A number of machines and vehicles are used on a building site. Bulldozers, diggers and dump trucks are used to clear away any old buildings, rubble and earth, and to level the site. Pile drivers, huge mechanical hammers, are used to drive supporting pillars, called piles, into the ground. Concrete mixers mix concrete to make foundations. Tower cranes lift steel girders and concrete slabs to the upper floors as the building goes up.

Dumper truck

The dumper truck has huge wheels and a powerful engine. These enable it to carry very heavy loads. To dump its load, the truck body tips up, the tailgate at the back swings open and the rubble slides out. Large dumper trucks, used in big construction and mining projects, are called haul trucks.

A tower crane lifts heavy building materials into place, for example, steel girders to the upper floors. These will make up the building’s frame. Concrete slabs, which form the floors and walls, are also lifted by the crane. The crane's hook, which carries the load, moves along its arm, or jib. The driver operates the crane from the cab. A heavy concrete counter-weight at the back of the crane balances the weight of the load being lifted.