David Mitchell 5D bim today’s workflow for cost certainty
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This document discusses how construction cost certainty can be achieved through 5D BIM (Building Information Modeling). It notes that traditional construction costs often exceed estimates by 28% on average. 5D BIM involves a QS (Quantity Surveyor) mapping item quantities in a BIM model to generate cost estimates. When used for an entire project rather than just structural steel, 5D BIM can reduce cost overruns to just 2% compared to 27% for traditional methods. The document outlines skills needed for a 5D QS and how 5D BIM was used to generate trade package quantities for tender on the Sunshine Coast University Hospital project.
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David Mitchell 5D bim today’s workflow for cost certainty
- 1. 5D BIM: Today’s Workflow for Cost Certainty 3rd Annual BIM Summit Sydney 26th August 2013
- 2. Discussion How Uncertain are Construction Costs? What Level of Certainty can be Achieved? How do I Create Savings? What Skills does a 5D QS need? 5D BIM Execution Plan Deliverables SCUH
- 3. How Uncertain are Construction Costs?
- 4. How Uncertain is the Market? Research by Evans & Peck, University of Melbourne (2009) • Victorian alliance projects • Average cost increases: • Business Case v TOC +35 - 45% • TOC v Final Cost +5 – 10% Research by Flyvbjerg et al (2003) • 258 projects in 20 nations • 90% of projects had cost overruns • Average cost increase +28% Source: “In Pursuit of Additional Value” - Evans & Peck + The University of Melbourne, Oct 2009 : http://maxwellsci.com/print/rjaset/v5-2621-2629.pdf
- 5. Source: Mitchell Brandtman MB Brisbane - Financier Watching Brief 1,100 Private Sector Financed Projects: • Procurement Type: • 64% Lump Sum • 17% Owner Builder • Project Type: • 54% Residential • 16% Industrial • Cost Overruns: • Range -13% to +321% • 1 in 4 Projects > +5% -25.0 0.0 25.0 50.0 75.0 100.0
- 6. What Level of Cost Certainty can be Achieved?
- 7. Structural Steel Shop DrawingsStructural Steel Fabrication & Erection
- 8. Final Costs & Time – Structural Steel v Entire Contract % Change Entire Contract: Extensions of Time (38 No) + 57% Variations (321 Claims) + 27% Structural Steel Component (15%): Extensions of Time (zero) + 0% Variations (5 Claims) + 2% Source: Mitchell Brandtman
- 9. How do I Create Savings?
- 10. Head Contractors v Sub Contractors 83.0% Subcontract 14.0% Head Contractor - Preliminaries 1.2% Head Contractor - Overheads 1.8% Head Contractor - Profit 15% Profit 68% Labour & Materials Source: Mitchell Brandtman
- 11. Who Owns the Savings? Source: Mitchell Brandtman Designer Owner D&C Contractor D-B-B Contractor D&C Subcontor D-B-B Subcontor LOD 100 CONCEPT DESIGN Functional efficiency Mass and form optimisation LOD 200 SCHEMATIC DESIGN Design workflow efficiency Alternative methods & systems LOD 300 DEVELOPED DESIGN Design workflow efficiency Alternative materials & products Accurate contract documents LOD 300 "FOR CONSTRUCTION" Accurate "for construction" documents VDC - Construction scheduling, operations & LOD 400 CONSTRUCTION Administrative workflow efficiency Site efficiency Risk reduction LOD 500 OPERATION Administrative workflow efficiency Materials & equipment optimisation PHASE & SAVING TYPE SAVING OWNERSHIP headcontractlet subcontractlet White No ownership Red Low ownership Orange Medium ownership Yellow High ownership Green Complete ownership
- 12. Design & Bid Pre-Construction (1 month) Construction Arch LOD 300 Struc LOD 300 QS Model Map MEP LOD 200 4D Info 5D Info MEP LOD 300 Steel LOD 400 Prefab LOD 400 4D Time 5D Costs Designers - Coordination & Clash Builder - Coordination, Clash, Activities & Rates StartConstruction For Tender Federated Model For Construction Federated Model Plan to Build & Nominated SC SelectPreferredBid
- 13. Lean Construction & BIM • Waiting – for materials or specifications • Over Production – producing more than is required • Rework – any work that has to be rectified • Inventory – too much or too little inventory • Transportation – double handling and moving equipment or materials Source: "Recommended Practices for the Application of LEAN Construction Methods to Building New Australian LNG Capacity" by Engineers Australia (Western Australia Division)
- 14. What Skills does a 5D QS need?
- 16. Improve Information – No need for QSID or Codes Add Parameters
- 17. Mapping – BQ Level of Detail
- 18. Pushing Information & Round Tripping
- 19. Negotiations & Price Transparency • Revised • New • Deleted
- 20. Revisioning • Revised • New • Deleted
- 21. 5D BIM Execution Plan
- 23. Sunshine Coast University Hospital
- 24. Deliverables - Revisioning • Revised • New • Deleted
- 25. Deliverables – Visual Subcontract Qtys for Tender
- 26. Trade Package Quantities - 3D v 2D 94% 3D 6% 2D Source: Mitchell Brandtman 3D v 2D by Cost 61% 3D 39% 2D 3D v 2D by No of Items
- 27. Final Words 5D creates better buildings by: • Enabling early cost decisions • Targeting money in a transparent way 5D QS creates cost certainty by applying: • Wisdom – know how • Intelligence – templates, maps & data • Technology – weekly revisioning
- 28. Download presentations and articles from: www.mitbrand.com/info/publications Thank You