Promenade - Megathread

[Banker]

Well all stopped for another few months FFS!!

[ellanvannin2010]

18 minutes ago, Non-Believer said:

Relaying of block work "not down to subsidence" but blocks to be relaid on different substrate. Blocklaying contractor's responsibility.

DOI workforce did the bit at Senna Slip though AFAIK.

In that case the DOI will pay for it to be done again then, how is that at no cost to the taxpayer?

Edited March 5, 2021 by ellanvannin2010

[Pipsqueak]

13 minutes ago, Non-Believer said:

 

Relaying of block work "not down to subsidence" but blocks to be relaid on different substrate. Blocklaying contractor's responsibility.

i liked this one,   it wasn't subsidence,  if the foundations/substrate have moved and the blocks have moved that IS subsidence in  my books.

[CallMeCurious]

1 hour ago, ellanvannin2010 said:

DOI workforce did the bit at Senna Slip though AFAIK.

In that case the DOI will pay for it to be done again then, how is that at no cost to the taxpayer?

It would cost us the same whether they were working there or on another DoI project goes the Government logic. However, when you don't have the resources and time to do that other project and get outside contactors in. Then that is an extra cost but it can't be attributed to the Promenade directly so hey presto problem solved. 🙈  

Edited March 5, 2021 by CallMeCurious
spelling

[Numbnuts]

1 hour ago, ellanvannin2010 said:

DOI workforce did the bit at Senna Slip though AFAIK.

In that case the DOI will pay for it to be done again then, how is that at no cost to the taxpayer?

Your not supposed to notice that ! Yes I dont get it either as they say it often . We are paying twice for sure .

[AlanShimmin]

On 2/25/2021 at 9:11 PM, CallMeCurious said:

Don't recall where I heard/read it but I've always been of the opinion that wanting to be a politician should automatically exclude you from being one. Do it like jury service. You get a 4 year stint on a good salary and that's it. No return. Standard exclusions for armed forces, services, etc.

Never happen of course. Turkeys don't vote for Christmas.    

Sortition. It has a lot going for it. 

[Boris Johnson]

2 hours ago, Non-Believer said:

Latest from Prom meeting minutes on iomtoday.

 

Repairs to red concrete cracking not looking good, Auldyn's responsibility.

 

Anyone with any engineering understanding will know the red concrete has cracked because of bad design, not Auldyn.

Concrete shrinks as it "sets" or more correctly cures, this will always cause cracking unless the width of the poured bay is roughly equal to the length OR it is full of rebar/ mesh to stop the shrinkage.

On the prom design the bays of concrete were far far too long in comparison to their width AND there was no rebar/ mesh AND when they did put some rebar/ mesh in it is FAR FAR too light a gauge.

I am pretty sure casting it against a rail that expands at a different rate to the concrete will also not be good design but cant say for sure on that point.

 

ETA Auldyn have built some of the best engineering projects on the island, do you really think they have become incompetent just when this job started?

Edited March 5, 2021 by Boris Johnson

[TheTeapot]

4 minutes ago, Boris Johnson said:

Anyone with any engineering understanding will know the red concrete has cracked because of bad design, not Auldyn.

Concrete shrinks as it "sets" or more correctly cures, this will always cause cracking unless the width of the poured bay is roughly equal to the length OR it is full of rebar/ mesh to stop the shrinkage.

On the prom design the bays of concrete were far far too long in comparison to their width AND there was no rebar/ mesh AND when they did put some rebar/ mesh in to is FAR FAR to light a gauge.

I am pretty sure casting it against a rail that expands at a different rate to the concrete will also not be good design but cant say for sure on that point.

There did seems to be a fair bit of rebar going into the bays from what I saw, although I rarely go to Douglas and maybe it was just on a good day.

Your last point is a major problem in my view.

They also poured the concrete, and then smashed the roads out either side. Those big vibrations through still curing concrete will not have helped. At all.

[Two-lane]

There is a 6 or 8 inch thick concrete slab beneath the rails - that is there to take the weight of an electric tram. But I do not understand the need for red concrete as the top surface. Is there a technical reason for this - or is it just to make the road surface a different colour? If so, could they not just have laid tarmac and painted it red?

