Stanton aqueduct round up

BRIDGE 09 – AQUEDUCT/ PEDESTRIAN FOOTBRIDGE – FINAL REPORT

The Aqueduct/footbridge is now totally completed and the Public Footpath which it carries has now been re-opened. 

You can just about make out the timber fencing at each end on the south view photo.

Cotswolds bank seat as built

Cotswolds bank seat today

The main changes, since the last report, are to the east (Cotswold) bank seat. 

Costwolds side footpath entrance

Cotswold side landing area

This has been enlarged to provide a better entrance, with a new “landing” area. 

New timber fencing, here on the Malvern side

 All of the timber fencing around the Public footpath approach section at both ends has been replaced.

New grating

The inlet on the Cotswold side has been fitted with a grating. This end is now fixed so the joint between the steel box and the concrete approach channel should no longer leak. 

The final (not very clear) photo is of the Malvern end showing the rollers which retain the steel box but allow for movement due to expansion, which could total up to 25mm over the likely temperature range encountered in this country (minus 10 C to + 35 C). 

Heat absorption by the steel can add another 5C.

   

Inevitably, when working in November/December, there were a few problems encountered during the works:–

1.         Low temperatures slowing the off-site painting operation and some of the brick laying.
2.         The gales, which stopped the expensive 60T crane from being used for the steel erection work. Although excellent service using a large lorry with a very long reach Hiab crane was substituted, this was nowhere near as flexible. It involved some shunting of the lorry to and fro between lifts, to optimise the reach and angle needed. The short notice availability and reach issues probably added about 2 days onto the installation operation.
3.        The rain, which made access up the embankment difficult and caused delays in excavation, concreting and brick laying, and the final making good.

Fortunately, by very hard work and chasing around for alternatives, the Contractors were able to overcome all of these issues, and managed to get the line cleared in time for the northbound Santa trains to start on Saturday 8^th December, as originally programmed. The Contractors were finished just 2 days late, on the Tuesday night (11^th) and finally cleared all their welfare and storage cabins, waste skip and plant  site, from Stanton yard on Friday (14^th) leaving it a lot clearer than before they started (photo)!

Photos courtesy of Alastair Watson & John Balderstone.

16.12.2018 - JOHN BALDERSTONE

Fitting hand rails.

BRIDGE 09 – AQUEDUCT/ PEDESTRIAN FOOTBRIDGE – UPDATE TO 7.12.18

Completion is now very close, with the bridge steelwork being completed, checked and fit for use. 

All that is now left is to complete the timber fencing at both ends of the aqueduct and to have a final tidy up and remove all the plant (360 & dumper), site accommodation, cabins, skips, etc. The line has been completely cleared and north running Santa trains will be passing beneath the bridge today! By the end of next week the footpath over the bridge can be re-opened.

West end of the panelling.

Last week about 2/3rds of the parapet rails had been completed, but a larger crane was need for the remaining panels on the east end. Because continuing gales were forecast until about Wednesday, the contractor arranged for the larger lorry with the longest HIAB crane to come in on Monday. Unfortunately this was not available until about 14.00, which was OK as the erectors had a 4 to 5 hour journey back from North Wales. 

Parapet rail panels being erected

 

 

 

 

 

 

 

Last panel going in.

With fading light and being at the limit of the HIAB reach the last two panels were lifted in. Sounds easy, but trying to get 5 individual internal tube connectors to align whilst ensuring that the vertical standards were attached to the correct side of the bracket on the side of the box was an extremely difficult task! Fortunately the lights on the crane were very good – without them we would have needed part of another day. The last job was to lift the panels of flooring up to sit on the floor of the bridge, ready for laying.

Engineer checking splice joints

On the Monday afternoon the Engineer from Halcrow (Jacobs) came along to check the structure, particularly the splice joints and bearings on the piers. 

All was found to be sound! So on Tuesday the scaffolders came in and removed all of that equipment.

Aqueduct without scaffold.

On Tuesday the steelworkers then laid the floor panels and started to install the mesh panels to the sides. 

Smoke hood fitted.

By Thursday the structure was virtually completed, including the smoke hood. 

Smoke hoods are more often seen in station bridge locations, but inspection experience has shown that the worst corrosion occurs immediately above the centre of the track – clearly from steam loco exhaust emissions!

Completed walkway.

The next shot is of the finished bridge from the Malvern end at walkway level.

