The Story of Cranes

Modern cranes

Modern cranes come in many forms, each suited to a kind of job. Three of the most common types on building sites are tower, mobile and crawler cranes.

Tower cranes

A tower crane is the tall crane that stands beside a building under construction. It has a vertical mast, a horizontal arm called a jib, and a counterweight on the other side to balance the load. The operator sits in a cab high on the mast. Tower cranes are used for tall buildings because they reach high and cover a wide area. Many are raised in sections as the building grows, and the crane often climbs with it.

Mobile cranes

A mobile crane is mounted on a vehicle, usually a truck or a wheeled chassis, so it can drive to a site. Most have a telescopic boom that extends hydraulically. Supports called outriggers are extended to the ground to keep the crane steady. Mobile cranes are good for short jobs, such as lifting equipment onto a roof, because they are quick to set up and move.

Crawler cranes

A crawler crane runs on tracks, like a tractor, which spread its weight and let it work on soft or uneven ground. Many have a long lattice boom. Crawler cranes are used for very heavy lifts and can travel around a site with a load, so they suit bridges, industrial plants and wind turbines.

Choosing a crane