A crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple to create mechanical advantage and thus move loads beyond the normal capability of a human.
Main Basic Lifting Parts Of The Crane: Lever Pulley The hydraulic cylinder A balance crane contains a horizontal beam (the lever) pivoted about a point called the fulcrum. A jib crane contains a tilted strut (the jib) that supports a fixed pulley block. Cables are wrapped multiple times round the fixed block and round another block attached to the load. For stability, the sum of all moments about any point such as the base of the crane must equate to zero.
On the basis of modern crane study and advancement there are two basic types of cranes:-A). Fixed craneB) Mobile or movable crane A fixed crane is the type of crane which lift the loads without any appreciable movement. A mobile crane is the type of crane which moves from one place to another as well as movement of the crane basic tools.
1.TOWER CRANEThe tower crane is a modern formof balance crane. Fixed to the ground (andsometimes attached to the sides ofstructures as well), tower cranes often givethe best combination of height and liftingcapacity and are used in the construction oftall buildings.
Specification of tower crane:-Lifting Capacity: max 25tWorking Radius: 70 m to75mTower crane is generally usedfor high rise infrastructure andproject
Specification:-Lifting Capacity: max 6t to 8tWorking Radius: 45mUse:It is mainly used on construction –site to transport the material fromone place to other place.
The "hammerhead", or giant cantilever,crane is a fixed-jib crane consisting of asteel-braced tower on which revolves alarge, horizontal, double cantilever; theforward part of this cantilever or jibcarries the lifting trolley, the jib isextended backwards in order to form asupport for the machinery and counter-balancing weight.Specifications:-Lifting capacity –max 350tonsWorking radius-up to 70mUse: Ship-yard work includingconstruction of ship and heavy dutybuilding construction.
This type of crane is similar to the bridge crane except that it runs on a runway at the floor level. The bridge is supported by a pair of rigid steel legs which are carried by a pair of end trucks along the floor level runway.
Specifications:-Lifting Capacity: 5 tones to 10 tonesWorking Radius: 23 mUse: In the construction of Bridgesuperstructure for lifting heavy girder. In Ship manufacturing industry ,for liftingheavy parts of ships.
Overhead Crane can build top running cranes, under running cranes, double girder cranes, and single girder cranes ranging from: Capacities - 1/4 ton through 100 tons Spans - 5 through 125„ Use: The most common overhead crane use is in the steel industry.
Located near sea shore, these are used for cargo operations or boat unloading and retrieval where no shore unloading facilities are available. Lifting Capacity:25 to 36 tones Working Radius: 20m to 30m
This type of crane consists of a pivoting head and boom assembly which carries a hoist and trolley unit. Lifting Capacity: 1 to 300 tones Working Radius: 70m Use: Jib crane used in ship yards for lifting heavy machinery and equipment, weighing 100 to 300 tons.
Bulk-handling cranes are designed from the outset to carry a shell grab or bucket, rather than using a hook and a sling. They are used for bulk cargoes, such as coal, minerals, scrap metal etc. Lifting capacity: 120 tones Working Radius: 56m
1.TRUCK MOUNTED CRANE It is the cranes mounted on a rubber tire truckwill provide great mobility. Lifting capacity: 20 to 30 tones Working Radius: 15m to 20m Use: It is used for the loading and unloading of motor vehicle rolling stock, for cargoes primarily of a heavy and single-item nature, and also for construction and repair work.
A side lift crane is another type of movable crane able to transport materials and hoist large containers. Very large containers are lifted using a pair of side lift cranes. Lifting Capacity: 120 US tones Working Radius: 50m
Rough terrain crane is a crane mounted on an undercarriage with four rubber tires that is designed for pick-and-carry operations and for off-road and "rough terrain" applications. Lifting capacity:200 tons at 3m working radius The rough terrain crane is used for building bridges, operations in power and chemical plants and refineries and for large- scale projects.
