Replacing single lane bridges

[Okey Dokey]

NZ Transit is undertaking to replace two old single lane bridges across the Waitaki River with two new single lane bridges. These are near Kurow, and connect SH 82 and SH 83.

I was quite surprised that anything other than a two lane bridge would be installed in this day and age. On their website, NZ Transit say they consider single lane bridges sufficient, due to low traffic volume and the extra cost involved in building a two lane bridge.

What do other kbers think about this in general? Our roading infrastructure always seems so patched up and short-sighted. Do you think it is okay to put up new single lane bridges on State Highways? Has this happened recently in other provincial areas, like the West Coast?

I'm interested in your views.

[idb]

I don't see it as a biggie personally.
I've never had to wait for streams of traffic across there.
I'm pretty sure they actually used to be road/rail bridges and you had to look for trains as well!

[Okey Dokey]

I'm pretty sure they actually used to be road/rail bridges and you had to look for trains as well!

Yes, that is correct.

Although these are the bridges I'm aware of, I meant my query in a more general way. Is this (single lane bridges built instead of two lane bridges) another example of short sighted roading projects? Does it save that much money? Someone in engineering or construction may know the relative costs.

I find single lane bridges "quaint", but just didn't expect that they were still being constructed...

[jim.cox]

NZ Transit is undertaking to replace two old single lane bridges across the Waitaki River with two new single lane bridges.
...
What do other kbers think about this in general?


One lane bridges are just accidents waiting to happen.

They dont belong on state Highways at all

Transit should not be building them - they dont save that much

Transit should be actively replacing all of them

It is just typical NZ poor engineering practice

[BOGAR]

From the point of view that a bridge hopefully has a long life and that there is always going to be an increase in traffic, eventually the single lane bridge wont suffice to the amount of traffic. But costs still need to be considered and the future life may be set to 10, 25 or 50 years and a estimated traffic growth vs cost is based on that. So if the bridge is only given a 25 year life (even though it would actually last longer) and the traffic growth in that time will not go above a threshold the calculations for a two lane bridge will not make the project viable. ( NOTE this is not 100% correct but hopefully explains what i see in my job with projects like these).

[Badjelly]

Transit should not be building them - they dont save that much

How much? Can anyone tell me how much a typical short bridge costs, one lane and two lane?

[jim.cox]

How much? Can anyone tell me how much a typical short bridge costs, one lane and two lane?

In myexperience, the saving is around 25% to 30%

[Ixion]

What is the problem with them ?

[BOGAR]

Struggling to find exact info but got this.
I think they are for single lane bridges

Standard bridge beams 6x26m Single pile and hammer head 3.5m $1.4 million
Continuous steel truss (concrete deck) 5x32m Single pile and hammer head 3.5m $1.76 million
Cable-Suspension
(Steel towers, steel truss and concrete deck) 20,120,20 Pile groups 3.5m $3.04 million

There are a menagerie of other factors that influence cost of options. (earthworks and piped services infrastructure are excluded in the prices above).

[Badjelly]

It seems to me single-lane bridges fit nicely into Ixion's programme oif making the roads seem more dangerous than they are, thereby encouraging observant driving.

I myself don't see a big problem with them if traffic volumes aren't too high.

[Badjelly]

In myexperience, the saving is around 25% to 30%


Struggling to find exact info but got this.
I think they are for single lane bridges

Standard bridge beams 6x26m Single pile and hammer head 3.5m $1.4 million
Continuous steel truss (concrete deck) 5x32m Single pile and hammer head 3.5m $1.76 million
Cable-Suspension
(Steel towers, steel truss and concrete deck) 20,120,20 Pile groups 3.5m $3.04 million

There are a menagerie of other factors that influence cost of options. (earthworks and piped services infrastructure are excluded in the prices above).

So, a bridge costs about $2 million, and single-lane saves you about $0.5 million compared with double-lane. That's a reasonably significant amount of money to me, and it may be better spent elsewhere in the roading system. So single-lane bridges on low-volume roads seem fair enough to me. :cool:

[sunhuntin]

i dont mind them if they are short [like say, 2 or 3 car lengths] but anything longer than that should be 2 lane.

[Trouser]

Have they replaced the single lane bridge on SH1 south of Cheviot?

Must be next on the list or are they saving it as a quaint reminder of the distant past?

