CONSTRUCTION EQUIPMENT

-HOISTING EQUIPMENT

FRANKLIN P DKAUSTUBH DHOBE

INTRODUCTION Hoisting is the lifting a weight from one location

and moving it to another location which is at a reasonable distance.

Big projects such as, construction of dams, industrial buildings etc. require hoisting equipment.

Hoisting equipment includes jacks, winches, chain hoists and cranes.

Crane is the only single machine which, as a single piece, is capable of providing three-dimensional movement of a weight.

CRANE A crane is a type of machine, generally equipped

with a hoist rope, wire ropes or chains, and sheaves,

It can be used both to lift and lower materials and to move them horizontally. It is mainly used for lifting heavy things and transporting them to other places.

It uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a human.

MECHANICAL PRINCIPLE

Major considerations in the design of cranes.  the crane must be able to lift the weight of the

load; second. the crane must not topple. the crane must not rupture.

The Principles involved are Lifting capacity Stability

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.

TYPES OF CONSTRUCTION CRANES

1) Mobile cranes2) Fixed cranes

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.

MOBILE CRANES The most basic type of mobile crane consists

of a truss or telescopic boom mounted on a mobile platform be it on road, rail or water. Common terminology is conventional and hydraulic cranes respectively.

These cranes are mounted on mobile units which is either crawler type or wheel type.

TYPES OF MOBILE CRANES

1) Truck mounted crane

It is the cranes mounted on a rubber tire truck will provide great mobility.

The truck cranes have a self-contained telescoping boom.

In case of larger machines, the width of the out triggered vehicle may reach 40ft.

Common dimensions and capacity:1) Max Boom length : 70 to 170 ft2) Maximum fly-jib length : 30 to 100ft3) Maximum radius (boom only) : 60 to 140 ft4) Minimum radius : 10ft 5) Maximum lifting capacity : 20 to 120 ton6) Maximum travel speed : 40 to 70 mph7) Number of axles : 3 to 4

2) Lattice-Boom truck –mounted cranes

Lattice boom structure is light weight.

Reduction in boom weight means additional lift capacity, as the machine predominately handles hoist load and less weight of boom.

It does take long time to assemble.

Common dimensions and capacity:1) Max Boom length : 170 to 470 ft2) Maximum fly-jib length : 40 to 300ft3) Maximum radius (boom only) : 130 to 380 ft4) Minimum radius : 10 to 25ft 5) Maximum lifting capacity : 50 to 600 ton6) Maximum travel speed : 40 to 60 mph7) Number of axles : 4 to 8

3) Rough terrain cranes 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.

It can move on slopes upto 70%.

Most have 4 wheel drive and 4 wheel steering which allows them to traverse tighter and slicker terrain than a standard truck crane with less site preperations.

Common dimensions and capacity:1) Max Boom length : 80 to 140 ft2) Maximum fly-jib length : 20 to 90ft3) Maximum radius (boom only) : 70 to 120 ft4) Minimum radius : 10ft for most of the models5) Maximum lifting capacity : 20 to 90 ton6) Maximum travel speed : 15 to 35 mph7) Number of axles : 2 for all models

4) All terrain cranes

Designed with an undercarriage capable of long distance of long distance highway travel.

Yet the carrier has all-axle drive and all wheel steering. Crab steering, large tires and High ground clearance.

Has dual cabs, a lower cab for fast highway travel and a super structure cab that has both drive and crane controls.

Common dimensions and capacity:1) Max Boom length : 100 to 270 ft2) Maximum fly-jib length : 30 to 240ft3) Maximum radius (boom only) : 70 to 250 ft4) Minimum radius : 8 to 10ft5) Maximum lifting capacity : 30 to 300 ton (max. 800ton)6) Maximum travel speed : 40 to 55 mph7) Number of axles : 2 to 6 for (upto 8 or 9)

5) Crawler crane

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.

6)Railroad crane 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.

7) Floating crane 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.

Tipping conditionWhen a crane lifts a load attached to the hoist line

that passes over a Sheave located at the bottom point of the machine, there is a tendency to tip the machine over.

Tipping load – The load that produces a tipping condition at a specific radius.

