---
title: "Short note: Tower cranes"
subject: "Construction Management"
chapter: 4
key: "semester_8/construction_management:tower-cranes-note"
source: https://www.bctengineer.com/q/semester_8/construction_management/tower-cranes-note
site: BCT Engineering
---

# Short note: Tower cranes

Construction Management · Chapter 4: Familiarization with Construction Equipments

- Asked in: 2070 Bhadra, 4 marks; 2065 Baisakh (old course) (asked 2 times)
- Video: [How Tower Cranes Climb Themselves](https://www.youtube.com/watch?v=0hdv59XJ3tc) — Law & Business
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/construction_management/tower-cranes-note
- Whole chapter: https://www.bctengineer.com/md/semester_8/construction_management/chapter-4

## Question

Write a short note on tower cranes.

## Short answer

A tower crane has a vertical mast and horizontal jib balanced by a counter-jib and counterweight; it lifts, trolleys loads along the jib, and slews 360 degrees. Types include static, travelling, self-erecting, climbing, hammerhead and luffing-jib. It serves high-rise construction but needs strong foundation and is wind-sensitive.

## Answer

A **tower crane** is a fixed or climbing crane with a tall vertical mast (tower) and a horizontal jib, balanced by a counter-jib and counterweight. It is the main lifting machine for high-rise buildings.

```text
       counter     jib (boom)
       weight  ____________________
         [#]--|__trolley__|--hook
              |
              | mast (tower)
              |
         [========] base / tie to building
```
#### Parts
Base (fixed on a concrete foundation or on rails), mast sections, slewing unit with the operator cab, jib with trolley, counter-jib with counterweight, hoist rope and hook.

#### Working
The hoist lifts the load, the trolley moves it along the jib, and the slewing ring rotates the jib through 360 degrees. Capacity depends on the radius (the load moment is limited).

#### Types
Static (fixed), travelling (rail-mounted), self-erecting (small), climbing (tied to or climbing inside the structure), hammerhead and luffing-jib types.

#### Uses and merits
Lifts steel, formwork, concrete skips, precast units and materials to height; large reach and height; high speed. Limitations: high cost of erection, needs a strong foundation, and is affected by wind.

## Check yourself

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

1. What is the counter-jib counterweight for?
   A. Drives the hook
   B. Holds the foundation
   C. Supplies power
   D. Balances the jib and load
   Answer: D. The counter-jib and counterweight balance the horizontal jib. (Key point: Counterweight)

2. How does tower crane capacity vary?
   A. It increases with radius
   B. It depends only on colour
   C. It depends on radius since the load moment is limited
   D. It is constant
   Answer: C. Capacity falls with radius as the load moment is limited. (Key point: Capacity vs radius)

3. Which motion moves the load along the jib?
   A. Climbing
   B. Slewing
   C. Trolley
   D. Hoist
   Answer: C. The trolley moves along the jib; hoist lifts; slewing rotates. (Key point: Working motions)

4. Which is a limitation of tower cranes?
   A. Low height
   B. Needs strong foundation, high erection cost and is affected by wind
   C. Slow speed only
   D. Cannot be used in high-rise
   Answer: B. They need strong foundation, are costly to erect and are wind affected. (Key point: Limitation)