A brick column is a vertical structural member made of bricks and mortar. It is used to support loads from beams, slabs, or other structural members.

This type of column is mostly found in ancient historical structures. They are well known for their strength, durability, and classical architecture.

Brick columns provide resistance to compressive stresses from the weight above. They are often used in buildings to support floors or roofs.

Types of Brick Columns

There are several types of brick columns:

• Solid brick columns: Made entirely of bricks with mortar in between each layer. They provide high load-bearing capacity but take up more space.
• Hollow brick columns: Have a cavity in the center to reduce weight and material usage. The cavity may be left empty or filled with concrete. Hollow columns are more vulnerable to cracking.
• Reinforced brick columns: Contain steel reinforcement bars (rebar) running vertically through the column. The rebar improves the column’s tensile strength and resistance to cracking or buckling.
• depending on the shapes they may be different types like circular, rectangular, square, etc.

Applications of Brick Columns

They have served important structural purposes throughout history.

Today, they continue finding use in new construction and renovation projects for their strength, durability, and design flexibility. Common applications include:

Supporting Floors and Roofs
One of the most frequent uses is to support concrete beams, wood joists, or steel girders that frame floors and roofs.

By transferring loads downwards into the foundation, these provide critical support to keep the spanning members in place. They are installed underneath key points along the framing system.

Carrying Masonry Walls
In multistory buildings, large columns may directly carry the weight of heavy masonry exterior walls.

This allows the walls to rise to greater heights without buckling or requiring extremely thick wall sections. They activate high compressive strength to support the wall’s self-weight and any lateral wind loads.

Decoration and Aesthetics
Architects often choose them for their attractive appearance that lends a stately, sophisticated look.

Brick offers a traditional masonry aesthetic, providing textural and color contrast with surrounding walls. Brick columns can be built in various patterns for unique decorative effects.

Sustaining Porch Roofs
They feature prominently as vertical supports for open-air porches on houses.

They raise porch roofs to the desired height while framing the outdoor living space. Resilient to weathering, brick blends with natural landscape surroundings.

Earthquake and Wind Resistance
Properly reinforced brick columns provide good seismic resistance and lateral load capacity in areas prone to earthquakes or hurricanes.

Horizontal steel ties connect the masonry wythes together against racking motions while the bricks sustain heavy vertical loads.

Design Considerations

Key design specifications for brick columns include:

• Load capacity: Determined based on the expected vertical load from above and allowable soil bearing capacity below.
• Column dimensions: Calculated to provide adequate load capacity. Column height depends on floor heights.
• Reinforcement: Steel rebar improves tensile and shear strength. Horizontal ties resist cracking.
• Mortar type: Higher strength mortar provides improved compression and weather resistance.

Brick masonry column design—step by step

The design of a brick column starts from load estimation and ends with checking permissible stress in brick masonry. Use a simple, repeatable sequence for safe design.

1. Estimate design load
   Calculate the factored axial load from slabs, beams, and walls supported by the brick column. Include self-weight and a suitable load factor as per your building code.
2. Select trial size
   Choose a practical brick column size, such as 230 mm × 230 mm or 230 mm × 345 mm, based on wall thickness and layout. Check that the slenderness ratio (effective height ÷ effective thickness) is within code limits for brick masonry column design.
3. Decide on an unreinforced or reinforced brick column
   For small loads and low heights, an unreinforced brick column may be enough. For higher loads, seismic zones, or higher slenderness, use a reinforced brick column with vertical bars and ties.
4. Choose brick-and-mortar grade
   Select brick compressive strength and mortar grade as per IS 1077 and IS 1905 or equivalent. Higher mortar grade improves permissible stress in brick masonry.
5. Compute permissible and actual stress
   Get base permissible compressive stress from IS 1905 tables for the chosen brick and mortar. Apply reduction factors for thickness, slenderness, eccentricity, and shape as required by the code.
6. Check stress and revise size if needed
   Compute axial stress using σ = P ÷ A, where P is factored axial load and A is the net cross-sectional area. Ensure that actual stress is less than or equal to permissible stress in brick masonry for a safe design.

Worked example – 3 m high brick column

This simple example shows basic checks for a short brick column under axial load.

