PS: Asset Management of Masonry Arch Bridges

Question 1

Describe an integral bridge

Answer 1

No bearings or joints between the superstructure and substructure

Problems with integral bridges usually come from this*

Question 2

Describe the asset management lifecycle

Answer 2

1. Desk study of records
2. A series of inspections, every two years
3. Structural review, to consider whether load assessment needed
4. Inspection (intrusive and non-intrusive)
5. Sampling and testing
6. Load assessment
7. Assessment report submitted to client, with observations, conclusions and recommendations
8. If inadequate, bridge use must be restricted
9. If adequate but deteriorating significantly (e.g. Hammersmith Flyover), SHM should be considered

Question 3

What must asset management be?

Answer 3

Continual

The need for intervention must be planned, rather than caused by unexpected events

The process must gather knowledge and improve understanding over time, throughout the life of the asset

Question 4

What are masonry arch bridges reliant on (three things)?

Answer 4

Reliant on external restraint (in the longitudinal direction), provided by supports

Reliant on arch thrust and compression as primary source of load capacity

Reliant on masonry bond for integrity, thrust distribution and shear distribution

Question 5

What is an example bridge that underwent asset management?

Answer 5

Helens Bay Bridge (NI, 2021)

• Stone arch rail underbridge
• Temporary support used and fortnightly monitoring
• Load assessment found adequate load capacity
• Recommendations proposed for action to remove the risk of dropped stones decaying further
• Rail traffic still running, water is still seeping through the masonry joints in the intrados
• The dropped stone area and supports are inspected fortnightly