[Paul B]

There are a bunch of footbridges all along that river. It would really start to become a pain if more of them got inspected and condemned in that way. 

You mean based on the industry standard, derived from a boat load of analysis to derive the Euronorms (Eurocodes; BS EN)?

Let people not forget that these codes produce far leaner designs than their predecessors (BS) at the cost of being more complex for the designer.

Let me ask you this, as someone with a duty of "reasonable skill and care" which I would need to demonstrate if something went wrong, how would you suggest someone looks at a structure if not in a way which is industry recognised?

Are people genuinely surprised that the timber elements need replacing?

[stone]

I suppose, back in 2019, I was hoping that all the timber could have been stripped out and replaced with eg plastic fake timber like https://plastecowood.com/product/decking-support/.

I fully accept now that the steel is also rotten and so the situation is as it is. It is nevertheless a bad situation. We don't know at this stage whether there ever will be a replacement bridge.

Like I said I have reposted the donation link in several places so I'm hardly the arch naysayer.

I'm a bit aghast that the new bridge will include timber though.

I fully appreciate that civil engineers have very onerous responsibilities to not mess up and potentially kill people.

[Paul B]

In terms of cynicism, I suppose the counter question is are you really arguing that overengineering isnt a thing? Obviously sometimes it may be prudent, but surely sometimes it isn't and amounts to a waste. Im not an engineer and am 100% ignorant, but we were only allowed opinions on stuff we were experts in this discussion forum wouldn't be very populated!

I'm currently abroad, so I'll keep this relatively brief but using the example we have here of an engineer looking at an existing structure and applying standard practice then no, I don't think they're being overly conservative. The simple fact is if such an outfit were to waltz around condemning structures all day every day as they didn't want any risk themselves then they'd soon be out of business. Reports such as the one Remus linked often end up in the public domain but also, are given to people like Peewee (or a TAA; Technical Approval Authority where the client doesn't have that expertise) that'd go back and challenge wildly risk averse behaviour. In terms of the Eurocodes, they work based on characteristic values which should be 'moderately conservative'. For steel these are well documented and they are what they are, whereas for things like soils they're via testing and interpretation.

Now if we take the replacement bridge itself, the answer is again, no. Again, the simple fact is that if it was vastly over-engineered then there'd be someone coming in at a lesser price applying the standards correctly and the consultant/contractor would again find themselves losing out to others. Lose enough work that isn't fee-earning and you'll go out of business. Civil Engineers design to standards and they don't go around throwing in extra bunts to make themselves more comfortable. There are exceptions here where clients demand more than the standard. A quick example on a temporary condition is that one large infrastructure asset owner requires cranes operated on their sites to be at 90% of their duty (capacity) or less. They do this because many of the cranes used for BIG LIFTS are very very old and it protects against age related concerns. When I do a design for the contractor using that item of plant then I do it to the client's internal standards because if I don't then the lift isn't happening. Fitting a similar example to the bridge in question, you can deviate from 5kPa live loading via a formula in the DMRB but again, some clients state in their contracts / asset standards that they don't want you to do so. Things like this are their call so they don't have to give it a second thought when someone routes a running event over their bridges.

Where things get more complex is the palming around of risk and programmes that are a stretch to meet. I've sat in a few meetings rather smugly with a cup of tea watching a Geotech engineer who had their investigations stripped to the bone early in a contract show a chart based on the cost of investigation to a project vs. time in that project's life. The basics of this are people don't like doing Geo Investigation (GI) upfront to the correct level because it appears expensive. However, the expense is a fraction of the cost of learning the hard way when you're on site burning through cash. In this instance you might end up doing something expensive or on the face of it over the top to get out of a difficult situation because that's actually cheaper than sitting around designing the leaner solution.

More on this would be where information is lacking. As an example, the same infrastructure owner requires bridge abutments to be assessed for their stability when replacing the deck. This is because over time, abutments can move and the deck acts as a nice prop, until someone removes it (they learnt this the hard way). If there's no GI, then when I do such an assessment I need to use conservative assumptions. The end solution may be over the top compared to what's there but depending on programme (let's say you need to shut a portion of a rail network to do it) it's the least bad option. What I'm essentially arguing here is that when you have 'over-design' or overly conservative design it's because of unknowns that require a conservative approach or more often than not poorly managed risk. If there's something specific regarding civils work that you think looks wildly over-designed I'd be interested to know what it is although perhaps this thread isn't the place.

I could go on with this and obviously like all things in life, there are people who are good at their jobs and then there are others.

[Paul B]

I was interested in the last section of that report, 5.4 and 5.5, where they appear to suggest that remediation of the bridge could be an option at a cost of £50-80,000. It wasn't specified, unless I missed it, how long this might extend the lifespan of the bridge. Obviously if this only bought the bridge 10 years it wouldn't be worth it. In 5.5, they estimate the budget costs of the new bridge to be £80-120,000, quite a lot less than the £180k now quoted, which might grow further.

I've run out of time before it's time to hit the buffet again (how times change) but this made me chuckle. Again, the DfT looked into budget estimates and concluded that even people who know what they talk about have what they termed optimism bias, they suggested that reality was 1.6x the budget estimate and that was before material prices went mad.