The final shots are of water coming out of the west (Malvern end)

and the shallow pond (app. 30mm deep) in the east (Cotswold) entry channel. 

The small step to the invert, when combined with the approx. 30mm step to the pipe invert through the new headwall from the field side, will, we hope, eliminate silting.

I am very pleased to report that it doesn’t leak!!!!!

Photos courtesy of Alastair Watson & John Balderstone.

8.12.2018 - JOHN BALDERSTONE

Replacement aqueduct is lifted in

BRIDGE 09 – AQUEDUCT/ PEDESTRIAN FOOTBRIDGE – UPDATE TO 30.11.18

Progress has been good, despite the weather getting wetter and with the contractor having to start work on the car park entrance at Broadway as well, at very short notice!  

The shuttering around the east bank seat has now been removed making it ready to take the new aqueduct steel box section.

 

 

The west bank seat had to be broken out to release the old steel channel and to make it wider for the slightly larger new steel box section. The rougher breakout areas have been made good with concrete repair materials.

The steel was due to arrive from North Wales on Wednesday, but due to problems with delays in painting (because of the cold weather) and loading it did not arrive until after 18.00, so the transfer of the steel up to the bridge site did not happen that day, as was intended. Then to compound the problems, when the 60 T crane arrived at 8.00a.m. on the Thursday morning, the wind was gusting at up to 45 MPH and as the crane could not be permitted to work in winds over 22 MPH the whole lifting operation was cancelled!! The Met office forecast was indicating that gales were to be expected right through to Tuesday night, so a disaster was looming!

Fortunately, and at extremely short notice, the contractor managed to obtain a very large flatbed lorry with a Hiab crane, which arrived about midday on Thursday. The Hiab had a lifting capacity of 3.5T at 16M radius, which was amazing! Because the artic lorry delivering the steel to site was too large to get up to the bridge site the steel all had first to be transferred onto the Hiab truck.

 

The sections were then taken up to the bridge site, a bit at a time. The Hiab lorry had a rear extension section which could be pulled out to support the sections up to 12M long. This Hiab lorry was not limited by wind speeds and so, once the artic had been unloaded, the bridge steelwork installation could be started. 

 

The first length to be lifted was on the east (Cotswold side).

Next was the centre span. Unfortunately neither Alastair nor I were there to see the west (Malvern) span lifted into place.

The new entrance on the downside fitted into the slot to become a “fixed” end to stop movement where the stream channel joins. A small step has been included to stop silt being washed into the steel box. Another small step has been provided at our boundary fence to provide further protection against silting.

Ironically, despite having provided a piped diversion for the stream, not a drop of water has come into the channel yet!!

Handrails waiting to be lifted on.

The following day a different Hiab lorry came along and had started lifting handrailing into place before I arrived and so that on the Malvern end, the north side was already in place. 

The south side, west end panel of handrailing was then lifted in, 

followed by two of the toe kicker angles.

The final two photos show a close up of one of the two splice joints, and the west side end of the new channel.

Photos courtesy of Alastair Watson & John Balderstone.

1.12.2018 - JOHN BALDERSTONE

Aqueduct update

BRIDGE 09 – AQUEDUCT/ PEDESTRIAN FOOTBRIDGE – UPDATE TO 20.11.18

With the aqueduct/bridge gone, the poor condition east end bank seat was carefully demolished.

and the old foundation widened with extra concrete to the front and both sides. 

Next the main bearing block was concreted; the enlargement of the base, underneath, can just be seen. 

Then the two side blocks were concreted.

The stream coming in from the field on the Cotswold side, into a concrete filled brick sided channel has always been a mess. The old concrete had a substantial dip at the centre causing the water to lie there. 

So that was all cleared away and a new one built with a pipe into the ditch in the field. 

The photograph shows it almost finished.

BRIDGE 12 – VIADUCT – PRINCIPAL INSPECTION (continued)

With 7 of the arches having been inspected with a MEWP a couple of weeks ago, the next task was to inspect the parapet walls and the spandrel brickwork. This was to be done by rope abseiling men. 

The ropes were anchored to the track, 

 

and then the men hung from the top of the parapet doing the inspections. 

The remaining arches were also to be done by aerial rope workers.

In this case a main cable was laid right around and through the viaduct arch, and was then pulled tight below the crown, being anchored to the track from both sides. Then the men attached themselves to this main cable and pulled themselves along.

 



Photos courtesy of John Balderstone and John Fancote.

20.11.2018 - JOHN BALDERSTONE