• Given data: brick column 230 mm × 230 mm in plan, clear height 3.0 m, service axial load 150 kN.
• Cross-sectional area: A = 230 × 230 = 52,900 mm².
• Axial stress: σ_act = P ÷ A ≈ (150 × 10³) ÷ 52,900 ≈ 2.84 N/mm².

Assume bricks of compressive strength 10 N/mm² with M1 mortar. From IS 1905 tables, the basic permissible compressive stress for similar masonry is of the order of 0.8 – 0.96 N/mm² before applying reduction factors.

In practice, the designer should:

• Compute effective height and effective thickness of the brick column.
• Apply slenderness and area reduction factors from IS 1905 to modify the base permissible stress.
• Increase column size or provide reinforcement until σ_act is less than or equal to permissible stress in brick masonry.

This worked example is only illustrative. Final design of brick masonry column design should always follow the full code provisions and engineering judgment.

Brick Column Construction

The step-by-step process for installing brick columns is

1. Excavate for column foundations and construct concrete pad footing
2. Build formwork defining shape and dimensions of the column.
3. Insert vertical steel rebar, ensuring adequate anchorage and splicing
4. Apply mortar and begin laying bricks, using leveling tools to verify plumb alignment
5. Insert lateral ties/bands during construction to connect wythes and resist cracking
6. Fill column cavity with grout/concrete as needed during construction
7. Remove formwork after completion, and backfill soil around the column.

Failure modes of brick columns

Brick columns can fail in different ways if they are not designed and detailed properly.

• Crushing failure: Short, stocky columns with low slenderness fail by compressive crushing of bricks and mortar near the loaded regions.
• Buckling failure: Slender brick columns may buckle sideways before the masonry crushes. The risk increases as slenderness ratio increases.
• Eccentric loading and cracking: When loads are not applied at the centre of the column, cracks form on the tension side. These cracks reduce stiffness and can lead to early failure.
• Bond failure: Poor bond between bricks and mortar, or between masonry and reinforcing steel, can cause local splitting and bond failure.

Good brick column construction details help control these failure modes. Provide proper footing, full mortar joints, correct bar placement, and adequate curing to improve performance.

Design limitations – quick reference

• Slenderness ratio: For unreinforced brick columns, keep slenderness ratio (effective height ÷ effective thickness) within the limits given in the masonry code, often around 15 for axially loaded columns.
• Reinforced brick columns: With vertical bars and ties, some guidelines allow slenderness ratios up to about 20 for axially loaded reinforced brick columns, subject to detailed checks.
• Practical height: For typical low-rise buildings, brick columns are most reliable up to one or two storeys. Taller columns should be designed and checked by a structural engineer.
• Eccentricity control: Avoid large eccentricity at beam–column junctions. Use bearing plates or concrete caps to spread loads and keep them closer to the column centre.

Design equations for brick columns

Brick columns are designed by comparing actual stress with permissible stress in brick masonry.

1. Actual axial stress

σ_act = P ÷ A

where P = factored axial load on the column, and A = net cross-sectional area of the column.

2. Permissible compressive stress

σ_perm = f_c × K_m × K_s × K_l × K_t

where f_c is basic permissible stress from IS 1905 tables, and K_m, K_s, K_l, K_t are factors for mortar grade, shape, slenderness, and thickness.

3. Design check

For safe brick masonry column design, ensure that:

σ_act ≤ σ_perm

Teaching examples for 10 N/mm² bricks with M1 mortar show permissible compressive stresses around 0.8 – 0.96 N/mm² before slenderness reduction, but the designer must always use the exact values from the latest code.

Brick column vs RCC column vs steel column

Choice of column type depends on load level, speed of construction, budget, and durability requirements. The table below compares brick columns, RCC columns, and steel columns.

For small residential work, a brick column can be cheaper, but for multi-storey projects an RCC column or steel column is usually more efficient. This is why many designers prefer RCC when deciding between a brick column vs RCC column for new framed buildings.

FAQs on brick columns

Conclusion

Brick columns provide efficient load-bearing structural members for buildings. When properly designed and constructed, they safely transfer vertical loads through compressive stresses within the masonry.

The type, dimensions, and reinforcement levels for brick columns depend on intended loading conditions and architectural requirements.

Following best practices for installation ensures maintaining long-term strength and stability.