Cost of Service Life Optimization Part 1: de Sitter’s ‘Law of Fives’

Our own Innovation Engineer, Nick Heim, P.E., was featured in the Engineering Management Institute. This is part one of the series.

He takes a deeper dive into the importance of periodic inspection of structures to enhance public safety and reduce future costs through service life optimization. It introduces de Sitter’s "Law of Fives," which outlines four phases in the lifecycle of concrete structures and emphasizes the significant return on investment from proper initial design and maintenance.

Key Highlights in the Article:

Periodic Inspection for Public Safety:

• Regular inspections help identify issues in structures that may deteriorate due to environmental factors.
• Addressing these issues often requires significant funding.

Service Life Optimization:

• Asset owners seek ways to reduce future costs after reviewing inspection results.
• Service life optimization is presented as a solution.

de Sitter’s ‘Law of Fives’:

• Introduced by Wolter Reinold de Sitter about 40 years ago.
• Proposes four phases in the lifecycle of concrete structures:
  • Phase A: Good Practice (initial design, construction, quality control)
  • Phase B: Maintenance (general maintenance, periodic inspection)
  • Phase C: Repair and Maintenance (isolated concrete removal and replacement)
  • Phase D: Renovation (widespread concrete removal and replacement)

Financial Implications of de Sitter’s Theory:

• The theory states: “One dollar spent in Phase A equals $5 in Phase B equals $25 in Phase C equals $125 in Phase D.”
• Implies a fivefold increase in spending from phase to phase.
• Emphasizes the importance of investing wisely during initial design and maintenance for significant returns.

Focus on Phases A and B:

• de Sitter highlights that attention should be focused on Phases A and B for optimal results.
• Proper initial design and general maintenance are crucial for long-term cost savings.

Deterioration Mechanism:

• Corrosion of reinforced steel is a primary cause of concrete structure deterioration.
• Increased interest in concrete durability due to frequent damage occurrences.

Correlation Between Cost and Corrosion:

• Cost is correlated to corrosion over time.
• Corrosion contributes significantly to the deterioration of concrete structures.

Read the full article to dive deeper into each of these topics.