Safety Management & Site Establishment Unit 11 - Site Plant - - PowerPoint PPT Presentation

Unit 11 - Site Plant Management

Safety Management & Site Establishment

This lecture aims to introduce the following;  The importance of plant for site construction works  Points to consider during negotiation of plant hires  Points to consider during selection of site plants  Main Site plant types, their capabilities and likely uses on site

Learning Outcomes

• Traditionally, most materials are manhandled, but as labour

costs rise in relation to the costs of using mechanical equipment, increased productivity will be sought on site by improved applications of machinery

• Mechanisation is one aspect of industrialisation aimed at

increasing productivity

• Whatever the strategy of mechanisation there will generally

be a reduction in the amount of labour deployed without a decline in production and an improvement in waste management.

Site Plant Management

As a group, kindly create a spider diagram for your allocated subject; 1. Fully identify the factors to be considered during the negotiation of the plant hires, 2. Fully identify the factors to be considered during the selection of site plant, 3. Fully identify the whole aspects of Hire vs. Purchase of site plant, 4. Main factors affecting efficient deployment of mechanical plant on site such as:

• the nature of job and site
• the relationship between operations of plant and of men
• the planning and programming of the contract as a whole
• the suitability of the building’s design and layout

how do each item affect the efficient deployment of mechanical plant on site?

Group Work:

Nature of job and site:

• Mechanisation is usually more viable on larger contracts, as they

normally have sufficient amount of work of varying nature spanned over significant contract duration to justify the introduction of specialised machines and to enable them to be used economically

• Site conditions must be suitable for the safe, efficient and

economic use of all plants and equipment. Relationship between operations of plant and of men:

• The number of men working on any operation should be well co-

related to the output of the mechanical plant serving them.

• This is to maximise mechanical productivity whenever possible.

Site Plant Management

Careful planning and programming of the contract as a whole:

• To ensure that all plant hired or purchased is occupied to the

maximum extent while on the site.

• Ideally, the sequence of all operations throughout the job,

whether mechanised or manual, should be so arranged that no plant on the site is ever idle. Suitability of the building’s design and layout:

• The use of mechanical plant must be carefully considered at the

planning stage, and should have been allowed for during the tender phase.

• The contractor has to be aware of the advantages of mechanised

methods that include continuity of operations and the use of plant at maximum capacity every time it is operated.

Site Plant Management

• Hiring plant and equipment for a construction site is normally

undertaken by site based staff

• It needs to be thoroughly thought through as there are many

charges, on top of the hourly or daily hire rate

• These charges can be significant when set against the basic rate

and need to be agreed up front if the best deal is to be achieved.

• Delivery Costs
• Maintenance charges
• Sale ex-hire charges
• Insurances
• Operator costs
• Service response
• Bulk discounts

Negotiation of plant hires

Delivery costs -

• All plant will be subject to delivery and up-lift charges (one-off

charges) and this will be more expensive the larger the items of plant.

• If a piece of operated plant is required on site only for a short

period e.g. a backhoe excavator for a day, then the one-off charge may be as much as 50% of the total day’s hire cost if it comes on a low-loader lorry.

• Clearly, the longer the likely hire, the less significant the one-off

cost will be.

• Even for small, hand held plant the one-off charges can be steep

compared with the hire cost and must be considered part of the hire cost equation.

Negotiation of plant hires

Maintenance charges –

• All items of plant and equipment need to be maintained and the

hirer must establish whether the hire charge includes routine maintenance

• Maintenance cost on small items of plant will be relatively low cost

and is normally included in the weekly or monthly hire rate

• However, for operated plant the hourly hire rate may not do so

and so an additional four hours a week (10%) on top of the hire rate may make the hirer less competitive than some of his rivals

Negotiation of plant hires

Sale ex hire charges –

• On construction sites, items of plant go missing and items of plant get

damaged.

• Most plant hirers expect some degradation during the hire but others do

not, so it is important to be clear on the charging liability.

• For example, hired trench sheeting is likely to be buckled and twisted

when it comes back out of the ground and a hirer will usually charge for straightening and cleaning.

• Also many very small items of plant simply get lost in the mud or pools of

water because of the conditions in which the works are being undertaken.

• Accordingly, it is always best to consider “write off” a proportion (say 5%)
• f the hired items in the first week to save paying hire charges throughout

the hire period, then in addition for losses at the end of the hire.

Negotiation of plant hires

Insurances –

• Insurance will almost always be the responsibility of the hiring

site unless the item of plant is operated and the operator actions caused the insurance loss

• Vandalism of plant and equipment has always been a problem on

construction sites, so when hiring operated plant, ensure it is fitted with protective screens as these costs will be picked up by the hirer.

