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Last edited 08 Sep 2026

Application of RCC Column Jacketing Services

1 Introduction
2 Related articles on Designing Buildings

[edit] Introduction

Reinforced concrete column jacketing is a structural strengthening technique used to improve the performance of existing reinforced concrete columns. It may be undertaken where columns have deteriorated, sustained damage, require increased load capacity or do not provide the level of structural performance required for their intended use.

The term reinforced cement concrete (RCC) is widely used in some regions to describe reinforced concrete (RC). In structural engineering, reinforced concrete is generally the preferred term.

Concrete jacketing involves adding a new reinforced concrete layer around an existing column. The jacket may incorporate additional longitudinal and transverse reinforcement and is designed to act with the existing structural member. Depending on the structural assessment and design, jacketing may increase axial load capacity, flexural and shear resistance, stiffness and ductility.

Column jacketing should only be specified following an appropriate structural investigation. The cause of deterioration or inadequate performance must be identified, and the strengthening system designed as part of an assessment of the wider structure.

[edit] Applications of reinforced concrete column jacketing

Reinforced concrete column jacketing may be used in a range of structural repair, rehabilitation and strengthening projects.

[edit] Strengthening deteriorated or damaged columns

Columns may deteriorate as a result of ageing, environmental exposure, reinforcement corrosion, construction defects, impact damage or other causes. Cracking, spalling, exposed reinforcement and loss of concrete cover can indicate deterioration, although the significance of these defects requires engineering assessment.

Before jacketing is undertaken, the underlying cause of the damage should be identified and addressed where possible. For example, reinforcement corrosion may be associated with carbonation, chloride contamination or persistent moisture ingress. Simply enclosing deteriorated concrete within a new jacket without addressing the cause of deterioration may not provide a durable solution.

Column jacketing may form part of a repair strategy to restore or improve structural capacity, provided that the existing member and the proposed strengthening system have been appropriately assessed and designed.

[edit] Increasing load-bearing capacity

Changes in the use or configuration of a building can increase the loads imposed on existing columns. Examples may include:

The addition of storeys or extensions.
Changes in building use or occupancy.
Installation of heavier equipment or machinery.
Alterations to floor layouts or load paths.
Changes to imposed or environmental loading requirements.

Concrete jacketing can increase the cross-sectional dimensions and reinforcement of a column, potentially increasing its structural capacity. However, the effect on foundations, beams, slabs and the wider structural system must also be considered. Strengthening an individual column may transfer additional forces to other elements that were not designed for them.

[edit] Structural rehabilitation and refurbishment

Column jacketing may be used during the refurbishment or rehabilitation of existing buildings and civil engineering structures where structural assessment identifies deficiencies in columns or other structural members.

Applications may include residential, commercial, industrial, educational and healthcare buildings, as well as bridges and other civil engineering structures. The technique may be considered where strengthening is more practical than demolition and reconstruction, although the suitability of this approach depends on structural, technical and economic factors.

[edit] Seismic strengthening

In areas where earthquake loading is a significant design consideration, column jacketing may be used as part of a wider seismic strengthening strategy. Appropriately designed jacketing can improve the confinement of concrete and reinforcement, enhance ductility and improve the behaviour of structural members under cyclic loading.

Seismic strengthening should consider the performance of the entire structural system rather than individual columns in isolation. The connections between columns, beams, slabs, foundations and lateral load-resisting elements may all affect the performance of the building during an earthquake.

[edit] Industrial and heavily loaded structures

Industrial buildings and infrastructure may be subject to heavy static loads, repeated loading, vibration, chemical exposure or changes in operational requirements. Structural strengthening may therefore be required where an assessment identifies inadequate capacity or deterioration.

Column jacketing may be used in factories, warehouses, power facilities and other industrial structures, subject to consideration of access, construction sequencing, operational disruption and exposure conditions. Where aggressive environmental conditions are present, the repair and strengthening system should include appropriate durability measures.

[edit] Fire-damaged structures

Exposure to fire can affect the properties of concrete and reinforcement, with the extent of damage depending on factors such as temperature, duration of exposure, heating rate and subsequent cooling.

Fire-damaged reinforced concrete columns should be investigated before repair or strengthening is specified. Assessment may include examination of cracking and spalling, material testing, evaluation of reinforcement and determination of residual structural capacity.

