When structures speak: How vibration monitoring revealed a hidden weakness

Case Study

Dr. Sauvik Banerjee, Co-founder & Director, Nirixense Technologies (August 2025)

In the world of modern infrastructure, persistent vibrations are more than a nuisance. They’re often a sign of deeper structural issues. This short article emphasizes how vibration monitoring in an institutional building uncovered a stiffness deficiency in a circular foyer slab system, and how a targeted intervention helped address the root cause before it escalated.

The problem: Vibrations in a semi-circular common area

Occupants of a multi-story institutional complex reported noticeable vibrations in a circular foyer area connected to staircases across three floors. The design featured long-span, semi-circular slabs supported by circular exterior columns but lacked critical end-span beam connections. Cracks in some beams raised concerns about structural integrity and shear capacity.

The investigation

A focused vibration monitoring effort was conducted, with following objectives:

Record vibration characteristics in the affected zones.
Compare slab frequencies with human-induced vibration ranges.
Diagnose possible causes like low stiffness or support deficiencies supported by full-scale modelling.

Key findings

Natural frequency concern: The natural frequency of the slab was approximately 5Hz. This is close to frequencies caused by foot traffic, creating noticeable but non-resonant vibrations.
Weakness in stiffness: Persistent vibrations were observed, implying that factors such as stiffness of the slab may be influencing the sustained oscillations.
Support weakness: Absence of beam connections and cracks in existing beams revealed deficiencies in shear and inadequate damping, amplifying vibrations.

Vibration testing

Structural deficiencies

Remediation

The root cause was identified as inadequate stiffness. A non-intrusive solution involving carbon-fiber reinforcement plates was recommended to enhance stiffness and reduce vibrations without major modifications, drastic enhancement of dead loads or reconstruction.

Why It matters for Facility Managers, Architects & Builders

Proactive diagnostics prevent small issues from becoming structural problems.
Occupant comfort influences trust and perception in public spaces.
Smart retrofitting like carbon-fiber solutions offer cost-effective, minimal-disruption fixes.

Structural health isn’t always visible. This case underscores the power of vibration monitoring as a preventative tool, not just for diagnosis, but for ensuring safety, comfort, and longevity in modern structures.

About the Author: Dr. Sauvik Banerjee is Co-founder & Director at Nirixense Technologies, and Professor at Department of Civil Engineering, IIT Bombay. His experience includes structural health monitoring, using wave propagation and vibration-based approaches, quantitative nondestructive evaluation of structures, nondestructive testing, modelling of advanced composite structures, structural retrofitting and impact response of structures. He obtained Ph.D. degree from UCLA (Mechanical Engineering, 2003), M.Tech. from IIT Bombay (Civil Engineering, 2001).

Note: This article presents the author’s personal views and insights drawn from publicly shareable aspects of research and consultancy projects conducted as a faculty member at IIT Bombay. The content is intended solely for thought leadership and knowledge sharing. The views expressed do not necessarily represent those of IIT Bombay.