Thursday 31 July 2014

Thanks to the good weather, progress continues to be made steadily, and a further report can now be made after visits by our structures engineer and your scribe today.

Here we go, bridge by bridge:

Bridge 1, Broadway



The last and toughest part of the major works – the removal of the two riveted plates from the Evesham side outer main girder - has been completed.

Removed lower flange from the Evesham side. This was the tough one!
Site of the removed Evesham side flange plate.
Evesham side flange removed, with strike damage



Bolting up the new Broadway side flange
The old plates will be going back to the workshops this weekend, to act as templates for the manufacture of new plates. Bolting up of the similar new plates on the Broadway side is about 50% completed, as you can see in the picture above.

The cutting out of the 19 corroded areas of deck plates will be completed today. The new workshop made plates will be tacked into place, for safety reasons, by tomorrow night. These will all be fully profile welded next week.
 
Shaping the place for a new piece of deck plate.
 The corroded sections of all of the outer joggled stiffeners have been cut away (see photo of the typical corrosion result in the previous post), and most of those on the Broadway side girder have been welded and bolted back into place.

Work on straightening and repairing the impact damage on the minor members is also in progress.

John, our structures engineer, inspects the straightening of a minor frame member.
 A couple of historical items from this 1904 bridge:
BX and B1 are original factory markings from the construction of the bridge. They were found on the removed Evesham side main girder lower flanges, which were removed with considerable effort - see below.

A rivet from the Evesham side main girder
The picture above shows how rivets were removed that refused to yield to a 20 ton press - they were drilled out using a hollow bit. There was quite a sense of achievement on site today, now that this flange plate is off. It proved a tough nut to crack, but we got there.

Bridge 3, Pry Lane


Brick repairs and pointing are virtually complete to this bridge.


Bridge 5, Little Buckland


Excavation of the ground behind the north abutment, down to the level of the original abutment foundations, is now completed. Resin anchored dowel bars, to tie the new concrete to the old abutment brickwork, have been installed. All excavation is now complete at this bridge.
 
Broadway side abutment excavation
The full extent of the crack between the downside wing wall and the Broadway abutment, which we believe moved forwards about the time the bridge was first built, is now clearly exposed.

A large crack has been revealed after full excavation of the Broadway abutment, where the downside wing wall should be attached. This will be tied in to the big concrete block that will be poured here. It's not going to move any further!
Shuttering is being installed behind the Cheltenham end abutment ready for the second concrete pour:

Cheltenham end abutment, ready for the second concrete pour.
Low level shuttering is being installed on the line of the replacement wing wall on the upside, Broadway end, to form the stepped base of the new wing wall foundations. A combined concrete pour of the lowest section of concrete behind the Broadway end abutment and this wing wall, together with the Cheltenham end abutment pour 2, is planned for Monday next. This means a lot of concrete has to be bought!



You can see where the money is being spent, but the share issue is not yet fully subscribed. We are still £42.000 short. Please help if you can. Just fill in a form, send it with a cheque, and claim back 30% from HMRC. It works !

The prospectus with the form at the back can be downloaded here:
http://www.gwsr.com/BridgestoBroadway.pdf

Thank you for your help !

Monday 28 July 2014

Update as at close of play on Monday:

Bridge 5, Little Buckland:

Repaired wing wall, Broadway side


Further digging has gone on and now about 50% of the ground behind the north abutment has been excavated and carted away. 

Broadway abutment - 50% of the dig has been completed here.
Broadway abutment, with wing wall blinding in the foreground


At 12.30 today, they were pouring some “blinding” concrete, to the highest two stepped levels of the upside wing wall, which will support the new strengthening concrete and the replacement brickwork.  
Leveling out the blinding concrete.
The blinding concrete is to create a level surface on which the shuttering can installed. As many people will be aware the wing walls on all of our bridges lean backwards at a slope of 1 : 6, i.e. in a 3M high wall the top will be 500 mm further back than the base. The old wall on the upside, Broadway end, has been completely removed and will be replaced with a thick concrete wall, which will be faced with 225 thick Engineering bricks to match the other 3 walls.

To construct this wall, shuttering will be required to both faces to form the correct slope and thickness. 
The 'root' of the former wing wall
 This wing wall was in such bad condition, that it has been completely removed, right down to its foundations. These seemed to be made of crushed stone only, possibly with a weak mix to hold it.
Overview of the Bridge 5 works at the end of Monday 28th July.
Whilst these works were going on the Tramblast was busy applying undercoat and top coat to the steelwork there, mainly working below deck level.

Bridge 3, Pry Lane
At bridge 3 the bricklayers were cutting out defective joints in the brick arch and parapet walls, and then pointing them up.

Bridge 1, Broadway
A quickie visit, right at the end of the day, finds the steelworkers still hard at work, and very cheerful. They were happy to give your reporter 5 mins of their time.

So how have they been doing, since the last visit by our structures engineer John, 2 working days ago?
A new joggle plate
Back at base in Wales, they have made themselves a supply of these joggle plates. They connect the web of the main girder to the flange underneath. Most were badly moth eaten, so these nice new ones are being welded in. Below is one that they took out - can you see why?  :-)
Moth eaten joggle plate.
I asked ' so what have you been doing', and the answer is clear: This lower flange on the Evesham side girder has had a nasty cut from a strike, and has to come off. Taking off the similar plate on the Broadway side took 14 hours, as it was mostly a question of removing the bolts from the 1975 repair. However, the Evesham side is a different kettle of fish. This side was never repaired, so the original rivets are still in place.Getting these out has been very hard work, and is taking more than twice as long as the other side. After cutting off one end, they are being forced out with a 20T press, but even so the fit is so tight that some have to be drilled out from above. The numerous strikes have twisted the plates, and this has made the rivets even tighter. The decking below was peppered with old rivets, so plenty of progress is being made by these plucky lads from Wales.

Above is a twisted girder, well inside and underneath the bridge. It seems incredible that whatever struck the girder on the outside seemed to bounce down, and rear up again underneath for a second strike. It's just another job that will be tackled.

This is a view of such a 'second strike' girder, with its bottom flange removed. The web itself is intact, and will be pressed back into shape and a new flange attached underneath. All pukka stuff.

Finally, a quick look at the drilling out of reluctant and tight fitting rivets. This is done from above, with a magnetic drill. The rivet is removed by drilling out its centre with a hollow drill bit. Slow and steady, and we are getting a quality job here.

The next major development expected is pouring the concrete at Little Buckland. Monday 4th August looks like the day that this will happen.