[Kickaha]

Have they replaced the single lane bridge on SH1 south of Cheviot?


No........

[Ocean1]

I'm pretty sure they actually used to be road/rail bridges and you had to look for trains as well!

And traffic control was a train timetable nailed to the bridge.

Did wonders for literacy and numercy.

Nothing much for NZR's reputation for making the trains run on time though.

Then they went and spoiled it by putting red stop lights on them.

[jim.cox]

So, a bridge costs about $2 million, and single-lane saves you about $0.5 million compared with double-lane. That's a reasonably significant amount of money to me, and it may be better spent elsewhere in the roading system. So single-lane bridges on low-volume roads seem fair enough to me. :cool:

Any one fatal accident at $795000 (refer Tranist EEM2006, cost per fatal, all sites) during the life of the bridge and any saving is gone....

[jim.cox]

And traffic control was a train timetable nailed to the bridge.


And dont get me started on the crazy way they sign single lane brigdes -

Why they dont use a "proper" giveway sign is beyond me.

[sunhuntin]

And dont get me started on the crazy way they sign single lane brigdes -

Why they dont use a "proper" giveway sign is beyond me.

thats why they worry me. i know i understand what it means, but i dont know that joe tourist coming the other way knows. specially on the long ones.

[Ixion]

Any one fatal accident at $795000 (refer Tranist EEM2006, cost per fatal, all sites) during the life of the bridge and any saving is gone....

How many fatals are there a year on one lane bridges? Can't say it's near the top of my subjective list.

[Skyryder]

What is the problem with them ?

I think they are past their used by date. I could come up with a more cynical response tourist related but I think that subject's past it's use by date too.:Offtopic: Might be something to do with piles. But lets not go there either.


Skyryder

[Skyryder]

And dont get me started on the crazy way they sign single lane brigdes -

Why they dont use a "proper" giveway sign is beyond me.

Becasue some dumb tourist :stupid:will look to left and then to their right see nothing coming and proceed in front of a bloody big logging truck. :laugh:

Skyyrder

[Okey Dokey]

Thank you to everyone for your thoughts and information. JimCox and Bogar, your input about costings, etc was really great.

Ixion raised the point of what is wrong with single lane bridges. I didn't think of this as a good/bad value judgement initially. Although I do see a two laner on a SH as being "better", so maybe I am just splitting hairs.

Our population in NZ has grown and I expect it to continue to grow. A bridge is a long term project; the ones I mentioned in my OP are over 40 years old. These bridges are at the end of their lives, so it is not just an upgrade; it is a job that has to be done. I think a single lane option is a false economy in this day and age.

I am talking about SHs here, not secondary or rural roads. Just want to make that distinction.

I've lived in Europe and North America and I haven't seen single lane bridges being installed in these places. If I'm mistaken, I know someone will correct me! Are we such a poor nation that we still have to consider a single lane bridge as a cost saving option?

The cliche "If a job is worth doing, it is worth doing well" sums up my feelings pretty well.

Thanks again for all the input. It has helped clarify my thoughts on the issue.

[sunhuntin]

there are 2 on the west coast [south island] just south of hokitika. long horrid things with ridges like train tracks across at least one of them. _intense_ told me about them when we met up down that way.

[MotoGirl]

How many fatals are there a year on one lane bridges? Can't say it's near the top of my subjective list.

Considering the placement of some of these bridges, I'm surprised there aren't more fatalities. It's a wee bit silly to put these bridges on blind corners and use mirrors that turn to rubbish when it's wet or frosty.

[Okey Dokey]

there are 2 on the west coast [south island] just south of hokitika. long horrid things with ridges like train tracks across at least one of them. _intense_ told me about them when we met up down that way.

I guess what I was trying to ask is if/when they come due for replacement, will they put in ANOTHER single laner or opt for a two laner. I wondered if anyone had seen a single lane bridge put up on a SH recently.

The ones across the Waitaki are 250m and 150m long.

I think all our SH bridges deserve to be two laners; once they are erected I daresay they won't be replaced for another 50 or 100 years so I wish they would just do it properly in the first place...

[sunhuntin]

the two im thinking of should definately be 2 laned. i was petrified the whole way across. at least one had a layby area that stuck out on the side of the bridge. im picking it was to let other traffic pass safely, but if they are going to do that, why not just make it 2 lane in the first place?

