There are some things in life that seem easy until you are standing in front of a set of structural drawings trying to match the engineer’s specification with what a manufacturer can actually build – column sizing is one of those items. Precast concrete columns are manufactured in the UAE in a specific range of standard sizes and have the flexibility to meet almost any requirement in a structure. Knowing those sizes and why they are affecting them eliminates time, cost and unnecessary on-site coordination issues.
This guide details the typical dimensions of precast concrete columns in the UAE (cross-sections, heights, shapes, tolerances and what makes the choice of size appropriate for a particular use).
Why Size is More Important Than You Might Think
The choice of column size is not just an aesthetic one. It directly affects load capacity, slenderness behaviour, fire resistance rating and ability to achieve appropriate reinforcement cover. If it’s too small for the loads above, you’ll be sent back to the drawing board by your structural engineer. Choose one that is unnecessarily large, and you end up with a loss of floor area, additional dead load, and additional material costs for no structural advantage.
The UAE construction industry is a fast-paced business and making the correct size decision from the outset of a project, before moulds are prepared, and production has started, is essential to keep projects on programme. One other reason for the precast column size discussion being in the design phase rather than on site is that it is made in a factory to order.
Typical Cross Section Dimensions of Precast Concrete Columns
The initial point in any conversation of column size is its cross-section. The typical cross-sectional area range of precast concrete column is as follows throughout international precast practice and in the UAE.
The cross-sectional shape of precast columns is generally square or rectangular, ranging from 300×300 mm up to 600×600 mm for multi-storey building applications. There are also some specialist applications that use circular and L-shaped columns.
The internationally recognised range is wider for a wider industry perspective. Precast concrete columns can have a minimum section of 300×300 mm and the maximum size can be up to 1,200×1,200 mm.
In the UAE project delivery, the most common sizes that are indicated are grouped in the middle of that range. In low rise residential and villa projects 300mm x 300mm and 350mm x 350mm square sections are used in most applications. In medium rise commercial and mixed use buildings, engineers typically work on the 400×400 mm to 500×500 mm level. In high-rise frames and industrial structures with high loadings, 500×500 mm, 600×600 mm and larger are standard sizes.
When the width and depth are not equal, as in the case of unequal load distributions and/or architectural needs, rectangular sections are found in structures. Precast concrete columns are usually square or rectangular, but can be other polygonal shapes or be circular if they are manufactured in a circular mould. The beams supporting the slabs will be supported by the columns, and the loads on the entire area of influence of a column will pass through the beam and into the column. The cross sectional areas are in the range of 40×40 cm to 140×80 cm. The Business Year
The last one is 1400×800 mm which is a very large column, in heavy industrial or infrastructure settings. For practical reasons of transport, crane capacity and manageability of connection details most building projects in the UAE work within the 300 mm to 700 mm range.
Precast Concrete Columns Are Available in a Range of Standard Heights in UAE
The other important dimension is height, and here precast columns in the UAE are especially versatile.
The precast columns in UAE can reach a vertical distance of up to 5 levels (18 metres) in single lift only.
That happens to be one precast unit spanning 5 floors without splicing. That equates to one column unit from ground to Level 5 on a project with 3.6 metre floor-to-floor heights and in one go from a flatbed into position with one crane. The savings in time compared to five separate cast-in-place pours with all of the formwork and curing is considerable.
If the required column height is greater than 18 metres, columns can be manufactured at heights of 20 metres to 24 metres, either as a single uncut column or composite units, each 24 metres in height.
In addition to the column-to-column splicing connections, the structural system is extended up beyond 24 metres, using column-to-column splicing connections. The type of splice depends on the structural engineer’s preference and loading at the splice and is typically made with grouted sleeve connections, threaded rod connectors or cast-in base plate systems.
The single storey and double storey column heights are most common for low-rise applications. The standard single-storey industrial/warehouse column in the UAE is 6-9 metres tall. The standard size of residential buildings is 3 to 5 storeys, and for such buildings, the height of the columns is 10 to 15 metres in a single element and spans the entire structural run.
Circular and Non Rectangular Column Sizes
Not all precast columns are rectangular in UAE. The circular column is commonly found in car parks, commercial building entries, podium structures and wherever aesthetics and traffic flow are equally important.
Circular precast concrete column elements with diameter range of 250 to 800 mm are manufactured and elements with other cross sections (polygonal, oval, etc.) are manufactured on special project orders. Production of concrete grades C30/37 to C55/67 is used.
Circular precast columns are typically found in the UAE market mainly in the size range of 300mm to 600mm diameter which is used in the construction of structures. Higher diameters are used for bridge pier and infrastructure use. Gulf Precast produces columns of various shapes and sizes such as rectangular, circular and even irregular shapes to fit all architectural and structural requirements.
L-shaped and T-shaped columns are used for beam bearing, and are seen in more elaborate structures, with corbels or ledges. They are not taken from a standard catalogue but are specifically designed and sized to meet the structural loads at the particular column location.