Negotiation of plant hires

Operator costs –

• Hourly hire rates will normally include the wages of the plant
• perators; however, some operators will make a larger

contribution to productivity on site than others

• Often the plant operator will be included in the gang bonus

system and any costs of these bonuses will be on top of the hire charges

• These should be self financing but they may also be motivational

if the works are subject to bonus

Negotiation of plant hires

Service response –

• Another important factor to consider is the speed of service

response

• Often a gang of workers will be dependent on a machine working

throughout the day

• If the item of plant does not start or stops during the day, the

down time can result in significant lost cost on the project.

• All hirers will provide free service response but they will not cover

the disruption costs.

• It is important to select a plant hirer who provides good plant and

good service to avoid unacceptable periods of down-time

Negotiation of plant hires

Bulk discounts –

• If a lot of plant is hired then significant discounts are available if

all the plant is hired from the one hirer

Negotiation of plant hires

• Items ranging from hand-held powered tools to monumental

tower cranes can be considered for use on the following basis:

• Increased Production
• Reduction in Overall Construction Costs
• Enable activities that cannot be effectively carried out by

manual labour, saving time & costs and ensuring better quality

• Eliminate heavy manual work, thus reducing fatigue
• Improved control over consistency and quality of output

Selection of site plant

The general considerations to be assessed prior to any procurement and deployment of site plant are summarised as follows:

• Is the plant/equipment a ‘necessity’ or a ‘want’?
• Could extra labour input and/or other plants/equipment in the

company’s possession take over its role?

• Bearing the contract sum in mind, is it viable to procure the

plant/equipment solely for use in the project or as an asset?

• Will productivity on site be significantly increased?
• What is the most competitive price package to obtain equipment for

its intended use, and what are the best procurement methods (e.g. direct-purchase, hire-purchase, monthly rental…etc.)?

• A final check: Is it financially viable to even consider having the plant
• n site, knowing its mechanical output, no. of operatives required,

maintenance requirements…etc.?

Selection of site plant

• Once the site requirements are ascertained and the necessity
• f external plant procurement established, the contractor will

compare market offerings against his capabilities and needs

• A selection template should be drawn up to assist in a

systematic selection procedure

• With data derived from the tables, the contractor can then

perform a comparative analysis and decide on the option that is best suited for the requirements of his company and project

Selection of site plant

• Note that no company will have the same set of corporate

priorities and agenda

• As such, even a typical non-executive decision such as plant

selection, based on identical project requirements and market

• fferings, will tend to differ amongst the most similar of

competitors in the industry

Selection of site plant

Performance evaluation

• In order to estimate the production output of a plant, a

contractor will also be mindful of its optimal output and production-cycle commonly expected of the plant under anticipated site conditions

• This is an invaluable set of information that ideally has to be

provided by either the manufacturer or hirer

• This analysis can form a basis for estimating productivity,

taking into account the nature of task and the combined

• perational efficiency of both plant and operator

Selection of site plant

Advantages of hiring:

• Obscure/specialist plant that are usually not required by the

contractor can be hired for short periods of time

• For plant that are required over a lengthy period, costs of hire can

usually be negotiated and brought down, together with additional packages thrown in by hirer

• Plant are returned to hirer after use, thus reducing contractor’s

stockpile of equipment and its cost of storage as well

• Hirer may include the service of an operator (especially specialist

plant), regular maintenance & troubleshooting of the plant

• Hirer usually insures the plant and ensures regular checks to fulfil

statutory codes and safety requirements

Hire vs. Purchase of site plant

Advantages of purchase:

• Plant are always within control of contractor, thus making

deployment plans more accurate, realistic and productive

• Depending on the lifespan and cycle of each individual plant, cost

to own is usually cheaper as compared to hiring, bearing in mind that some plants can be recycled via simple and affordable modifications at the peak of their lifespan, not forgetting the reimbursements from scrap-yards as well

• Plant could be inter-deployed amongst the contractor’s different

sites, depending on severity of need. This practice is common in many companies due to its enormous savings initiative that far

• utweighs the additional burden of deployment and

accommodations within project schedules.

Hire vs. Purchase of site plant

Site plant and equipment are generally categorised into 4 main areas

• f function, namely:

1. Transportation-related (i.e. of people and materials): e.g. Hoists, Lorries, Barges, Conveyor-Belt Systems, Suspended Working Platforms, …etc. 2. Earth-related: e.g. Excavators, Scrappers, Compactors, Dredgers, Piling Machines/Hammers… etc. 3. Lifting: e.g. All types of Cranes. 4. Material handling: e.g. Concrete mixers, ‘Elephant’ Concrete Pumps…etc.

