Asset management

Table of Contents

3.6 VMS – Failure of Structural Support

Field masts, gantries and poles offer the structural support systems for VMS. Failure can cause the VMS to become unstable and vibrate or fall from a height. Prominent causes of structural failure include:

  • failure of foundation
  • load on structure increased or modifications to the structure (such as additional holes) reducing the structural capacity
  • manufacturing defects
  • structure commissioned incorrectly
  • failure under high winds or extreme weather conditions.

Instability and vibration of the VMS can cause damage to internal components and connectors. VMS falling down can also cause crashes. Structural failure was rated as critical (2 out of 3 levels).

Deterioration of structural components above ground is readily visible and can be easily monitored and rectified as part of the current scheduled inspection tasks. The key issue is foundation failure, which is not easily detectable. Recommended mitigation measures include ensuring that installations are prepared correctly and that random foundation condition assessments are done systematically to identify potential failure trends.

An example RCM process applied to VMS where there has been failure of structural support is presented in Case Study 7.

Case Study 7: RCM Process where there has been a Failure of Structural Support
ItemDescription
Component
  • Field masts, gantries and poles (support system of VMS)
Function
  • To support VMS displays and equipment
Functional failure
  • Failure of structural support system
Most prominent failure mode
  • Failure of foundation
  • Load on structure increased or modifications of the structure (such as additional holes) reduce structural capacity
  • Manufacturing defects
  • Structure commissioned incorrectly
  • Failure under high winds or extreme weather conditions
Failure effect
  • VMS becomes unstable
  • VMS falls from height due to failed support system, causing injury or damaging property
Determine criticalityFailure consequence
  • Severe to most severe
Likelihood
  • Not likely
Criticality
  • Critical (yellow)
List possible task (if applicable)On-condition maintenance task
  • Inspection and restoration when required
Change in commissioning
  • Improved inspection of foundations during commissioning and handover
  • Ensure that additional loads are within the load capacity of structures
Fault finding (testing)
  • Consider non-destructive testing techniques
  • Testing of buried components (high-risk components for corrosion)
Equipment redesign
  • Review and re-engineer problematic and frequently failing components
Call-out maintenance
  • Conduct call-out repairs as currently practised
Remarks
  • Deterioration of structural components above ground is readily visible and can be easily monitored and rectified as part of the current scheduled inspection tasks
  • Key issue is foundation failure, which may not be easily detectable. Mitigation measures include ensuring that the installation is done properly and that random foundation condition assessments are done systematically to identify potential failure trends in foundations.