---
title: "RCC bridge failure probe team judgment"
subject: "Engineering Professional Practice"
chapter: 7
key: "semester_8/engineering_professional_practice:bridge-failure-probe-team"
source: https://www.bctengineer.com/q/semester_8/engineering_professional_practice/bridge-failure-probe-team
site: BCT Engineering
---

# RCC bridge failure probe team judgment

Engineering Professional Practice · Chapter 7: Case Studies based on Engineering Practices

- Asked in: 2074 Bhadra, 10 marks; year not given
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/engineering_professional_practice/bridge-failure-probe-team
- Whole chapter: https://www.bctengineer.com/md/semester_8/engineering_professional_practice/chapter-7

## Question

A RCC bridge was designed by the designer on behalf of the consultant. This was constructed by the reputed "A" class contractor. After the completion of the construction, traffic was allowed on the bridge. After six months of operation there were cracks in the bridge. A probe team was established by the road department. The design procedure was okay, but it was found that the quality of steel material used was not duly tested. The contractor argued that the procedure of construction was in accordance with the instruction of engineer and specification, however, the workmanship was found not as per specification. There was also lack of proper supervision by the consultant. The design load for the bridge was 20 tons. It was also reported that there happen to pass more than 20 tons vehicles also. The consultant was good friend of contractor. Being a member of the probe team, what is your judgement on the failure of this bridge?

## Short answer

Contractor is mainly responsible for using untested steel and poor workmanship; consultant is seriously at fault for failing to supervise and for conflict of interest. Road department is partly responsible for allowing overloaded vehicles, while designer is not at fault. Main cause is poor quality control, with overloading as a secondary factor.

## Answer

#### Facts and issues

A bridge designed for 20 tonnes cracked six months after opening. The design is correct, but (a) steel was used without proper testing, (b) workmanship did not meet the specification, (c) the consultant did not supervise properly and is a friend of the contractor, and (d) heavier vehicles than 20 tonnes used the bridge. Issues are quality failure, negligence, conflict of interest, and public safety.

#### Judgement on each party

| Party | Finding | Basis |
|---|---|---|
| Contractor | Mainly responsible | Used untested steel and poor workmanship. Following the engineer's instruction does not excuse failing to meet the specification, because the contract binds the contractor to the specified quality and to test materials. |
| Consultant | Seriously at fault | Failed to supervise, to witness tests and to reject defective work; the friendship with the contractor is a conflict of interest and he should have declared it. This is professional negligence. |
| Road Department (client) | Partly responsible | Allowed overloaded vehicles; no load limit signs or weighing control; may have weak monitoring of consultant and contractor. |
| Designer | Not at fault on the evidence | Design procedure was found correct. The load limit should have been communicated to the department. |
| Overloading vehicles | Contributing factor | A bridge has a factor of safety, so slight overload alone seldom causes cracks in six months; it aggravates already weak construction. |

The main cause is therefore poor quality of material and work that was not controlled, with overloading as a secondary cause.

#### Ethical and legal points

- The engineer's first duty is the safety and welfare of the public; the Nepal Engineering Council code of conduct requires competence, honesty, avoiding conflict of interest, and no favour to a friend.
- The contractor and consultant owe a contractual duty, and a duty of care in tort (negligence), to the client and the road users.
- Under the Public Procurement Act 2063 and the contract, the contractor is liable during the defect liability period; the performance security and retention can be used, and a poor performer can be blacklisted.

#### Recommendations of the probe team

1. Test the steel and concrete (coring, rebound, load test), and check the cause of cracks before deciding on repair or rebuilding.
2. The contractor should repair or reconstruct at own cost during the defect liability period.
3. Take action against the consultant (recover damages, report to the Nepal Engineering Council for disciplinary action, remove from the list of consultants if proved).
4. The department should set load limits, put signs and restrict overloaded vehicles, and improve supervision in the future.
5. Restrict traffic on the bridge until it is declared safe.

## Check yourself

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

1. The contractor argued that he followed the engineer's instructions. Why does this not excuse him?
   A. Because the contract binds him to the specified quality and testing of materials, not merely the engineer's instruction
   B. Because contractors are never allowed to follow instructions
   C. Because the engineer's instruction is always illegal
   D. Because the client did not sign the instruction
   Answer: A. The contractor is bound to the specification and to test materials; following instructions does not excuse untested steel and poor workmanship. (Key point: Contractor's responsibility)

2. Why is the consultant's friendship with the contractor an ethical issue?
   A. Friendship between engineers is banned by law
   B. It is a conflict of interest that should have been declared, and it weakened supervision and rejection of defective work
   C. It proves the consultant designed the bridge wrongly
   D. It makes the client responsible for the cracks
   Answer: B. Friendship with the contractor is a conflict of interest the consultant should have declared; he failed to supervise, witness tests and reject defective work. (Key point: Conflict of interest of the consultant)

3. How does the answer treat overloading by vehicles above 20 tonnes?
   A. It is the main cause of the cracks
   B. It is irrelevant
   C. It is the designer's fault
   D. A contributing factor: with a factor of safety, slight overload alone seldom cracks a bridge in six months, but it aggravates weak construction
   Answer: D. A bridge has a factor of safety, so overload is secondary; the main cause is poor material and uncontrolled work. (Key point: Role of overloading)

4. Which is a recommendation of the probe team?
   A. Open the bridge fully to prove it is safe
   B. Let the department repair at its own cost without recovery
   C. Blame the designer since the bridge cracked
   D. Test steel and concrete, have the contractor repair at own cost in the defect liability period, and restrict traffic until declared safe
   Answer: D. The team should test materials and find the cause, make the contractor repair at its cost, act against the consultant, set load limits and restrict traffic until safe. (Key point: Probe team recommendations)

## Related in Engineering Professional Practice

- [Bheri river suspension bridge collapse](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Abheri-suspension-bridge-collapse) — Engineering Professional Practice, chapter 7
- [Unpaid sub-contractor beaten by labourers](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Asubcontractor-unpaid-labour-case) — Engineering Professional Practice, chapter 7
- [Slippery floor injures consultant engineers](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Aslippery-floor-injury-blame) — Engineering Professional Practice, chapter 7
- [Contractor asks supervisor to prepare running bill](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Acontractor-running-bill-bribe) — Engineering Professional Practice, chapter 7
- [Building near river bank; stop construction?](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Abuilding-on-river-bank-flood) — Engineering Professional Practice, chapter 7
- [Site engineer uses weaker mortar and concrete mix](https://www.bctengineer.com/question.md?key=semester_8%2Fengineering_professional_practice%3Amortar-ratio-friend-silence) — Engineering Professional Practice, chapter 7

## Related in other subjects

- [Client, consultant and contractor relationship](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Aclient-consultant-contractor-relation) — Construction Management, chapter 1, asked 6×
- [Two roles each of client, consultant, contractor](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Aroles-client-consultant-contractor) — Construction Management, chapter 1
- [Consultant and quality of construction works](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Aconsultant-role-quality) — Construction Management, chapter 1
- [Bill of quantities for RCC T-beam bridge](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aboq-rcc-t-beam-decking) — Estimating and Costing, chapter 2