Categorising construction plant

Transportation-related plant

• This concerns the handling of materials and components
• Most construction materials used in the erection of buildings are

handled several times during the course of construction

• Transportation plant generally deliver along a horizontal axis (e.g.

common lorries and trucks) whereas for vertical movements, plant such as hoists and elevating platforms were as covered in a previous unit

Transportation-related plant

These are vehicles designed for the transportation of materials that were previously carried out by (e.g.) wheelbarrows, such as excavated spoil, hardcore and

• concrete. It is faster and more economical than hand-

barrowing and consists of a shallow tipping hopper or skip mounted on a wheeled chassis

Dumpers:

• It is essentially a mobile chassis on the front of which is a

vertical frame or mast on which a pair of projecting tines (or ‘forks’) may be raised and lowered.

• It is basically used for handling unit or packaged loads such as

crates and pellets of construction materials.

Forklift trucks:

• They are capable of moving
• n both land and water and

are suitable for coastal and waterways projects such as reclamations, bank walls construction…etc.

• These heavy-looking machines

actually float on water as the bottom travelling chassis including the crawler is hollow

• These vehicles drive in a

similar fashion when travelling

• n land

Amphibious machines:

• A ready-mixed concrete truck

discharging its contents. Most mixing-drums are of 6m3

• The contractor will place orders
• nly upon confirmation of the

casting schedule right up to the hour, so as not to risk premature setting prior to discharge on site

• Note that once loaded and

mixed, the concrete will have to be disposed from the drum within stipulated timings

Ready-mixed concrete trucks:

• This heading covers a wide

variety, ranging from light- weight pick-up trucks to heavy-tonnage lorries and trailers

• Some are equipped with

accessories such as hydraulic cranes and dock-levellers

• For the transportation of both

people, materials and peripheral site components, they come in all sizes and variants.

General-purpose transport:

Earth-related plant

Some work factors to be considered in selecting earth-related plant:

• The nature of the works to be performed (e.g. excavation,

piling, compacting, grouting…etc.)

• The type of soil to be encountered
• The distances that the excavated/displaced spoil must be

carried to transport

• The condition and gradients of the site

Earth-related plant

• These machines consist of a

scraper bowl which is lowered to cut and collect soil where over- site excavation, surface stripping and levelling operations are required involving large volume of earth

• When the scraper bowl is full, the

apron at the cutting edge is closed to retain the earth and the bowl is raised for travelling to the disposal area

• They commonly come in towed,

two-axle and three-axle formats

Scrapers:

Scrapers:

http://www.youtube.com/watch?v=p5yhtxRmsUU

• Cut, mix and pulverize native in-place soils with additives or

aggregates to modify and stabilize the soil

• Using a rotary cutter, they blend additives with base or subgrade

material to a specified depth

• They can also be used to size the stabilising material to specific

particle sizes or aerate the soil

• They are acknowledged as the enhanced version of the common

scrapers

http://www.youtube.com/watch?v=Y4dUQHQ-RpQ

Soil stabilisers:

• Used for all modern road

construction around the world, these pavers are extremely efficient in the fast and even distribution of asphalt in new construction or resurfacing

• Wheeled pavers provide rapid

mobility and a smooth ride. Tracked pavers favour sandy, loose soil, sub-base or base materials that do not permit good traction by wheeled pavers.

Asphalt pavers

http://www.youtube.com/watch?v=yCzZilHtVM0 http://www.youtube.com/watch?v=5SdLPSPCJUc

Asphalt pavers

Hydraulic backhoe excavators:

Sometimes known as a ‘backhoe loader’, the hydraulic backhoe excavator is designed for a number

• f

different excavating

• perations

by changing the booms and buckets.

Hydraulic backhoe excavators:

Hydraulic backhoe excavators:

Hydraulic backhoe excavators:

http://www.youtube.com/watch?v=OmCdVfHznn0 http://www.youtube.com/watch?v=X_dGEWSwM2E

Hydraulic backhoe excavators:

It is used for excavating against a face or bank, consisting of an

• pen-top bucket or dipper fixed to an arm or dipper stick that

slides and pivots on the jib of the crane. It is suitable for excavating all clay, chalk and friable materials and for handling rock and stone. However, it is not suitable for surface excavation for which a skimmer is used

Face shovel:

Face shovel

http://www.youtube.com/watch?v=eFN0Q5Jmof8

It is similar to the face shovel except that the dipper stick pivots on the end of the jib with the dipper

• r bucket working towards

the chassis and is emptied by swinging away from the chassis to invert the bucket. It is mainly used to excavate trenches and occasionally used for the excavation of

• pen areas such as small

basements.

