- Initial version.
- 2023-03-29. Added videos of "New Thoughts about Old Bridges" presentation and a video summarising some guidance prepared for Network Rail, "Common Damage in Masonry Viaducts."
ICE paper: On the service behaviour of masonry viaducts
Railway viaducts are suffering damage short of collapse that is not predicted by current assessments, but which requires major interventions. This is a critical issue facing the UK rail network, where freight traffic is growing rapidly.
It is important that anyone conducting assessments of masonry viaducts, especially under-line rail structures, understands these issues. This page links to various some material on the subject.
This paper (ICE Publishing, open access) offers a new understanding of critical behaviour, which is not dominated by arching. Rather, the main section over each pier and extending well into the span either side behaves as a rigid block, rocking back and forth as loads pass. This behaviour explains spandrel cracks and horizontal cracks in spandrel walls and below parapets, which are both frequently seen in arch viaducts. With further research, including field measurement of behaviour under normal traffic loads, this understanding should lead to useful assessment guidelines and new methods of strengthening and repair.
The reference details and link are:
The following webinar, prepared by Bill for ICE Wales, covers the same material and more, and includes videos that better illustrate some of the points.
Common damage in masonry viaducts
There is a range of damage that occurs frequently in masonry viaducts. We believe that much of it is driven by the behaviour described above. The following two videos are based on guidance prepared for Network Rail. The reporting system referred to at the end has not come to fruition.