---
title: "Steps in diagnosing a structure for rehabilitation"
subject: "Construction Management"
chapter: 9
key: "semester_8/construction_management:rehabilitation-diagnosis-steps"
source: https://www.bctengineer.com/q/semester_8/construction_management/rehabilitation-diagnosis-steps
site: BCT Engineering
---

# Steps in diagnosing a structure for rehabilitation

Construction Management · Chapter 9: Project Maintenance

- Asked in: 2065 Baisakh (old course)
- Video: [lec 4- Detailed investigation](https://www.youtube.com/watch?v=QM0GCa1Y-jo) — MOHAMMEDABBAS JAMANI
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/construction_management/rehabilitation-diagnosis-steps
- Whole chapter: https://www.bctengineer.com/md/semester_8/construction_management/chapter-9

## Question

Explain the steps involved in diagnosing the problem affecting a structure for which rehabilitation is to be done.

## Short answer

Diagnosis begins with collecting background information and visual inspection of cracks, deflection, and distress. Then detailed investigation uses NDT, core and steel sampling, chemical tests, structural analysis, and cause identification. Finally, damage is classified, remedial measures are chosen, and a report with monitoring is prepared.

## Answer

Diagnosing the problem of a structure before rehabilitation follows a systematic sequence:

1. **Collect background information:** age, drawings, design and construction records, use and loading history, earlier repairs, exposure conditions, and any damaging events (earthquake, fire, flood).
2. **Preliminary (visual) inspection:** record cracks (width, pattern, location), deflection, tilting, leakage, spalling, rust stains, efflorescence, settlement and signs of distress with sketches and photographs.
3. **Plan the detailed investigation:** select the points and the tests required.
4. **Non-destructive testing (NDT):** rebound hammer, ultrasonic pulse velocity, cover meter, half-cell potential for corrosion.
5. **Partial destructive tests and sampling:** concrete cores, steel samples, mortar and soil samples; carbonation depth, chloride and sulphate tests, compression tests.
6. **Structural analysis:** reassess the load capacity of the damaged structure with actual material strengths and the geometry.
7. **Find the causes of distress:** design or construction errors, overloading, poor material, corrosion, chemical attack, settlement, thermal movement, seismic damage.
8. **Evaluate extent and severity;** classify the damage (minor, moderate, severe), and check safety and need for temporary support.
9. **Decide the remedial measures:** repair, strengthening, protection or demolition, and prepare a rehabilitation plan with materials, methods, cost and schedule.
10. **Report and monitoring:** prepare a report and install monitoring (crack gauges, tell-tales) to check the effect of the repair.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is done first when diagnosing a structure for rehabilitation?
   A. Demolish it
   B. Collect background information such as age, drawings and history
   C. Order materials
   D. Apply paint
   Answer: B. Diagnosis begins by collecting age, drawings, records, loading history and exposure. (Key point: First step)

2. Which is a non-destructive test in the sequence?
   A. Concrete core compression
   B. Steel sampling
   C. Soil sampling
   D. Rebound hammer and ultrasonic pulse velocity
   Answer: D. Rebound hammer, UPV, cover meter and half-cell potential are NDT. (Key point: NDT)

3. Which belong to partial destructive tests?
   A. Concrete cores, steel samples, carbonation and chloride tests
   B. Visual inspection
   C. Rebound hammer
   D. Photographs
   Answer: A. Cores, samples and chemical tests are partial destructive tests. (Key point: Sampling)

4. Why install crack gauges or tell-tales after repair?
   A. To decorate
   B. To check the effect of the repair
   C. To reduce load
   D. To measure rent
   Answer: B. Monitoring shows whether the repair is effective. (Key point: Monitoring)

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