For a quick thought on your whole life cost comparison, timber elements are usually stated to have a design life of 7-10 years in the framework agreements I've worked under. The design life for civil structures under the same frameworks is almost always 60 years (if not sometimes 100). Note that design life isn't asset life with the latter being extendable via appropriate and timely maintenance (the clause usually states "time to first major maintenance" or similar wording). Oh, and you'd end up doing a lot of the same consenting paperwork for working in/near a watercourse.

If I've been a bit crabby in my responses today it's because I'm on holiday and I'm being messed about by a prospective employer.

[spidermonkey09]

Not at all, interesting answers! Enjoy the buffet!

[Tony]

Now that everyone (even those tossers who don’t wish to admit it) agree that 180k for this new bridge is a completely reasonable estimate…

Please -especially those that may wish to climb at Moat Buttress- continue to donate to the PDNP Foundation's fundraiser for this at: https://shorturl.at/cesz8

If the 5% fee that the charity’s chosen donation platform extracts from the charity offends you so much,

You can also donate by:

Bank transfer to ‘Peak District National Park Foundation’, sort code 20-10-71, account 63364895, Barclays Bank, quoting Cress-brook Bridge
Cheque made payable to Peak District National Park  Foundation with your contact details and marked Cress-brook Bridge to Aldern House, Baslow Road, Bakewell, Derbyshire, DE45 1AE

However, if you want to add gift aid (giving them an additional 25%), you’ll need to email them for a gift aid form to complete. So just donate online it’s probably easier for everyone, you cheap f*cks. I bet you don’t donate anything anyway…

[petejh]

GB Climbing spent £320,000 in 12 months sending some self-important managers swanning off to some conferences and failing to send some young competition climbers to climbing competitions.

On that metric, £180k to build a footbridge that will actually deliver climbers to their aspired-to destination (for at least the next 60 years) seems reasonable in comparison. 


Also everything PaulB said.



edit so as not to trigger Tony: added 'for at least 60years'.

[tk421a]

The engineer's report did say the original design passed checks, so if the climbers with chainsaws turned up and brought 2no 406x174x54 UBs that would work.
A quick search found they only go up to 15.5m which would fit the main span. So just make sure you can lift the 837kg beam. They're only £2.5k+vat each.

[tk421a]

The swiss build great bridges....
https://salbitbruecke.ch/
Was 280k chf in 2010

[Bonjoy]

Again, the DfT looked into budget estimates and concluded that even people who know what they talk about have what they termed optimism bias, they suggested that reality was 1.6x the budget estimate and that was before material prices went mad.

This is why I hated working as an estimator in the rope access industry. On big projects you were always pricing competitively against other estimators. It was a lose lose situation with two types of estimator. The bad estimators who priced in everything and therefore lost the work on price, and the other bad estimators who knowingly or otherwise didn't price in everything and therefore put in the lowest bid and won, at a price where the company made a loss. There were no good estimators. Only bad estimators good at blaming project managers for the loss.

[Fultonius]

Again, the DfT looked into budget estimates and concluded that even people who know what they talk about have what they termed optimism bias, they suggested that reality was 1.6x the budget estimate and that was before material prices went mad.

This is why I hated working as an estimator in the rope access industry. On big projects you were always pricing competitively against other estimators. It was a lose lose situation with two types of estimator. The bad estimators who priced in everything and therefore lost the work on price, and the other bad estimators who knowingly or otherwise didn't price in everything and therefore put in the lowest bid and won, at a price where the company made a loss. There were no good estimators. Only bad estimators good at blaming project managers for the loss.

Bid low and squeeze the variations. That's the way to win work... (repeat work less so)

Makes me wonder if "3 competitive tenders" actually gets you good value for money... In my old place we didn't win a single competitive tender, all of our work coming from existing clients or word of mouth/enquiries for proposals. If I never have to submit a tender again I'll be a happy man!

[remus]

It seems like a huge issue in public sector projects too. Government puts huge contract out for tender, ridiculous low bid wins (government: "Look how much money we've saved!"), contractor fails to provide basic levels of service and either government shells out a load more cash so basic service can be provided or government is back in the same place it started, having to do the work at the original cost, but with a big bill for the contractor too.

[Paul B]

Again, I'm at the buffet so this reply will be brief. That's what you see as the public, but what underlies that issue is poor risk management on the client side (and probably a poorly written contract/works information).

Change or variations or compensation events or whatever you want to call it, as Fultonious suggests is another issue but people can't get away with it if risk is managed correctly and the contract is sufficiently robust. Plus, choose your contractor wisely. They aren't all the same in their behaviours.

[SA Chris]

This is why I hated working as an estimator in the rope access industry. On big projects you were always pricing competitively against other estimators. It was a lose lose situation with two types of estimator. The bad estimators who priced in everything and therefore lost the work on price, and the other bad estimators who knowingly or otherwise didn't price in everything and therefore put in the lowest bid and won, at a price where the company made a loss. There were no good estimators. Only bad estimators good at blaming project managers for the loss.