Backhoe/ Backactor:

https://www.youtube.com/watch?v=FAicE_ACRVo https://www.youtube.com/watch?v=h2-H800kGlU

Backhoe/ Backactor:

It consists of two hinged half-buckets or jaws pivoted to a frame which is suspended by cable from a long jib of an excavator. It works from the side of the excavation at normal ground level and is used for excavating large

• pen

excavations such as basements when the depth is beyond the limit of the boom of a backactor.

Draglines:

https://www.youtube.com/watch?v=K-5njUjswq4

Draglines:

They rely on their dead weight to compact the soil via smooth wheeled rollers. They are used in road works and have limited applications in earthworks.

Static weight compactors:

Vibrating rollers:

Their principle is similar to the static weight compactors’, but are technically more efficient as the induced vibration assists in further

• compaction. Hand-

propelled vibrating rollers are efficient as well. They are suitable for compacting granular fill such as graded sand, gravel and hardcore. However, they are not suitable for cohesive soils.

http://www.youtube.com/watch?v=4CorwF_6Ab8

Vibrating rollers:

The bulldozer consists

• f

a rectangular steel blade with renewable cutting edge set at right-angles or about 30 degrees to the direction of travel and attached by steel arms to the side frames of a crawler tractor. It may be used for levelling or skimming surface soil or for moving loose debris in a forward motion

Bulldozers and angle-dozers:

http://www.youtube.com/watch?v=Q1gCqhNF4Ss

Both chassis and power plant are based essentially on the excavator model. Equipped with hanging leaders that guide the pile and the hammer during driving.

https://www.youtube.com/watch?v=QUZAoUu44 Xs

Pile driving rigs

Drilling rig

Equipped with turntable through which the drilling rod or kelly bar passes for drilling.

Augur rotary drilling rig

Lifting plant

As with its transportation counterpart, this concerns the handling of materials and components. Most building materials used in the erection of buildings are handled several times during the course of

• construction. The plant used for lifting, primarily deliver along a

vertical axis.

Lifting plant

Mobile cranes: These may either be self- propelled or truck-mounted. They are suitable where

• n-site

mobility is

• f

a primary requirement or where duration of the job is short. It is widely used for the erection

• f

low-rise buildings where a long reach is not essential and the machine be positioned near to the building, and for the erection of low framed structures requiring the crane to traverse between columns of the structures.

Common specifications and components: A typical static tower crane has the following specifications:

• Typical unsupported height – 80 metres
• The crane can have a total height much greater if it is tied and

secured to a permanent structure (e.g. a building), or as a building under construction rises upwards to support the crane (climbing cranes).

• Typical reach – 70 metres
• Typical lifting power – 18 metric

tons

• Counterweights – 16.3 metric tons

(e.g.) If the maximum load that the crane can lift is 18 metric tons, it cannot lift that much weight if the load is positioned at the end of the jib.

Stationary Cranes:

Climbing tower crane

https://www.youtube.com/watch?v=JT4yX3y 3dvw

Floor climbing tower crane

Material handling plant

The advantages of mechanical mixing

• ver hand mixing, except for very small

quantities, are greater economy, reduce in loss of materials and more accurate gauging of the water content. Concrete Mixers are made in various types and sizes and are broadly classified as either ‘batch’ or ‘continuous’ mixers. These portable site concrete mixers produce minimal quantity in single or continuous batches via manual material feeding, thus consistency of mix proportions may be questionable.

Concrete mixers:

Designed specially for the transportation of concrete from a discharge point to casting locations. When ordering ready-mixed concrete for pump operations, the supplier has to be informed that a ‘pump-grade’ supply is to be delivered, (i.e.) a grade that is more workable by flow. Concrete pumps come in mainly two variants: trailer-mounted or truck- mounted with a discharge boom.

Concrete pumps:

Concrete pumps:

http://www.youtube.com/wat ch?v=3gII2XOfA8s&feature =related https://www.youtube.com/wa tch?v=i9lWUicgySQ

Construction site with concrete pump truck

There are numerous types of plant and equipment available in the industry today, with a good selection of manufacturers and models from which to choose and meet most modern construction

• requirements. While customisation of equipment is fairly common in a

bid to save costs on upgrades and to boost mechanical productivity, modern site equipment is being developed by global manufacturers with a steep inclination towards Multi-tasking capability: With every piece of machinery having the capability to perform its primary role(s) and enhanced secondary functions with convenient add-on

• accessories. A multi-purpose mobile backhoe excavator is a classic

example of such machines.

Modern plant requirements/ Conclusions