A mobile crane with the necessary equipment to travel at speed on public roads, and on rough terrain at the job site using all-wheel and crab steering. AT„s combine the road ability of Truck-mounted Cranes and the maneuverability of Rough Terrain Cranes. Lifting capacity: up to 300 tons Working radius: 34m Our all-terrain mobile cranes are excellent for use in places where ground is uneven or not very accessible like a beach or a rocky expanse.
A crawler crane is a crane mounted on an undercarriage with a set of tracks (also called crawlers) that provide stability and mobility. Lifting capacity from about 35 to 40 tones This particular asset class is ideal for working in confined or small area where a big crane can not reach. Crawler crane command their position at many of power plants, thermal plants and at big infra projects. These crane are well suited for piling, drilling and pipe laying operation by just adding suitable attachment.
Rail road crane is one of the mobile crane type. The name tells us that this crane runs on rail tracks. A railroad crane is specifically designed with flanged wheels so it can travel along railroad tracks. Although the design differs according to the type of work, the basic configuration is the same in all cases which is a rotating crane body is mounted on a sturdy chassis fitted with flanged wheels. Uses:1.For lifting the goods at station yards.2. It may be used for installing signalling equipment or pointwork, for example, while more specialised types are used for track laying.
Floating crane is one mobile crane, they are sea vessels have crane mounted on them or ships equipped with cranes but not like deck crane. They are mainly used in building bridges and port construction. They are capable of carrying whole sections of bridge through the water and installing it in position due to their loads capacity which exceeds 10,000 ton their capacity of loading is great. Floating cranes are the ideal choice for cargo handling on waterways . Floating crane are mobile and can be used in rivers (mid-stream transshipment), in ports, in protected waters, in coastal waters and on the open sea.
Aerial cranes are helicopters used for lifting weights. they are one of the mobile crane type. Also they are called sky cranes. These helicopters lift the loads by its long cables. They are used in remote and accessible places where it is very hard to get any crane type. These places like buildings tops, hill or mountain top and other places that cost a lot of money and time to get any other crane like telescopic or tower crane. The aerial cranes are economical and quick in their work, but nothing is all good, they also have some disadvantages, like the load limit they can lift and the skills needed near this crane.
The main causes of crane failure are listed as:1.Struck by Load2.Electrocution3.Crushed During Assembly/Disassembly4.Failure of Boom/Cable5.Crane Tip Over6.Struck by Cab/Counterweight7.Falls
Periodically read the manual and review the rules. Examine the load chain for damage or twists, or the wire rope for kinks or fraying. Check the hook. If its out of shape, dont use it. This may indicate internal damage. Avoid shock loads. Dont run the hook with a slack chain. Bring the chain or wire to a taut position before lifting. To avoid damage to the hoist, the rope or chain should always be in a straight line from hoist to hook. Avoid snagging a load while lifting. Avoid jogging a load. When using a wire rope hoist, check the wire on the drum. Dont let it get out of the grooves and pile upon itself.
Side pulls with a wire rope hoist may fray the ropeand make it unsafe and/or damage the hoist.Never leave a suspended load unattended. That loadis your responsibility. Never carry a load over another person...or getunder a load yourself.Never lift people with a hoist. When moving a load, look where you are going.Push, dont pull.
A crane is heavy mechanical equipment, which is used for lifting the heavy materials. After this studied we conclude that, crane plays a vital role in the construction industry, and makes the construction faster and economical. This paper investigates crane safety in related to the understanding and degree of executing statutory requirements and non-statutory guidelines for the use of cranes After the study of it we know about crane and their uses in different places. This presentation gives the information about the causes of failure and the preventive measures.
Al-Hussein. (1995). “A compute Integrated System for crane selection for High Rise Building Construction, M.A.Sc. Thesis, Centre For Building Studies, Concordia A journal of “Civil engineering & construction review” July 2012 pg.no.62-84 ASCE (2002)Adaptive Probabilistic Neural Network Based Crane Type Selection System “Journal of construction Engineering and Management.” Vol.(128):265-273