A Partial safety factor with respect to tipping is introduced by PCSA

1) Crawler-mounted machines = 75% 2) Rubber-tire mounted machines =85% 3) Machines on outriggers = 85%

Load capacity will vary depending on the quadrant position of the boom with respect to machine’s under carriage.

In case of crawler cranes, 1) Over the side

2) Over the drive end of the tracks 3) Over the idler end of the tracks

In case of wheel mounted cranes,1) Over the side2) Over the rear of the carrier3) Over the front of the carrier

Factors that will affect actual crane capacity on the job

1) Wind forces on the boom or load2) Swinging the load3) Hoisting speed4) Stopping the hoist

TOWER CRANESTower cranes are a modern form of balance

crane that consist of the same basic parts. Fixed to the ground on a concrete slab (and sometimes attached to the sides of structures), tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings.

Fixed to the ground. Horizontal boom is balanced asymmetrically. Short arm carries a counterweight of concrete blocks. Long arm carries the lifting gear.

COMPONENTS Mast: The main supporting tower of the crane. It is made of steel

trussed sections that are connected together during installation. Slewing unit: The slewing unit sits at the top of the mast. This is the

engine that enables the crane to rotate. Operating cabin: The operating cabin sits just above the slewing

unit. It contains the operating controls. Jib: The jib, or operating arm, extends horizontally from the crane. A

"luffing" jib is able to move up and down; a fixed jib has a rolling trolley that runs along the underside to move goods horizontally.

Counter jib: holds counterweights, hoist motor, hoist drum and the electronics.[41]

Hoist unit: The hoist unit houses the hoist drum, hoist cable, gear box, gear shift, brake, and supporting components.

Hook: The hook (or hooks) is used to connect the material to the crane. It hangs at the end of thick steel cables that run along the jib to the motor.

Weights: Large concrete counterweights are mounted toward the rear of the mast, to compensate for the weight of the goods lifted

TOP SLEWING TOWER CRANE

Common dimensions and capacity:1) Jib length : 100 to 270 ft2) Mast section length : 10 to 20ft3) Base dimensions : 13x13 ft to 27x27 ft4) Tower cross section : 4x4 ft to 8x8 ft 5) Maximum lifting capacity : 10 to 90K lb6) Maximum lifting capacity at end of jib : 2 to 13k

lb 7) Maximum hoisting speed : 150 to 500 ft/min8) Maximum trolleying speed : 100 to 350 ft/min9) Maximum slewing speed : 0.6 to 1.0 rpm

BOTTOM SLEWING TOWER CRANE

Common dimensions and capacity:1) Jib length : 70 to 150 ft2) No. of telescoping/ folding mast parts : 2 to 33) Base dimensions : 10x10 ft to 15x15 ft4) Total towed transport length : 30 to 50ft 5) Maximum lifting capacity : 2 to 18K lb6) Maximum lifting capacity at end of jib: 1 to 5k lb 7) Maximum trolleying speed : 60 to 200 ft/min8) Maximum slewing speed : 0.8 rpm

Self-Erecting Tower CranesGenerally a type of pedestrian operated tower crane, these cranes, also called self-assembling, jack-up, or "kangaroo" cranes, lift themselves from the ground or lift an upper, telescoping section using jacks, allowing the next section of the tower to be inserted at ground level or lifted into place by the partially erected crane itself. They can thus be assembled without outside help, and can grow together with the building or structure they are erecting.

Travelling Tower Cranes The ballasted base of

this type of tower crane is set on a pair of fixed rails .

This enables the crane to move along the rails with a load.

Increased coverage of the work area cab be achieved.

Tower Crane selection Based on 1) Weight, dimension and lift radii of the heaviest loads.2) Maximum free standing height of the crane.3) Maximum braced height of the crane.4) Crane climbing arrangement.5) Weight of crane supported by the structure.6) Available Headroom.7) Area that must be reached.8) Hoist speeds of the crane.9) Length of cable the hoist drum can carry.

REFERENCES 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

Construction Planning Equipment and Methods - Peurifoy www.uniccrane-global.com www.terex.in www.wikipedia.com www.googleimages.com

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