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Short note: 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.

Write a short note on tower cranes.

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.

       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.

✓ Answer checked by Claude Opus 5.5 (high effort)

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