---
title: "Short note: components of a bridge"
subject: "Transportation Engineering II"
chapter: 5
key: "semester_7/transportation_engineering_ii:short-note-bridge-components"
source: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/short-note-bridge-components
site: BCT Engineering
---

# Short note: components of a bridge

Transportation Engineering II · Chapter 5: Introduction to Bridge and Tunnel Engineering

- Asked in: 2070 Chaitra (old course), 4 marks
- Video: [Type of Bridges and its components](https://www.youtube.com/watch?v=0JLzly8mj7w) — Gurukul of Civil Engineers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/short-note-bridge-components
- Whole chapter: https://www.bctengineer.com/md/semester_7/transportation_engineering_ii/chapter-5

## Question

Write a short note on components of a bridge.

## Short answer

A bridge has a superstructure (deck slab, wearing coat, girders, cross girders, kerbs, footpaths, railings, expansion joints) and a substructure (piers, abutments, wing walls, foundations below scour depth). Bearings transmit loads and allow movement; approach slabs and protection works complete the bridge.

## Answer

A bridge consists of a **superstructure**, which carries the traffic, and a **substructure**, which transfers the load to the ground.

**Superstructure**
- **Deck slab with wearing coat**, carrying the traffic loads.
- **Main girders** (RCC, PSC or steel) or a truss/arch, with **cross girders** for lateral load distribution.
- **Kerbs, footpaths, railings/parapets**, expansion joints and drainage spouts.

**Bearings** between the superstructure and substructure transmit the reactions and permit rotation and thermal movement.

**Substructure**
- **Piers:** intermediate supports with a pier cap.
- **Abutments:** end supports that retain the approach fill; **wing/return walls** retain the earth.
- **Foundations:** footings, piles, wells or caissons, taken below the scour depth.

**Others:** approach slab and embankment, guide bunds, apron and protection works. Loads and dimensions follow IRC:6, IRC:5 and the Nepal DoR bridge standards.

```text
  Railing  Deck + girders     Railing
  ____________________________
 |Abutment|__Bearing__|Pier|Abutment|
  Wing wall  HFL ~~~~~~~  Wing wall
  Foundation below scour level
```

## Check yourself

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

1. Which is part of the superstructure?
   A. Deck slab with wearing coat and main girders
   B. Pier
   C. Abutment
   D. Well foundation
   Answer: A. The deck and girders sit above the bearings. (Key point: Superstructure)

2. Bearings permit:
   A. No movement
   B. Rotation and thermal movement
   C. Only scour
   D. Only river flow
   Answer: B. They transmit reactions and permit rotation and thermal movement. (Key point: Bearings)

3. Piers differ from abutments because piers are:
   A. End supports retaining fill
   B. Intermediate supports with a pier cap
   C. Part of the deck
   D. Protective works
   Answer: B. Abutments are end supports; piers are intermediate. (Key point: Piers vs abutments)

## Related in Transportation Engineering II

- [Bridge site factors and components with sketches](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Abridge-site-factors-components-sketches) — Transportation Engineering II, chapter 5
- [Bridge components sketch; river bank protection](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Abridge-sketch-components-river-bank-protection) — Transportation Engineering II, chapter 5
- [Bridge components; tunnel drainage and ventilation](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Abridge-components-tunnel-drainage-ventilation) — Transportation Engineering II, chapter 5
- [Bridge components; tunnel drainage and ventilation](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Abridge-components-tunnel-drainage-ventilation-problems) — Transportation Engineering II, chapter 5

## Related in other subjects

- [Components of a suspension bridge](https://www.bctengineer.com/question.md?key=semester_4%2Ftheory_of_structures_i%3Asuspension-components) — Theory of Structures I, chapter 7