Stone Arch Bridge Repair

[scr82566]

Does anyone have any experience with repair of a stone arch bridge with failing spandrel wall? The structure is over 100 years old and one of the spandrels is bulging to the point where failure is a concern. The repair itself is fairly straightforward, however the client is requesting the road stay open to traffic on one side while the spandrel is repaired on the other side. The height of the spandrel wall is 18 ft so sheeting will be required to excavate and repair, which I'm not sure how to address. I also have some concerns with unbalanced loads over the barrel as half the fill will be removed during the repair. Any input would be appreciated.

 

[Lomarandil]

I've only been slightly involved with one stone arch (a long time ago), but recently worked on a concrete arch bridge from about that long ago. It was also a partial repair/replacement.

I'm not sure what you mean by sheeting -- is that another term for falsework perhaps?

You're right to be concerned about the unbalanced barrel load. All depends on the specifics of your arch -- even in concrete, some are resilient enough to handle it, but many aren't without some sort of temporary shoring/falsework. Definitely will require some analysis.

 

[oldestguy]

Before doing anything, I'd install a series of reference points in the arch, and have a convenient way to know or measure their positions before and during the work. Let's suppose some uneven loading takes place, and visually no "sign" of movement occurs. You would want to be able to take corrective action before it is too late.

 

[bridgebuster]

Deja vu all over again, sort of. In 1994 I developed preliminary plans to rehabilitate a concrete spandrel arch with concrete walls and stone facing. The span is about 120' and the rise is about 35'. I'm glad it's still in preliminary design. A few thoughts:

Two excavation operations have to take place simultaneously to maintain a balanced condition. In reality it probably won't happen.

Driving sheeting is risky, as in driving it through the arch. Also, how do you brace/anchor the sheeting? You need dead end in front of the sheets or dead men and tie rods behind the sheets, in the area that has to remain open. On the project I worked on, we decided to use a single lane, two span temporary bridge rather than trying to install sheeting; the sheeting installation sequence was getting unwieldy.

Have you looked at Cintec.com? They have proprietary masonry anchors that can be drilled and grouted. Also, in the Jan/Feb 2002 edition of ASCE Journal of Bridge Engineering there was an article about restoring 120 year old stone bridge piers with high performance grout. A few years ago there was a large stone gravity retaining wall in NYC that was reinforced by a series of vertical pin piles installed in a grid.

 

[dik]

Check with the University of Sheffield for a program called Ring

http://www.ring.shef.ac.uk/

 

[DBronson]

scr82566:

Jaques Heyamn's book "The Masonry Arch" deals with that problem. Also, you might investigate John Ochsendorf's masonry web site at MIT.

Link

Regards,

DB

 

[scr82566]

Thanks to all for the input. It's much appreciated.

 

[SLTA]

This book may also have some useful information. Good luck!

https://www.amazon.com/Safety-historical-stone-arch-bridges/dp/3540776168

Please remember: we're not all guys!