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Readybuild: Pre-fabricated rebars ready-to-fix at site leading to faster construction

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By
Sourav Dutta
Manager-Civil

Common Hazards/issues normally countered at all construction sites:

Human error in rebar fabrication (manual).
Fig 1 Incorrect bend
Fig 1 : Incorrect bend

Compromise with safety and quality.

Fig 2 Safety and Quality issues upon using rebar cutter
Fig 2 : Safety and Quality issues upon using rebar cutter

Procurement schedule delays affecting site progress, and thereby delaying project completion.

Inventory management. Capital locked in inventory.
Fig 3 Lack of space at site affects storage procurement
Fig 3 : Lack of space at site affects storage/procurement

Rebar pilferage.

Scrap generation and its disposal. Also leading to revenue loss.
Fig 4 Scrap generation at site
Fig 4 : Scrap generation at site

Rebar reconciliation: A challenge to keep wastage within limit.

Space/electric supply availability for bending machine setup.
Fig 5 Bending machine
Fig 5 : Bending machine

Scarcity of skilled masons/labors now-a-days for rebar fabrication. Moreover, their availability during festive season is always an issue.

India continues to use rebar in straight form, other countries have moved to fabricated/Cut & Bend steel.

other countries have moved to fabricated/Cut & Bend steel.

Advantages of Cut and Bend Steel

  • Cost Savings.
  • Procurement against exact requirement/orders as per provided Bar bending schedule (BBS).
  • Lesser Space required for inventory.
  • Timely Delivery and Reliability.
  • Reduction in working capital in the project. Improves margin.
  • Improved quality and any shape can be accurately fabricated.
  • Helps in account reconciliation.
  • Direct Usage – practically no space blockage.
  • Labor required only for binding / placing / fixing.
  • Faster Construction.
  • No scrap/offcut generation/pilferage.

Quality improvement on using Cut and Bend Rebar
Slope not exceeding 1 (Horizontal) : 6 (Vertical) as per IS456:2000 in column rebar at splice location

Fig 6 (s)- Column rebars
Fig 6 (s) : Column rebars

Fig 8 (s) Stirrup manufacturing Wrong & correct practise
Fig 7 (s) : Proper mandrel dia used for bending rebar

Fig 8 (s) Stirrup manufacturing Wrong & correct practise1
 Fig 8 (s) : Stirrup manufacturing: Wrong & correct practise

A cost comparison for rebar cut & bent at site vs prefabricated rebar is being given for reference:
Cut & bend cost comparison for rebar

Rebar quantity / month = consider average 100 T/month

At site:

Activity detail Labour cost (L) Material cost (M) Plant cost (P) Overhead cost (O) Total Cost (L+M+P+O) Consideration
Basic material price 35000* 35000
BBS making charges (staff) 100 100 1 jr. staff with salary=Rs 10000 pm
Supervision charges (staff) 180 180 1 staff with salary=Rs 18000 pm
Loading & unloading of rebar from stockyard to fabrication yard 50 50
Cut & bend labor charges 2500 2500 Consider cut-bend-tying=Rs4000/T, tying component= Rs 1500/T
Cutting machine hire charges 100 100 Consider hire charge= Rs10000/month
Bending machine hire charges 100 100
Electricity charges 20 20
Inventory charges 350 350 1% of rebar cost for 30 days
Lead & lift of rebar from fabrication yard to construction site 50 50
Scrap @5% material cost 1750 1750
Collection of scraps and disposal 25 25 Consider Rs 500/T
Savings on selling scrap @ Rs26/Kg -1300 -1300
Total cost per MT at site (Rs) = 38925

 

For Cut & Bend (Prefabricated) rebars:

Activity detail Labour cost (L) Material cost (M) Plant cost (P) Overhead cost (O) Total Cost (L+M+P+O) Consideration
Basic material price   35000*     35000  
Average deviation for Cut & Bend, delivered at construction site 3000 3000 Varies about Rs 3000-3500/T depending upon certain factors
Estimated Cut & bend price per MT (Rs) = 38000  

Profit of site on using Cut & Bend (%) = (3925-3000)/3925 = 23.6%
*: Indicative basic material price considered for comparison.

We at engineeringcivil.com are thankful to Er. Sourav Dutta for submitting this paper to us. We hope this paper will be helpful for the whole construction industry in general.

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