Concrete jacketing may be one of several strengthening options where structural assessment confirms its suitability. Other repairs or protective measures may also be required depending on the extent and nature of the fire damage.

[edit] Advantages and limitations

Potential advantages of reinforced concrete column jacketing include:

Increased load-bearing capacity.
Improved flexural and shear resistance.
Enhanced stiffness and reduced deformation.
Improved ductility where appropriately detailed.
The ability to repair and strengthen existing structural members.
Potential extension of structural service life.
Avoidance of complete demolition and replacement in some circumstances.

However, concrete jacketing also has limitations. It increases the dimensions and weight of the strengthened column and may reduce usable floor space or affect architectural layouts. The additional loads imposed on foundations and other structural elements must be assessed.

Construction can also be disruptive, particularly where columns are located within occupied buildings or operational facilities. Temporary works, load transfer and construction sequencing may be required to ensure structural safety during the strengthening process.

Column jacketing is therefore not automatically the most suitable strengthening method. Alternatives such as steel jacketing, fibre-reinforced polymer strengthening, additional structural members or other repair and strengthening techniques may be more appropriate depending on the nature of the structure and the required performance.

[edit] Column jacketing process

The precise procedure for reinforced concrete column jacketing varies according to the structural design, condition of the existing column and materials used. A typical process may include the following stages.

[edit] Structural assessment and design

A structural engineer should assess the existing structure to determine its condition, dimensions, reinforcement, loading and required performance. Investigations may include visual inspection, measurement, material testing and examination of drawings or other available information.

The assessment should establish the cause and extent of any deterioration and determine whether jacketing is an appropriate solution. The jacket and its reinforcement should then be designed in accordance with applicable structural design standards and project requirements.

[edit] Preparation and repair

Unsound or damaged concrete may be removed and the existing surface prepared to achieve the required condition for the proposed strengthening system. Corroded reinforcement should be assessed and treated, supplemented or replaced where necessary.

Preparation requirements depend on the repair specification and the intended interface between the existing column and the new jacket.

[edit] Installation of reinforcement and formwork

Additional reinforcement is installed in accordance with the structural design. This may include longitudinal reinforcement and transverse reinforcement to provide the required confinement and structural performance.

Reinforcement detailing, anchorage and connections to the existing structure are important aspects of the design. Formwork may then be installed where required to contain the new concrete or other cementitious material.

[edit] Placement and curing

The jacket may be formed using conventional concrete, micro concrete or another suitable repair material. The choice of material depends on factors including jacket dimensions, reinforcement congestion, access and placement requirements.

Micro concrete is sometimes used where a highly flowable, low-shrinkage material is required to fill confined spaces around reinforcement. Material selection should be based on compatibility with the existing structure and the structural and durability requirements of the project.

Placement, curing and quality control should be carried out in accordance with the project specification and the requirements for the selected materials.

[edit] Inspection and quality assurance

Completed strengthening work should be inspected to verify that the specified materials, reinforcement, dimensions and construction procedures have been achieved. Records of investigations, design decisions, materials and construction activities may form part of the project's quality assurance documentation.

[edit] Indicators requiring structural investigation

Certain defects or changes in a building may indicate the need for structural investigation. These can include:

Significant or recurring cracks in columns or other structural elements.
Concrete spalling or delamination.
Exposed or corroded reinforcement.
Rust staining associated with reinforcement corrosion.
Unusual deflection or distortion.
Evidence of settlement or movement.
Water ingress affecting structural elements.
Changes in use or loading.
Fire, impact or earthquake damage.

These signs do not necessarily mean that column jacketing is required. Their cause and structural significance should be assessed before selecting a repair or strengthening method.

[edit] Conclusion

Reinforced concrete column jacketing is an established technique for the repair and strengthening of existing structural members. It may be used to address deterioration, increase load capacity, improve ductility or support wider structural rehabilitation and seismic strengthening programmes.

The success of column jacketing depends on a thorough assessment of the existing structure, identification of the causes of deterioration, appropriate structural design, compatible materials and effective construction quality control. The strengthened column must also be considered as part of the wider structural system, including the effects on connected elements and foundations.

Where appropriately designed and installed, concrete jacketing can provide a means of extending the service life and improving the performance of existing reinforced concrete structures without requiring complete demolition and replacement.