You just summed up my day job nicely. Although I think i am one of the better of a bad bunch.

[remus]

Again, I'm at the buffet so this reply will be brief. That's what you see as the public, but what underlies that issue is poor risk management on the client side (and probably a poorly written contract/works information).

Change or variations or compensation events or whatever you want to call it, as Fultonious suggests is another issue but people can't get away with it if risk is managed correctly and the contract is sufficiently robust. Plus, choose your contractor wisely. They aren't all the same in their behaviours.

In your experience Paul, are there clients who do these things well? I guess the examples that I see are where things don't go well, but is that common? How hard is it writing a tight contract?

[Will Hunt]

It seems like a huge issue in public sector projects too. Government puts huge contract out for tender, ridiculous low bid wins (government: "Look how much money we've saved!"), contractor fails to provide basic levels of service and either government shells out a load more cash so basic service can be provided or government is back in the same place it started, having to do the work at the original cost, but with a big bill for the contractor too.

These things often work on pain/gain contracts. Meaning that if the job is delivered under the quoted price the contractor keeps x% of the "gain"; if over-budget the contractor covers x% of the "pain". Becomes a bit academic (there might be limitations in the contract) if the pain is so huge that it becomes unviable for the contractor, as you might find on really big jobs.

[Paul B]

In your experience Paul, are there clients who do these things well? I guess the examples that I see are where things don't go well, but is that common? How hard is it writing a tight contract?

Absolutely. When people are doing things like replacing a rail bridge over a Christmas line block there isn't scope for things to get delayed and because of that things tend to be better managed. However, even within client organisations you get better/worse teams and a lot of it comes down to the overall 'mood' in the framework if one exists and personal relationships (contractors may be softer with clients in the early days of a framework and absolute b*stards nearing the end if they haven't won an extension). This swings both ways as well, not all clients are well behaved. Some clients have been burnt so badly that their modified contracts are absolutely unreasonably biased towards themselves.

Writing a tight contract is incredibly tricky. The contract law course I went on last started with "imagine your perfect date". The presenter then went around the room asking each person, one describing a nice restaurant and lots of wine, the other quite liking the 25/12 as Christmas meant family, and then finally he said he quite liked a plump medjool himself. Different people read the same thing and think something different. Personally this is why I really enjoy the contractual side of things but most engineers don't.

Will has summed up a common mechanism for driving cost savings / innovation etc. (usually there's pain and gain shoulders to prevent the process being manipulated). When client's are truly collaborative, in design & build frameworks with a fair allocation of risk (i.e. the person who can or should have managed a risk gets to own it) then things work very well. This can be as trusting as the contract saying "a footbridge at X has insufficient structural capacity" and little else apart from the standard contract options for things such as payment mechanisms.

If we use ground risk as an example again, the gov asks for let's say a new HS rail link, they don't have suitable GI so ask the contractor to give them a price. The contractor bundles a load of risk in their price (if they don't immediately say "no thanks" instead) and the gov b0rks at the price they're given. To 'reduce' the costs, the gov accept the ground risk themselves and that goes in as an additional employer's risk. A sensible person then puts the £ difference in a risk pot for a rainy day, a less sensible one pretends it isn't a real risk. The contractor then gets a fair way through designing and building said thing and realises that risk, submit a notice (early warning) and stick in a request for more money (compensation event). Outwardly all the public see is cost increasing and delay. This paragraph assumes a fair amount of things and is wildly simplistic but covers off why project costs always go up unless scope is reduced (negative comp event).

[Aussiegav]

I wonder if this is what happened to new university building opposite Weston Park hospital.
They were well into construction before having to completely demolish it and build a slightly different building

[Stabbsy]

I wonder if this is what happened to new university building opposite Weston Park hospital.
They were well into construction before having to completely demolish it and build a slightly different building

Off topic, but I think the design of the foundations was inadequate to support the building. There had been a reservoir on that site in the dim and distant past and the piling was maybe not deep enough. Not sure if this had been missed at the design stage and who ended up footing the bill.

[Johnny Brown]

Yes, once the steel was up and the floors were going in the surveyors picked up that it was subsiding. Perfect example of how spending a little more money earlier on would have saved a huge sum later.

[Aussiegav]

Back on topic.
If I remember correctly, there’s another way access to Moat Buttress & environs I appreciate this access isn’t as convenient, but climbing & walking is an outdoor pursuit?

Why not leave the bridge as it is?

[T_B]

You can walk in from Upperdale parking which adds 1km each way. Obvs no big deal if you have the time but I guess a lot of people going to the Cornice in particular warm up at Rubicon.

[remus]

I've climbed at moat quite a bit and walked in from the Litton mill side, it doesn't make that much difference time wise imo, but there's not much parking there so having the bridge is good for spreading cars out a bit.

[Johnny Brown]

Alternatively install a discrete single 8mm stainless wire between trees a little downstream? Harnesses on at the car park...

[SA Chris]

A rope swing is the only way! I've used the cable bridge in Boulder Canyon near Boulder, and with a pack on it feels scary, even with a harness..