Resource Management

Dr Adewale Abimbola, FHEA, GMICE.

www.edulibrary.co.uk

Aim

and Objectives

Aim: Resource Management�Objectives: At the end of the lesson, the students should be able to:

• Describe the management strategies for dealing with materials on-site.

Learning Outcome and Assessment Criteria

• P9 Describe the management strategies for dealing with materials on-site.

Intro. Quiz

List the different types of waste generated on a typical construction site.

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Construction Waste

• Common construction key waste products?
• Building Materials

- Insulation

- Plasterboard

- Timber general

- Blocks

- Bricks

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• Packaging:

- Plastic packaging

- Cardboard

- Timber pallets & packaging

• Other:

- Miscellaneous (e.g. canteen and office)

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The True Cost of Construction Waste

E.g. For 8 cubic yard skip:

• Skip disposal cost £XX
• Labour to fill skip £XXX
• Cost of materials put in skip £XXXX
• TOTAL TRUE COST £XXXX

Nearly 15x the disposal cost

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True cost of waste is 10-20 times the disposal cost.

(Source: AMEC)

Construction Waste

Common causes:

• Offcuts
• Unsuitable storage
• Packaging
• Over-ordering
• Project management and programme
• Rework

Natural Waste:

• Inevitable waste, including leftovers from cutting bricks for bonding, residue in containers, small quantities from batch production, cutting elements for service pipes, etc.

Direct Waste:

• Preventable waste through effective management and planning.
• Examples: Material losses on-site (e.g. material loss due to damage during transportation and construction, stolen materials, excess orders requiring removal, or materials forgotten and stacked out of sight necessitating reordering, etc.).

Construction Site Waste

Figure 1. Categorising materials delivered to construction sites (March, 2009).

Indirect Waste:

• Discrepancy between estimated and actual costs that cannot be transferred to the client.
• Examples:
• Builders' errors (e.g. incorrect setting out of structures, uneven surfaces, etc.).
• Return visits to finish incomplete work.

Construction Site Waste

Figure 1. Categorising materials delivered to construction sites (March, 2009).

Construction Site Waste – Further Sub-division

i. Inactive Waste:

• Materials causing no significant reactions in landfills. Inert construction & demolition waste.
• Examples: Soils, rocks, concrete, ceramics, masonry, brick, and minerals.

ii. Active Waste:

• Materials undergoing change in landfills. Biodegradable waste.
• Examples: Acids, alkaline solutions, pesticides, wood preservatives, oils, asbestos, timber, plastics, bitumen, and batteries.
• Attracts a higher landfill tax than inactive waste.

Figure 2. Categories of site waste.

Construction Site Waste – Further Sub-division

iii. Special (Hazardous) Wastes:

• Deemed dangerous to life.
• Some overlap with active waste.
• Materials: Toxic, very toxic, corrosive, reactive, explosive, carcinogenic, or flammable.
• Examples: Acid and alkaline solutions, waste oils and sludges, wood preservatives.

Figure 2. Categories of site waste.

Group-assessment Task

Inadequate management of construction sites can lead to significant pollution, impacting health and the environment. How will you address the following pollution sources:

• Demolition products such as wood, metal and rubble, soil from earthworking, bricks, blocks and tiles, and mortar and cement.
• Construction plants and equipment.

Strategies for Effective Construction Material Management

• Kitting: Tailor packaging to create customized kits with precisely the materials required for specific sections of a construction project, enhancing efficiency and reducing waste.
• Site Construction Management Plan: Within the broader construction management plan, include detailed sections outlining strategies for waste, material, and site management. This ensures a systematic approach to optimizing resource utilization and maintaining an organized construction environment.

Waste Reduction Strategies

Analyse waste production, identify causes, and implement action strategies.

Examples:

• Set waste reduction targets.
• Change transportation and packaging methods.
• Pre-cut materials before site delivery.
• Modify designs.

Site waste management plan (template): Site Waste Management Plan

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Just in Time Deliveries (JIT)

• Originated with Toyota in the 1960s.
• Industrialized prefabrication systems and concrete deliveries follow JIT.
• Challenges in the construction industry to fully go JIT because of external factors like unpredictable weather, long haul, etc.
• JIT benefits: reduced inventory costs, efficient material handling.

(129) Just in Time by Toyota: The Smartest Production System in The World - YouTube

(1) NewArk Hotel construction timelapse: 15 storeys in 48 hours. - YouTube

Inventory Optimisation

• Develop a method for convenient, timely, and incremental material deliveries.
• Prevent work interruptions for material handling.
• Aim for efficient material storage and handling to enhance workflow.

Safety Stock

Z-score MS Excel formula = NORMSINV()

Worked Example 1:

A project manager records the daily use of A4 photocopier paper in a month (Table 1). She has determined that the lead time is 3 days and the service level is 95% (This means the safety stock levels will cover for 95% of all probable requests).

Determine the safety stock; the additional quantity held in inventory to mitigate the risk of a stockout.

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Safety Stock

Safety Stock

Reorder Point

Worked Example 2:

A project manager records the daily use of A4 photocopier paper in a month (Table 1). She has determined that the lead time is 3 days and the service level is 95% (This means the safety stock levels will cover for 95% of all probable requests).

Determine the reorder point to avoid running out of stock.

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Reorder Point

Reorder Point

Minimum and Maximum Order Quantities

Minimum and Maximum Order Quantities

Self-assessment Task 1

A site supervisor monitors the daily consumption of concrete blocks on a construction site over a month (Table 1). After establishing a lead time of 5 days, a service level of 92% and an order frequency of 2 per month, calculate the safety stock, reorder point, minimum order quantity and maximum quantity order to prevent stock shortages.

Self-assessment Task 2

Describe any FOUR management strategies for dealing with materials on-site.

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References/Bibliography

• Canter, M. R. (1993) Resource management for construction. London: Macmillan Press Ltd.
• Hans, R. (2024) What is inventory reorder point in inventory management? Available at: https://www.deskera.com/blog/inventory-reorder-point/ (Accessed: 01 March 2024).
• Henry, R. (2019) Full Guide to Reorder Point (ROP): Definition, Formula & Calculator. Available at: https://www.extensiv.com/blog/reorder-point-safety-stock (Accessed: 01 March 2024).
• March, C. (2009) Operations management for construction. London: Spons Press.
• SITMI Academy (2023) Safety stock | reorder point rop | economic order quantity eoq | min max levels calculation in excel. Available at: https://www.youtube.com/watch?v=pypb4WOOLFI&t=938s (Accessed: 01 March 2024).
• Thieuleux, E. (2022) Safety stock formula & calculation: the 6 best methods. Available at: https://abcsupplychain.com/safety-stock-formula-calculation/#:~:text=To%20get%20the%20safety%20stock,of%20the%20lead%20time%20L.&text=We%20get%20a%20Safety%20Stock,reorder%20point%20of%201345%20pieces. (Accessed: 01 March 2024).