In industrial environments, especially chemical manufacturing units, structural failures can lead to far-reaching consequences—endangering both life and operations. This case study outlines an urgent intervention undertaken to rehabilitate a structurally distressed RCC column located on the 4th floor of an 8-storey chemical processing unit, where uninterrupted production was as important as ensuring structural safety.
Observation
During routine structural maintenance, a vertical RCC column on the 4th floor displayed sudden buckling of reinforcement steel—detected within just 10 minutes of removing the damaged cover concrete.
Key facts:
- Location of the column: 4th floor, corner of the 8-storey unit
- Function of the building: Processing and storage of corrosive chemicals, which is highly aggressive to concrete
- Live and dynamic load on the 8th floor included:
- A 50 MT capacity water tank, filled at the time
- Multiple running high-RPM machines and dynamic equipment
Due to its corner location, the column carried significant axial and moment loads, making its sudden distress particularly alarming.
Rising Anxiety
The buckling event immediately shifted the perceived safety of the entire unit to an ‘unsafe’ zone. There was no time for root cause analysis—the focus had to shift to emergency restoration.
Immediate precautions taken:
- Shutdown of high-RPM equipment to minimize dynamic loads
- Draining of the water tank on the top floor to reduce vertical stress
- Restricted personnel access to the affected zone
The intent was clear: preserve safety while devising a plan that could accommodate the operational urgency of the plant.
Operational Constraints
Upon initial assessment, engineers estimated:
- The time required for full rehabilitation of the 4th-floor column: approximately 50 hours
- This duration was not acceptable to the management, given the operational importance of the unit and pressure from the marketing team
A rapid, feasible, and structurally sound solution had to be devised—one that could allow operations to resume safely before the complete repair was executed.
Assessment and Data Summary
An internal brainstorming session led to a segmented structural analysis of the column:
- Total height of column (floor-to-floor): 6.0 meters
- Height already rehabilitated: 2.0 meters
- Height where reinforcement was exposed and buckled: 1.5 meters
- Remaining unrepaired height: 2.5 meters
- Estimated time for this segment’s rehabilitation: 50 hours
The segment that hadn’t yet been opened was the most dangerous—it posed an unknown internal condition that couldn’t be verified due to intact concrete cover. This “blind zone” had the potential to fail unexpectedly, making confinement of that section an urgent priority.
Key Engineering Insight
RCC columns rely on the integrity of confinement—the synergy of reinforcement and surrounding concrete. When confinement is lost or disturbed:
- The column’s axial load-bearing capacity is compromised
- Structural instability becomes highly probable
- Progressive failure can trigger collapse across connected floors
Thus, even though only one section of the column remained untreated, resuming operations without containing this zone was deemed highly risky.
Innovative Temporary Stabilization
An innovative metal confinement system was conceptualized and executed. The solution used mild steel (MS) box jackets fabricated on-site and installed swiftly.
Design details:
- Material: 6 mm thick MS plates
- Size: 300 mm high boxes
- Fabrication: Split into two halves for easy placement
- Jointing method: Flanged ends on both halves, bolt-fixed with tight torque to ensure firm confinement
- Installation pattern: Boxes installed at 300 mm intervals, covering the unrepaired zone
Fabrication + fixing timeline: Completed within 3 hours of conceptualization.
This system provided a temporary confinement shell, protecting the core structure from unexpected bursting or further distress, without interfering with future rehabilitation.
Reinstating Operations
With the MS confinement in place:
- The water tank was refilled
- Operations resumed, safely and successfully—well before the 50-hour mark
The emergency system performed as intended, preventing further deformation and preserving the column’s ability to transfer vertical loads temporarily.
Final Rehabilitation Approach
With operational pressure reduced, full rehabilitation was carried out in a controlled, segmented process:
- MS boxes were removed one by one
- The column was rehabilitated in 600 mm vertical segments
- Despite initial fears, no concrete bursting occurred during removal, suggesting that the confinement strategy effectively stabilized the internal stress
Conclusion
This case exemplifies the delicate yet essential balance between maintaining production continuity and upholding structural safety in industrial environments. Faced with a potentially catastrophic situation, the team responded with sound engineering judgment and swift on-site adaptability. The decision to confine the damaged RCC column using fabricated modular steel boxes provided a practical and immediate solution, allowing plant operations to resume without waiting for full rehabilitation. The success of this interim measure was rooted in fast execution, meticulous planning, and a deep understanding of structural behavior under stress.
The outcome reinforces several key lessons: temporary confinement methods can be highly effective during emergencies; modular fabrication accelerates implementation; and, most importantly, operations can be safely resumed ahead of schedule when the risks are clearly identified and mitigated. This case reaffirms a fundamental principle—production must go on, but never at the cost of safety.
About the author;
Er. Chirag K. Baxi is the Director of Prudent Forensic Consultancy Private Limited and General Manager of K K Retroflex Solutions. He specializes in Corrosion Control Measures for concrete and steel surfaces, Damage assessment with the FORENSIC ENGINEERING approach and Structural rehabilitation of concrete and steel structures in the Industrial environment. He holds a degree in BE (Civil Engineering) and has completed MBA (Construction Management).
The author has invented CONCARE B 14 (which has been granted a patent) that makes concrete structures sustainable even with salty, saline, untreated or even seawater without deterioration in any of the end properties of constructed elements. He has written (two) drafts of IS Codes on the topic of “Carbon brick lining” and “PolyPropylene Glass lining” which are under the final stage of approval at BIS.
About 40 Technical papers on National and International platforms are authored, published and presented by the author. He has been recognized by several Institutes for his significant contribution to the Civil Engineering Industry.
