In the world of construction, post-tensioning (PT) is a specialist domain. When disputes arise—whether due to structural failure, water ingress, corrosion, improper installation, or unexpected movement—the root cause is often complex and technical. This is where the role of an expert witness becomes critical.

Over the years, I’ve been asked to provide expert opinions on PT-related claims across Asia, often involving high-stakes legal or insurance proceedings.
Here’s a look at what the role of an expert witness really involves in post-tensioning disputes—and what clients should expect when engaging one.

1. What Is an Expert Witness in Construction?

An expert witness is a recognized specialist with the qualifications and experience to offer a professional opinion on technical matters in dispute.
In construction, and especially in post-tensioning, these opinions are used to support or challenge claims relating to design, workmanship, materials, or safety.

An expert may be appointed by one party (plaintiff or defendant), or jointly by both, depending on the nature of the dispute and the legal jurisdiction involved.

2. Why PT Disputes Require Specialized Expertise

Post-tensioning systems—whether internal, external, bonded, or unbonded—are highly engineered and often hidden from view once constructed.
That makes diagnosis particularly challenging. Common PT-related disputes include:

• Tendon failure or slippage
• Corrosion due to poor grouting or sealing
• Cracking, deflection, or abnormal movements
• Non-conformity with specifications or standards
• Delays or cost overruns related to specialist work
• Responsibility attribution between designer, contractor, and supplier

Because these disputes hinge on understanding detailed construction methods, system performance, and failure modes,
generalist engineers or legal experts often lack the insight needed. That’s where the expert witness comes in.

3. Responsibilities of the Expert Witness in PT Disputes

The role of the expert witness includes, but is not limited to:

a. Review of Project Documentation

• Drawings, specifications, calculations, and approvals
• Grouting records, stressing logs, quality control forms
• Correspondence, change orders, method statements

b. Site Inspections and Assessments

• Visual and borescope inspections
• Use of tapping, coring, or camera tools
• Assessment of tendons, ducts, and anchorages

c. Causation Analysis

Identifying whether failure was due to design, workmanship, materials, or environment, and comparing actual conditions to design intent and standards (e.g., fib, EN, ACI).

d. Expert Report Preparation

Producing a clear, independent technical report that can support litigation, arbitration, or insurance negotiations.

e. Court or Arbitration Testimony

Presenting findings in formal proceedings and explaining complex technical concepts to non-specialists.

4. Qualities to Look for in a PT Expert Witness

• Extensive practical experience with PT design, installation, and troubleshooting
• Knowledge of multiple systems: Freyssinet, VSL, DSI, BBR, CCL, etc.
• Familiarity with both new construction and failure investigations
• Clear communication skills, both written and oral
• A reputation for objectivity and professional integrity

5. When to Engage an Expert

The earlier an expert is engaged, the more value they can offer—often helping to de-escalate technical disagreements before they become formal disputes.

• Clarify facts early during mediation or negotiation
• Support insurance claims with expert evidence
• Assist legal teams in building a technically sound argument

6. Real-World Example

In one case, a dispute arose over tendon corrosion discovered several years after bridge completion.
The contractor argued poor maintenance; the client blamed faulty grouting.
After reviewing as-built records, vent cropping reports, and site photos, I found that grout vent caps were never installed—allowing moisture ingress.
My expert opinion helped the parties reach a settlement before entering arbitration.

Final Thoughts

Post-tensioning disputes are highly technical. A qualified expert witness provides independent, experience-based insight that helps clarify complex situations and support fair resolutions.

At MONBALLIU Consulting, I offer independent expert witness services based on 40+ years of hands-on PT experience across Asia, Europe, and the Middle East.
Whether you’re seeking a second opinion, preparing a claim, or resolving a dispute—I’m ready to help.