Structural Stability & NDT Assessment of G+2 School Building

Scope of Investigation

The investigation combined visual inspection and non-destructive testing to assess concrete condition, uniformity, durability indicators and reinforcement details in selected structural elements.

• Visual inspection of structural elements
• Rebound Hammer Test
• Ultrasonic Pulse Velocity (UPV) Test
• Concrete Carbonation Test
• Profometer and reinforcement detection testing
• Assessment of concrete quality and uniformity
• Measurement of concrete cover and reinforcement arrangement
• Preparation of technical findings and recommendations

Visual Inspection

The structural elements were visually inspected for apparent signs of distress. No visible cracks were recorded in the inspected columns, beams and slabs, and the concrete was reported to be in good observed condition in the inspected structural elements.

A small crack was observed in one portion of the stair-head wall. The reported dimensions of the inspected structural elements were consistent with the approved drawings.

Rebound Hammer Testing

Rebound Hammer testing was conducted at selected locations to obtain an indication of concrete surface hardness and estimated compressive strength.

The recorded estimated compressive-strength values ranged approximately from 16 to 34 N/mm² at the tested locations. The report references IS 13311 (Part 2):1992 for the Rebound Hammer assessment.

Rebound Hammer results are surface-based indicators and should be interpreted alongside other investigation results rather than treated as a standalone determination of structural capacity. The report also notes the limitations and variability of this method.

Ultrasonic Pulse Velocity Testing

Ultrasonic Pulse Velocity (UPV) testing was performed to assess concrete uniformity and identify locations that may contain internal discontinuities.

The tested locations received GOOD, MEDIUM and DOUBTFUL classifications. The recorded results helped identify specific structural elements requiring closer attention during the assessment.

• Column N1 — 3.831 km/s — GOOD
• Column N5 — 2.932 km/s — DOUBTFUL
• Column N7 — 2.841 km/s — DOUBTFUL
• Slab N2 — 4.240 km/s — GOOD
• Beam N1 — 2.421 km/s — DOUBTFUL
• Column N14 — 2.354 km/s — DOUBTFUL

Carbonation Assessment

Carbonation testing was conducted to assess the extent of carbonation in the concrete cover. The report records the carbonation condition as low to mild and indicates that the reinforcement remained within the passivation zone at the tested locations.

Reinforcement & Concrete Cover Assessment

Profometer testing was performed to identify approximate reinforcement locations, bar diameters, bar spacing, stirrup arrangements and concrete cover.

Selected column measurements recorded concrete cover values of approximately 36–44 mm. Reinforcement percentages were documented in the report with reference to the applicable provisions cited therein. Similar reinforcement and cover information was obtained for selected beams and slabs.

Key Assessment Findings

The investigation provided a combined assessment of the visible condition of the structural elements, concrete surface characteristics, internal concrete uniformity, carbonation and reinforcement details.

Visual inspection provided information about observable defects, while Rebound Hammer testing assessed surface hardness and UPV testing helped identify variations in concrete uniformity. Carbonation testing provided a durability indicator, and Profometer testing supplied approximate reinforcement and cover information.

Together, these methods helped distinguish satisfactory test locations from specific areas requiring further attention.

• Visible condition of columns, beams, slabs and walls
• Concrete surface characteristics from Rebound Hammer testing
• Internal concrete uniformity from UPV testing
• Carbonation condition at tested locations
• Reinforcement arrangement and concrete cover from Profometer testing

Technical Conclusion

Based on the findings documented in the report, the majority of the tested concrete elements were classified between medium and good condition by UPV testing, while certain locations were classified as doubtful.

The report identified the doubtful locations as requiring appropriate repair or attention. Its final conclusion states that the assessed structure was considered satisfactory in terms of the investigated strength and durability parameters, subject to minor repair of the doubtful elements.

Our Approach

VISUAL INSPECTION → NDT TESTING → DATA ANALYSIS → CONDITION ASSESSMENT → TECHNICAL RECOMMENDATIONS

Nilima Design Associates combines field inspection, multiple NDT techniques and engineering interpretation to develop a documented understanding of existing structural conditions and identify areas that may require repair or further investigation.

• Visual inspection of accessible structural elements
• Selection and application of appropriate NDT techniques
• Review of test results and observed defects
• Assessment of concrete condition and reinforcement details
• Technical reporting and recommendations

Project Value

This project demonstrates Nilima Design Associates' experience in carrying out structured, evidence-based investigations of existing RCC buildings using a combination of visual inspection and Non-Destructive Testing techniques.

The assessment provided the client with documented findings on concrete condition, uniformity, carbonation and reinforcement details, helping identify specific areas requiring attention.

Need an Assessment of an Existing Building?

Nilima Design Associates provides structural inspection, NDT testing, structural health assessment and technical reporting for residential, commercial, institutional and industrial structures.