EQUIPMENTS FOR ERECTION AND COMPACTION

EQUIPMENTS FOR COMPACTION Compaction is the process where by material particles are constrained to pack more closely together through a reduction of air void content generally by mechanical means

Types of compactors static smooth wheeled rollers sheep foot or pad foot rollers pneumatic tyred rollers vibratory rollers Tamper and vibrating plates

Static smooth wheeled rollers Rollers used with or without ballast Not effective on uniformly graded sand, gravel or silt and on over moist cohesive soil. Rely on weight alone to compact the material over which they pass The unit of 80 to 10 tonnes imparting pressure of 20 to 40 kg per linear cm are generally used. Lighter rollers of weight up to 1 ton are also available.

Sheepfoot or padfoot rollers Self driven or tractor driven Suitable on cohesive soils specially when water content is on the higher side. Higher degree of compaction at faster rate.

Sheepfoot roller

Pneumatic-tyred rollers Used for both in earthwork and bituminous road construction. Produce more even compaction across the rolling width than wide steel wheel smooth rollers Eliminate surface cracking and material crushing on bituminous wear courses Produce an almost sealed finish Weigthts ranging 6-30 tonnes with kg per tyre Tyre pressure 2-8 kg/sq.cm

Rubber pneumatic tyred roller

Vibratory rollers Eccentric weights within the rolls produce vibration Particles of material brought closer together as air voids eliminated Very effective on free draining type soil and granular base course Not effective on uniformly graded sand, gravel or silt. Effective pressure around twice the static weight of the roller.

Tamper and vibrating plates Used to tamp footing, trench bottom, position posts, lay paving slabs or in any small areas. Operational weights fall approximately 80kg for tamper 300 for vibrating plates. Deliver blow per min H.P powered engine

Static compaction equipment towed static smooth compactors static sheep foot or pad foot compactors static three wheel self propelled compactors static tandem compactors three axle static compactors

Spike rollers flat head tamping roller,

Vibratory compaction equipments a) Tandem vibratory compactors b) Towed vibratory compactors c) Towed sheep foot and tamping foot vibratory compactors d) Self propelled vibratory compactors e) Hand guided vibratory compactors

Tandem vibratory compactors  Dual dive or single axle dive  Available in two type: Sngle drum vibrating Both drum vibrating  double drum vibrator have 80% increased output than to single drum vibrator

Towed vibratory compactor Used for compaction of cohesive soils fine and coarse grained mixed soil, and rocky materials. Heavy towed vibratory compactors are used for the compaction of extremely thick layers(in dam or embankment construction)

Towed sheepfoot or tamping foot vibratory compactors Used for compaction of highly cohesive soil Kneading and crushing effect improves the compaction performance. Depending on the shape of foot: sheepfoot vibrator or tamping foot vibrator Sheepfoot rolls: cylindrical shape foot, small contact area Tamping foot rolls: larger contact area

Self propelled vibratory compactors Large varieties available 8-12 tons dead weight Some of job condition : Large vibratory steel roll in the front and two rubber tyres in the rear. The rubber tyres may either be smooth one for bituminous work or having thread for earth compaction work. Front roll (drum ) may be smooth, padded, sheep foot or rubber coated. Vibratory steel roll in the front and two static steel rolls in the rear for multipurpose work.

Handguided vibratory compactor These may be either, Single drum: vibrate with operator guiding behind Duplex drum: one or both drum vibrating Less than 1m width Excellent gradability and cross-country mobility Used for : trenches, slopes, parking lots, small repair jobs, sport centres, inside building and other confined spaces, and preparing foot and bicycle paths

Erecting equipments Operation of lifting a weight from one location and moving it to another location which is at a reasonable distance and then dumping it.

cranes Mobile crane

Cranes can classified into following classes 1. Derrick cranes 2. Mobile cranes 3. Hydraulic cranes 4. Overhead cranes 5. Traveller cranes 6. Tower cranes

Derrick cranes Consist of : a mast, a boom, bull wheel on which it rotates Supporting membrane Used : construction projects, plant erection, loading and unloading of cargoes, ship building etc. Boom can revolve through 360 Bullwheel attach mast and rotate Operated by diesel engine or by electric motor

Some time mounted on rail wagon for quick transport and are known as whirler Capacities 40tones with 25m boom length and 15m work radius

Mobile cranes Either crawler mounted or wheel mounted Crawler mounted: -ability to operate unmade ground -low ground bearing pressure -move slowly - used in tough terrain -economically used where ground conditions are poor and operate in a limited area

Wheel mounted crane: -high mobility -can travel upto 70-75km per hr -designed for long distance travel -operate on firm ground Mobile cranes have four motions: hoisting, dericking, slewing and traveling.

Hydraulic cranes Operation are hydraulically powered including extension Retraction of out-riggers, extension and shortening of boom Power generated by rotary oil pumps Quick change of boom length and easy and quick change of angle Beside operation of hoisting slewing and derricking can be performed simultaneously

Overhead ( gantry) crane Used for handling loads over a long rectangular area Supported on tram wheel and can move on gantry rails These are widely used in erection Consist of two main part bridge and crab Crab consist of hoisting gear mounted on a frame Frame mounted on another set of wheels and capablw of moving across the main girder

Traveller (or goliath) cranes Crabs moving on girders supported on legs Legs moves on tracks laid on floor Useful as docksite crane

Tower crane Mounted on steel tower Used in various construction projects Its constructed for work and then dismantled Truss structure Ladders are provided inside the whole height Operation cabin is provided Saddle moves horizontally and controlled from the hook block