Stay Cable Inspection
Ensure the safety, durability, and load-bearing performance of your cable-stayed structures with DYWIDAG’s stay cable inspection services. Over time, aging, environmental exposure, and repeated load cycles can lead to hidden deterioration. DYWIDAG provides certified, non-destructive inspection solutions that detect both visible and internal damage, helping asset owners manage risk, maintain compliance, and extend service life.
Why stay cable inspection is essential
Stay cables are critical load-bearing elements that directly influence the safety and long-term performance of bridges, stadiums, and other cable-stayed structures. Through out their service life, cables are exposed to environmental exposure, and repeated load cycles, leading to progressive and often hidden deterioration:
Wire or strand breaks caused by corrosion or mechanical damage
Loss of metallic cross-sectional area, reducing load-bearing capacity
Fatigue damage resulting from cyclic loading
Grouting detachment in grouted systems, compromising corrosion protection
Without targeted inspection, these defects can remain undetected. Undiagnosed, cable deterioration may result in reduced load-bearing capacity, unplanned traffic restrictions, accelerated intervention measures, and increased lifecycle costs.
Regular, professional stay cable inspection enables asset owners and operators with a reliable basis for assessing structural condition, quantifying risk, and prioritising maintenance or intervention measures .
Surface defects in stay cable systems
Different cable systems exhibit distinct surface degradation mechanisms over time. While surface defects may initially appear limited in scope, they often represent early indicators of compromised corrosion protection and if not addressed, can accelerate internal deterioration. System-specific inspection approaches are therefore essential.
Surface defects in full locked cables (FLC)
In full locked cable systems, aging of the outer mechanical or corrosion protection layer can lead to paint detachment, cable bleeding, and corrosion of outer wires. These defects not only affect appearance but may also indicate reduced effectiveness of the protective system, increasing the risk of moisture ingress and progressive corrosion. While often first observed as surface damage, these defects can progress into structural deterioration if not identified and addressed at an early stage.
Surface defects in PE-encased cable systems (PWS & PSS)
Polyethylene-encased systems such as parallel wire systems (PWS) and parallel strand systems (PSS) are primarily affected by UV-induced aging of the PE sheath. This can result in cracking or embrittlement of the polyethylene and loosening of helical fillets, often caused by external mechanical damage. In some cases, excessive grout pressure during installation can introduce initial micro-damage to the PE casing. Combined with long-term UV exposure, this can significantly accelerate surface degradation and compromise the protective function of the sheath.
Early identification of surface defects allows targeted maintenance measures, such as stay cable cleaning or sheath repair, to be implemented before deterioration progresses to internal structural damage.
Why choose DYWIDAG for stay cable inspection?
Decades of cable expertise
With decades of hands-on experience across all cable types, DYWIDAG delivers reliable, efficient, and tailored inspection solutions for complex structural challenges worldwide.
Smart technology meets skilled access
We combine advanced inspection technologies — robotics, magneto-inductive testing, and force measurement - with certified rope access for safe, flexible, and non-invasive inspections.
Deep structural insight
Our non-destructive magneto-inductive inspections detect hidden wire breaks and internal corrosion, enabling early intervention and informed maintenance planning.
From insight to action
Beyond inspection, DYWIDAG identifies suitable repair strategies and delivers complete strengthening and maintenance solutions when required.
From inspection to intervention
Stay cable inspection provides a critical input for condition-based asset management. When defects or early-stage deterioration are identified, DYWIDAG supports asset owners with targeted follow-on measures designed to mitigate risk and maintain structural performance.
Based on inspection findings, DYWIDAG delivers coordinated solutions including stay cable cleaning to remove surface contaminants, stay cable sheath repair to address cracking, UV damage, or mechanical defects, stay cable protection systems to enhance long-term corrosion and UV resistance, and damper replacement or retrofit to reduce vibration-induced fatigue.
