reinforcement, cover and cast-in parts is checked, and concrete strength is tracked with test specimens. Plant production makes concrete quality, cover and dimensional tolerances far easier to control than on a construction site.

Erection

On site, columns are lifted by mobile crane into prepared socket (pocket) foundations. Once plumb and at the correct level, each column is temporarily braced and the socket gap is filled with high-strength grout or concrete. When the infill has gained sufficient strength, beams and roof elements are placed on top.

How it differs from a cast-in-place column

With a cast-in-place column, formwork, reinforcement and concreting all happen on site; every column means waiting for the forms to be set, poured and struck, and progress depends on the weather. A precast column is produced in the plant while foundation work continues on site, and is set in place quickly once it arrives. Working with the same molds and the same production routine also keeps dimensional and quality differences between columns to a minimum.

What we need for a quote

The site location, approximate building dimensions, column grid, building height and any overhead crane requirements are enough to get started. Final dimensions are confirmed by the structural design.