Structures Maintenance Plan
5. Inspections
5.1 Highway structures are subjected to periodic inspections in order to ensure that any defects which may cause an unacceptable safety or serviceability risk or will require substantial maintenance works are identified in a timely manner in order to safeguard the travelling public and the structure itself.
5.2 The main types of inspection and their frequency are as detailed below;
Inspection Type | Hierarchy of Structures Inspected | Description | Frequency |
|---|---|---|---|
Routine Surveillance | Any structure that carries or crosses over an adopted carriageway or footway or is located within the boundaries of an adopted area. | All aspects of the structure that are visible from the adopted carriageway /footway are subjected to a brief visual inspection at the same time as the Highways Inspector is carrying out the Safety Inspection on the adopted area in order to identify any defects that may pose a safety risk to members of the travelling public. Full details of the highway safety inspection process is given in the Council's Highway Safety Inspection Manual. Defects are notified to the Structures Senior Engineer for further investigation | As determined by the hierarchy of the adopted highway on which the structure is located |
Safety Inspection | Any Category | May be undertaken following routine surveillance or after a stakeholder report which indicates the structure is damaged and may be unsafe. The safety inspection should determine the extent of the damage and whether immediate safety precautions or other action should be taken. A special inspection may then follow to monitor the condition and effectiveness of interim measures and to determine what repair or other actions should be undertaken in the longer term | As required |
General Inspection | All Category 1, 2, 3 & 4 structures | A visual inspection of all readily accessible parts of the structure (that can be inspected without the need for special access or traffic management arrangements) and, where relevant to the behaviour or stability of the structure, an inspection of the adjacent earthworks and waterways | Every 2 years |
Principal Inspection | All Category 1 & 2 Structures | A close examination, within touching distance, of all accessible parts of a structure, including, where relevant, underwater parts and adjacent earthworks and waterways, utilising suitable access and/or traffic management as necessary. CCTV, high resolution digital photography/video or drones may be used for areas of difficult or dangerous access. | Every 6 years |
Dive Inspections | Any Category | Specialist inspection of specific structures assessed as being particularly susceptible to scour of the piers. | Every 6 years |
Special Inspections | Any Category | A more specific inspection generally concentrating on the condition of particular parts of a structure. They normally arise due to specific circumstances or following certain events, for example; · When a particular problem is identified during an earlier inspection · On bridges that have to carry an abnormally heavy load · Following a bridge strike Following a flood or high river flow to check for scour or other damage. | As required |
Inspection for Assessment | Any Category | Generally undertaken to provide the information required to undertake a full structural assessment. | As required |
Acceptance Inspection | Any Category | These should be considered when there is a changeover of responsibility for the operation, maintenance and safety of a structure from one party to another. Full details regarding this type of inspection are given in the Technical Approval section of this plan. | As required |
5.3 Where a structure falls within one of the categories requiring a Principal Inspection, it may be deemed appropriate that a General Inspection can provide suitable inspection details due to the ability to view all critical elements in sufficient detail as to not warrant a formal principal inspection. Where this occurs it shall be recorded within the inventory records for the relevant structure.
5.4 When a structure is known or suspected to be subjected to a rapid change in condition, consideration will be given to reducing the interval between inspections (for general and principal inspections) in order to manage the risk of change. The reduced interval shall be such that any significant change in condition or circumstances can be identified and assessed in time for appropriate action to be implemented. The more frequent inspection regime may be limited to a specific element or feature of the structure rather than the structure as a whole.
5.5 Conversely the principal inspection regime can be extended beyond the 6 year period up to a maximum of 12 years for those structures that are of the lower hierarchy levels.
5.6 A revised inspection regime will only be implemented on completion of a risk assessment, used to quantify;
- The likelihood of rapid deterioration or other incidents; and
- The consequence of unchecked deterioration/incidents
Full details of the risk assessment process to be followed are given in the Well Managed Highway Infrastructure Code of Practice (Oct 2016) Sections C.5.2.28 to
C.5.2.30 and the Design Manual For Roads and Bridges, Volume 3, Section 1, Part 4, BD63 Inspection of Highway Structures.
5.7 The revised inspection regime and the reasons for its implementation shall be agreed with the Highway Asset Manager prior to implementation and is to be recorded in the relevant structures folder for future reference and information.
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