In the UAE, building goes at a speed and columns must go along. From a residential tower in Dubai to an industrial warehouse occupying a vast landfill in Abu Dhabi, precast concrete columns have made a remarkable mark in the region’s skyline in a stealthy fashion. This publication explains what these columns are, where they can be found on live projects, and how the use of columns has become a thing of the past for many contractors.
What is a “Precast” Column?
Precast concrete columns are made in a controlled environment with careful supervision, and are delivered to the construction site and assembled as a single piece. A second approach, an “on-site” cast involves formwork, setting reinforcement, pouring, curing, and stripping and is subject to weather factors and is susceptible to variability from one pour to the next.
With precast, most of that guesswork is eliminated. Accelerated steam curing is used for the production of the columns, where they can be used after about 24 hours, while in-situ concrete has a minimum curing period of seven days. The difference can give a tight schedule project that a project can be pushed back by weeks, especially in the UAE, where nearly every project has a tight schedule.
Essential Shapes and Their Significance
Precast columns aren’t one-size-fits-all. The most common form available in the UAE market is rectangular or square columns, which are mostly found in multi-storey constructions and are in the range of 300×300 mm to 600×600 mm. These are the work horse of the industry – they’re easy to make, easy to attach to beams and work well in the majority of structural frame design.
Uniform strength in all directions is more important than simplicity, and is represented by circular columns. A continuous spiral reinforcement method produces a more ductile piece of a circular column, allowing it to bend and absorb loads more gracefully before it can break, which is very desirable in applications that require resilience under stress, such as seismic resistance or high loads. The decision of rectangular or circular is not necessarily a matter of personal taste, but rather the load pattern and architectural vision.
The applications of Precast Concrete Column Uses in Construction UAE
Precast columns are still some of the most common precast structures used in the UAE, particularly for multi-storey car parks. Precast is the obvious choice for parking structures where repeated column design can be repeated dozens of times without frame redesign and overhangs are required for many clear spans.
Precast is also heavily used in high-rise residential and office buildings. Earning precast usage in high-rise structures is often a matter of speed and quality, and UAE contractors have been using precast columns in residential towers, commercial office buildings, schools, and industrial buildings for decades, not only as a theoretical choice, but as a standard part of active job sites.
The benefit for office and institutional buildings is a little different. Precast skeletal frame systems allow for the simpler realization of open floor plans that are required by today’s office design, instead of having to deal with the myriad of load bearing walls that were typical of older construction.
Last but not least are warehouses and industrial sites. Precast columns are used in combination with precast beams, providing the support for fast-track construction with the focus on getting a building up and running quickly, without sacrificing load bearing capacity, whether it’s housing logistics operations, or manufacturing equipment.
Precast columns extend even into boundary and compound wall systems where precast columns are cast into concrete footings and precast panels are cast to fit into the groves between the precast columns to create a wall. This modular approach is also suitable for non-rectangular plots, which is frequently the case on sites in the UAE where the parcels of land rarely have a neat rectangular form.
Precast Concrete: the reason contractors are still using it
The efficiency argument is a no-brainer. Made to exacting standards, precast columns save the time and effort of on-site construction, and can help boost overall project efficiency, as the heavy lifting is done, quite literally, in the factory, before the project begins on site.
There’s also a quality control part you just might not think of. The rigid control of mix design, curing and quality control is much more difficult to ensure in summer when the concrete is being poured outdoors at 45 degrees. Precast concrete products, including columns, are produced in a controlled factory setting to provide high quality, strength and durability and are quick to install and cost effective on infrastructure or building projects.
The conditions of the site also improve. As fewer wet trades are performed on-site, there is less mess, fewer curing schedule delays and fewer man hours needed than in conventional construction that relies on formwork. That’s more than just a convenience for contractors who are dealing with multiple subcontractors on one job site.
Here are some things to consider before approving a manufacturer
A little background is all that is required to make sure that not all precast suppliers are the same. Ensure that the manufacturer understand that they are not designing a column to a generic template as the load-bearing calculations are very different for a car park column and a car park column supporting multiple floors above.
Inquire about how things are cured and tested for quality. If the manufacturer has taken care in accelerating the curing process and has standardized the testing of the batch, he will generally be able to produce a more consistent product than one that has cut corners to meet a delivery deadline. You may also want to find out if the manufacturer has experience with the type of building you are interested in, as they may not be as experienced with high-rise or industrial-scale projects.
Last but not least, don’t bypass the approval process. When it comes to Dubai, projects must be approved based on Dubai Municipality standards and comparable regulatory approvals are needed in other emirates. A lower-cost column that never passes municipal approval ends up costing much more in delays than does a slightly more expensive column that begins from the ground up as compliant.
A Quick Word on Column Types by Project Scale
For small to mid-rise residential projects, the typical square or rectangular columns will perform as desired and will typically be in common sizes as the load remains relatively predictable. In larger commercial towers and parking structures, a variety of column types may be required—some may be circular for particular load zones, and the rest may be rectangular. Precast is particularly strong in the ability to produce an end product in a repeatable manner, a quality that is often more important than variety in industrial and warehouse projects.
Final Thoughts on Precast Concrete Column Uses in Construction UAE
Precast concrete columns are no longer a “boutique product” in the UAE. That’s why they are now being used by everyone who is building fast, building tall, or building at scale, just because the factory is eliminating the unpredictability of pouring concrete out-of-doors where the climate is not always friendly. From the residential towers to schools, warehouses to multi-level car parks, precast columns are a level of speed and consistency that on-site pouring just cannot match. The only remaining question for developers and contractors is which manufacturer to turn to and what type of column to choose from the options available.
