Self-growing construction cranes are the workhorses of the high-rise building trade. As the skyscrapers they are attached to grow so do the cranes. Raising the cranes requires planning, skilled workers and careful execution. It is a difficult and dangerous balancing act involving thousands of pounds of steel performed hundreds of feet in the air.
- Skill level:
Things you need
- Construction crane
- Mobile crane
- Experienced workers
Pour the supporting concrete pad, typically 30-by-30 feet and four-feet thick, with deeply embedded, large anchor bolts. Bring the crane pieces to the site on a dozen or so tractor trailers. Use the mobile crane to place the tower crane base on the concrete pad. Bolt it down securely with the anchor bolts, tightening the nuts with a hydraulic wrench and a force of typically 1814 Kilogram. Use a mobile crane to hoist the first section of tower onto the base and have workers bolt the section in place.
Assemble the top of the tower crane, using the mobile crane. Hoist the slewing unit, which allows the crane to rotate, and attach it to the top of the tower. Hoist the climbing frame, which allows the tower to grow, and attach it below the slewing unit. Hoist the horizontal beam or working beam and attach it on top of the slewing unit. Hoist the operator's cab and attach it in place on the horizontal beam. Hoist the machinery arm, which holds the motors and counterweights and bolt it into place on top of the slewing unit.
Unbolt the slewing unit from the top of the tower and attach it to the climbing frame which is located below the slewing unit and fits around the tower. Activate the climbing frame to lift the slewing unit with the climbing frame's powerful, hydraulic jacks. It will lift the slewing unit along with the rest of the top gear by 20 feet. Have workers attach counterweights for the lifting of another section of tower. Use the slewing unit to hoist a 20-foot section to the top of the tower and into place in the gap created by the climbing frame. Have workers bolt the new section into place at the top of the tower. If more height is required, hoist the climbing frame up one section and attach it below the slewing unit. Repeat the procedure by having the climbing frame lift the slewing unit again.
Tips and warnings
- Building a construction crane is a specialised job best carried out by experts in the field.
- Your construction company will need a building permit to start construction and a special permit to put up the construction crane. Check with local authorities about specific requirements.
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- Deckrane Services: How Tower Cranes Work
- Yes Mag: At a Construction Site for a Tall Building You See Them Using a Crane on Top of a Tall Scaffolding. How Do They Build That Scaffolding and Get the Crane Up on Top?
- Ritchiewiki: Tower Crane
- The Health and Safety Executive of Great Britain: Discussion Paper on the Safe Use of 'External' Climbing Frames on Tower Cranes