Concrete Strength Relates to the Size of the Column
Here’s a useful sizing tip that not only saves money for many projects in UAE but also saves cross-sections: The higher the grade of the concrete the lower the cross-section needed to carry the same load. It’s not some abstract concept; it’s a design optimisation tool that is used every day by UAE structural engineers and precast manufacturers.
In most cases of building columns, the concrete compressive strength is around 4000-5000 psi or about 28-34 MPa. In columns where heavy loads are being carried in high-rise buildings, strengths of 6,000–10,000 psi (around 41–69 MPa) are ordered. The higher strength concrete is more expensive per m3, but results in smaller column cross-sections, recovering floor area. Dubai Municipality
In the UAE precast market, manufacturers are regularly making columns in C40, C45, C50 and C55 grades. Especially, columns in multi-storey buildings, the smaller column footprint (even 50 mm on each side) means that meaningful floor space is released (hundreds of repetitions over a building’s footprint).
The Manufacturing Tolerances of Precast Column Sizes Are Indicated
The nominal size of a precast column is just half the story. Tolerances—the amount of variation from the desired dimensions—are important for structural connections, architectural finishes and interaction with neighbouring precast members.
Generally, the allowable tolerances for precast columns are: cross section dimensions ± 5 mm, length ± 10 mm, straightness of the column L/500 (L is the length of the column) and the twist of the column is 1° per 3 metres of height. Tolerances become more stringent on columns when exposed architectural finishes are required, or when there are mechanical connections that call for tight alignments.
The PCI (Precast/Prestressed Concrete Institute) sets widely-followed tolerance standards for manufactured precast elements. Dimensional tolerances for precast concrete elements range from 0 – 5 feet with a tolerance of + or – 1/4”, and for 5′ to 10′ spans, a tolerance of + or – 3/8”.
The precast manufacturers in the UAE who are certified by Dubai Municipality (DM) for conformity are working under the Dubai Municipality’s precast conformity certification programme which is internationally benchmarked. Any column you receive on site in Dubai or Abu Dhabi from a manufacturer certified through DM has been made and tested to known tolerances — NOT estimated.
Selecting the Correct Size for Your UAE Project
The right column size for any UAE project is determined by a well-defined set of inputs which the engineer of structure controls. Nevertheless, there are some general size rules which hold true for all project types.
In villa and low-rise residential building (usually 1-4 storeys), 300×300 mm or 350×350 mm square columns of concrete C35-C40 meet most structural needs. These are the most common sizes of the Villa precast works Dubai, Abu Dhabi and Sharjah.
The typical specification for C40 to C50 concrete sections for medium-rise commercial and mixed-use buildings (5 to 15 storeys) is 400×400 mm to 500×500 mm. C50 or C55 concrete is commonly used at the lower floors where the axial loads are greater and it can be reduced at the upper floors where the axial loads are reduced to C40.
In UAE, the most common precast application is in car parking structures, where the size of the columns depend on the size of the structural bay. The most frequently used cross section for precast columns in parking structures is 600 mm × 600 mm (24 × 24 inches). If the column supports considerable loads on several floors or has a wide bay, it can have a rectangular shape, e.g., 600×900 mm. Where extra thick sections are required for specific projects they are available.
Large span industrial warehouses and logistics centres like JAFZA, DIP and Abu Dhabi industrial zones generally require columns from 9m to 14m in height with sections between 400×400mm and 600×600mm depending on the applications and roof loads, as defined by the structural engineer.
The Following Tips Are Helpful When Confirming With Your Precast Supplier
A few points come into mind when you call a UAE precast column manufacturer, that would help you get the conversation to a quick and accurate quotation and production.
Verify the design axial load for each column location, required floor to floor height, structural grid spacing (which will result in beam span) and type of frame system (braced or unbraced). Also define if corbels or cast-in plates for beam bearing are to be included as part of the column unit, these will increase the dimensions and weight and will have an impact on planning for transport.
A precast column is structurally unstable right after casting — before the grouting is cured. Prior to releasing the crane hook, temporary steel props or guy wiring should be placed. When performing erection stability calculations, it is important to verify that the element will not overturn under self-weight plus wind load in the temporary condition.
This is a temporary stability requirement as part of the erection engineering and a reputable precast manufacturer of the UAE will provide this with their shop drawings.
Final Thoughts on Precast Concrete Columns
Precast concrete columns are available in a variety of sizes, typically ranging from 300×300 mm for low-rise use up to 1,200×1,200 mm for heavy industrial applications, the single column height can reach up to 18 metres in a single run and up to 24 metres for special requirements in the UAE. Concrete grades range from C35 to C55, the higher grades being used for leaner cross-sections. Concrete grades range from C35 to C55 with higher grades used for leaner cross-sections.
All of these sizes are not random! All dimensions are a mix of structural engineering, feasibility in manufacturing, transport logistics, and quality demands of the UAE’s regulatory system.
When you select a manufacturer that is DM certified, involve their engineering team early in the project design phase and it’s one of the easy decisions, not one of the stressful ones, that you’ll make when you are sizing the column.