By integrating inspection, assessment, and intervention within a single technical framework, DYWIDAG enables faster decision-making, reduced interface risk, and maintenance strategies that are directly aligned with measured cable condition and lifecycle objectives.
Proactively manage risk, ensure compliance, and extend the service life of your assets with DYWIDAG’s stay cable inspection services.
Comprehensive stay cable inspection by DYWIDAG
DYWIDAG delivers a holistic cable inspection approach that addresses both surface-level and internal structural conditions.
Certified visual inspections with rope access
Visual inspections performed by certified bridge inspectors in accordance with DIN 1076
Main inspections typically carried out every six years
Close-up inspections executed using rope access by FISAT Level 3 certified technicians
No scaffolding required, ensuring faster execution and minimal traffic disruption
Robotic cable inspection with panoramic imaging
For long free cable lengths, DYWIDAG deploys robotic inspection systems that:
Capture high-resolution 360° panoramic images
Enable consistent documentation of the entire cable surface
Support precise comparison across inspection cycles
To ensure reliable and repeatable results, imaging is performed in a controlled environment shielded from direct sunlight and supported by artificial lighting. This allows accurate assessment of defect progression over time.
AI-assisted data interpretation supports early identification of potential risks, while certified inspectors validate all findings to ensure dependable condition assessments
Magneto-inductive inspection for hidden damage
Magneto-inductive testing is a powerful complement to visual inspection and is essential for detecting internal stay cable defects that are not visible from the surface.
This non-destructive testing method magnetizes the entire metallic cross-section of the cable, including the inner core; using permanent magnets, fully compliant with DIN EN 12927. Complete magnetic saturation is essential, as defects cannot be reliably detected without it.
Magneto-inductive inspection reliably detects both internal and external wire breaks, as well as loss of metallic cross-section across the entire cable. These results provide a solid basis for evaluating structural safety, traffic safety, and long-term durability, including an informed estimate of any loss in load-bearing capacity.
Advanced defect localization
Using a combination of induction coils and Hall sensors, the Mageneto-inductive inspection system enables precise three-dimensional localization of defects within the cable. Measurements are repeatable, interference-free, and directly comparable across inspection cycles, ensuring reliable condition assessment over time.
DYWIDAG offers inspection devices for cables up to 315 mm in diameter, suitable for full locked cables, spiral strands, strand ropes, and parallel wire or parallel strand systems. Importantly, inspections are carried out without dismantling HDPE sheathing or existing corrosion protection systems, enabling efficient, non-invasive assessment even in hard-to-reach areas.
Certifications & compliance
Standards-compliant testing
Full magnetization of the entire metallic cross-section in accordance with DIN EN 12927, using CE-conform inspection systems.
Regulatory inspection coverage
Supports DIN 1076 requirements, including mandatory main inspections (Hauptprüfung, HP) every six years.
Mandatory testing for critical systems
Fully compliant with ZTV-ING Part 4.4, where magneto-inductive testing is required for fully locked ropes and strand bundle systems.
Certified specialist execution
Inspections carried out by FISAT-certified rope access technicians, with FISAT being a member of the European Committee for Rope Access (ECRA).
Related Services
Stay cable sheath repair
Essential stay cable sheath and cover repair, and replacement services to keep your cable-stayed structures safe and performing at their best.
Stay Cable Protection
Providing in-depth technical advice and advanced repair technologies customized to your project's unique conditions.
Stay cable detensioning and exchange
Controlled release and reinstallation of stay cables, ensuring structural stability and safety at every stage.
Cable cleaning and surface maintenance
Removal of surface contaminants, to prevent long-term degradation of the sheathing and anchor zones.
Damper replacement and retrofit
DYWIDAG offers inspection, replacement, and retrofit services for stay cable dampers.
Renforcement
Prévenir les dommages structurels et le vieillissement grâce à une protection spécialisée contre la corrosion, les rayons UV et les risques d'incendie.
Cableskin
Protection à long terme contre les UV et la corrosion avec une perturbation minimale de la circulation.
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