[Boris Johnson]

1 minute ago, TheTeapot said:

There did seems to be a fair bit of rebar going into the bays from what I saw, although I rarely go to Douglas and maybe it was just on a good day.

Your last point is a major problem in my view.

They also poured the concrete, and then smashed the roads out either side. Those big vibrations through still curing concrete will not have helped. At all.

There was quite a bit of bar/ mesh just not enough.

[Boris Johnson]

2 minutes ago, Two-lane said:

There is a 6 or 8 inch thick concrete slab beneath the rails - that is there to take the weight of an electric tram. But I do not understand the need for red concrete as the top surface. Is there a technical reason for this - or is it just to make the road surface a different colour? If so, could they not just have laid tarmac and painted it red?

Its decorative and the cracks don't really matter for strength, just looks. Tarmac would have been better.

[finlo]

11 minutes ago, Two-lane said:

There is a 6 or 8 inch thick concrete slab beneath the rails - that is there to take the weight of an electric tram. But I do not understand the need for red concrete as the top surface. Is there a technical reason for this - or is it just to make the road surface a different colour? If so, could they not just have laid tarmac and painted it red?

Or used red tarmac even.

[Two-lane]

11 minutes ago, Boris Johnson said:

Its decorative and the cracks don't really matter for strength, just looks.

It seems to me that a not insignificant part of the cost and problems of the northern end of the prom. is down to the requirement for red concrete - which is probably an unnecessary feature.

You might also consider the cost of the concrete plinth which, as I mentioned, is there to take the weight of an electric tram. To run the trams, there would  also need to be an additional significant cost for installing the overhead wires.

Trams are damn dangerous. Flanged steel wheels running on steel rails do not break bones, they slice off bits of limbs - which is why modern trams have skirts down to ground-level. The MER is allowed to run at the moment because of grandfather rights. If the MER line was extended down the prom., it would be a new installation but would not pass up-to-date safety requirements. But presumably Longworth would insist that an exemption be issued.

But... all it would take would be for one lycra-lout to take a tumble in front of a tram and lose a hand or a foot, and the tram would never run again on that section. And all that construction money is wasted.

[Numbnuts]

1 hour ago, Boris Johnson said:

Anyone with any engineering understanding will know the red concrete has cracked because of bad design, not Auldyn.

Concrete shrinks as it "sets" or more correctly cures, this will always cause cracking unless the width of the poured bay is roughly equal to the length OR it is full of rebar/ mesh to stop the shrinkage.

On the prom design the bays of concrete were far far too long in comparison to their width AND there was no rebar/ mesh AND when they did put some rebar/ mesh in it is FAR FAR too light a gauge.

I am pretty sure casting it against a rail that expands at a different rate to the concrete will also not be good design but cant say for sure on that point.

 

ETA Auldyn have built some of the best engineering projects on the island, do you really think they have become incompetent just when this job started?

This is correct and clearly there has been spec and design issues . I've kept a eye on the prom works as most will know and the rail laying from the first lengths by Strathalllan was laid direct and fixed directly to the concrete slab underneath . First cracking , then the next span they changed the spec and put spacers under the rails so they weren't in direct contact with slab. Still cracks so next they changed the mesh size , changed the method of fixing into the concrete base and also started to leave a small gap between rails and red concrete . And so it goes on to this day . This clearly in my reading of it is down to engineers and design and not Auldyn as no main contractor would go off spec with this sort of issue. My reading is Auldyn did to spec , it was found to be inadaquate and it was changed by designers/ engineers and again failed and again changed . I would say though that there doesnt seem to be a full time clerk of works on site or similar which is asking for problems. There has also been issues with expansion joints and initially none were put in and they used a grinder to try and introduce some. Later they put them in far closer and mesh size and rebar was far greater thna earlier efforts . Design in my view is flawed big time . I would add that the red concrete in many cases was put down in very hot weather , later in the day and not wet down during the drying process which wont have helped .   

Edited March 5, 2021 by Numbnuts

[quilp]

Since the very start of the project I wondered about the curing environment for the laid concrete. Plenty of info out there on this subject...