I have been wanting to get some decent pictures of William Edward’s bridge in Pontipridd for some time (years). March provided an opportunity but it was cold and wet and the pictures weren’t that good so try again. What I did find, though, was this amazing effort from IKB. Can it be chance that it is the same span?
As you can see, a clear general arrangement is difficult. This is a substantial skew for a long and narrow bridge. You can also see that there is a lot going on round here. Widening this bridge with simple arches and a column half way is a bit hard to forgive but note there is another viaduct in the background so we had better fit in a map link. Note here, though, the water runs where the string course has been removed. They were not just decoration.
Sometime soon I will get some decent photos of the Edwards’ bridge but in the meantime there seems to be an element of Ginger Rogers in this IKBrunel effort - anything Edwards can do I can do skew and carrying a railway. At 140ft span it is the same as the older bridge. The elliptical shape is an alternative solution to the perforations, though again, the full detail of that will have to wait till I get to Edward’s bridge.
Looking from the other side we can see that the river is a long way down and this road has been inserted on a bridge of its own.
The little span on the right is interesting, we will come back to that. The two span, square widening is also quite unusual.
Here we are looking over the other side of the road, left is the new bridge, Brunel’s is to the right. It looks as though the weir in the previous picture has been badly eroded here.
The stone seems to be very hard. It is quite likely to be Welsh Pennant whh was quarried very near here.
Looking from downstream at the far springing, we see the little arch. It is now obvious that it is at springing level for the main arch and almost certainly there to resist the thrust, though the basic abutment is already quite large.
The joints are very tight, both on the intrados and the elevation. Dressing such hard and schistose stone to fit must have been very difficult.
The beds, though, are somewhat jiggly, so perhaps fit was hard.
On a bridge of this size, the HTA vehicles that are doing so much damage elsewhere would be relatively insignificant. I wasn’t able to measure, but it looks as though the rise is about 1/3 of the span so The unloaded thrust looks like this:
And loaded, like this. These are HTA vehicles which are typically used for movig coal and which were observed on the bridge.
So it isn’t surprising this shows no sign of deterioration, except the need to remove the string course where (presumably) some pieces broke off, or was it to protect the new road from falling stone?
All in all, that is quite a bridge. Just sorry it is so late but life is remarkably busy just now.