[Okey Dokey]

Apologies for the thread dredge, but I have an UPDATE!

"after a cost analysis and lobbying from the community, the agency has decided to build two-lane bridges."

The article in the ODT goes on to say that the increased cost is not substantial for the two-lane vs one-lane, and it would be a better standard.

Thanks again to the contributors to this thread who helped me construct my submission. I am really happy with the outcome.

Construction to replace the 129 year old bridges "may" start in 2012, so don't expect to see them too soon.

[R6_kid]

It only takes one fatal accident on a single lane bridge to make two-lane bridge financially viable.

[crazyhorse]

There are about 3 one-lane bridges on SH 50 from Hastings to south of Waipukurau, and one of them has a 35km corner as you exit the bridge. This road is heavily used by trucks - milk tankers, sheep trucks, logging trucks etc. Its also the quickest route for Napier people travelling south. So this road is used extensively.

Doubt they will change these bridges....ever! Does make you wonder when you see the volume of vehicles using this road.

And 500k (the difference between the 1 and 2 lane) would hardly make any difference to any roading budget - probably only seal a 100m length of road :lol:

[yungatart]

There are about 3 one-lane bridges on SH 50 from Hastings to south of Waipukurau, and one of them has a 35km corner as you exit the bridge. This road is heavily used by trucks - milk tankers, sheep trucks, logging trucks etc. Its also the quickest route for Napier people travelling south. So this road is used extensively.

Doubt they will change these bridges....ever! Does make you wonder when you see the volume of vehicles using this road.

And 500k (the difference between the 1 and 2 lane) would hardly make any difference to any roading budget - probably only seal a 100m length of road :lol:
I regularly travel this road...I don't see the one lane bridges as an issue at all. The traffic volume is not particularly high, really. I think I have only had to give way about half a dozen times in many years of using this road.
It all comes down to being aware, I guess.....

[crazyhorse]

I regularly travel this road...I don't see the one lane bridges as an issue at all. The traffic volume is not particularly high, really. I think I have only had to give way about half a dozen times in many years of using this road.
It all comes down to being aware, I guess.....

There have been days when I have travelled down this road and had about 6 milk tankers ahead of me and heaps of traffic. Especially after Christmas. Maybe it depends on time of day travelled. But I could count the cars on one occassion and it would've exceeded a huge number - and no! not because I travel at speed, but because I was travelling a consistent pace and the cars were bumper to bumper that day

[Mully]

Isn't there a thing in the RMA that "Like can be replaced with like" with less hassle/cost?

That would mean they would have to consult with the locals, Iwi, DOC, and so on to build a bigger (2 lane) bridge, wouldn't it?

And given NZ is a country of NIMBYs, a bridge replacement could end up costing many time the budget.

[Skyryder]

And traffic control was a train timetable nailed to the bridge.

Did wonders for literacy and numercy.

Nothing much for NZR's reputation for making the trains run on time though.

Then they went and spoiled it by putting red stop lights on them.

Yep and the train whislte did not help.:rofl:

[Okey Dokey]

I'm not sure the RMA applies to Transit? Someone here undoubtably will know more than I do about this . Consultation was already being done- that is how I made my submission to the original suggestion of a one-lane bridge. I still think it is the correct decision in this day and age.

[Skyryder]

NZ Transit is undertaking to replace two old single lane bridges across the Waitaki River with two new single lane bridges. These are near Kurow, and connect SH 82 and SH 83.

I was quite surprised that anything other than a two lane bridge would be installed in this day and age. On their website, NZ Transit say they consider single lane bridges sufficient, due to low traffic volume and the extra cost involved in building a two lane bridge.

What do other kbers think about this in general? Our roading infrastructure always seems so patched up and short-sighted. Do you think it is okay to put up new single lane bridges on State Highways? Has this happened recently in other provincial areas, like the West Coast?

I'm interested in your views.

Typical short sightedness. They will regret this when 'Yodney' does his amalgamation thing down here and traffic volumes increase.

Skyryder

[Okey Dokey]

I have to agree with you there; I feel sorry that the whole Supercity concept is being forced on people. Especially the outlying rural-ish areas who have asked repeatedly to opt out. Is this democracy?

[Mully]

I'm not sure the RMA applies to Transit?

You're clearly not familiar with the taniwha (ahem) which forced the Waikato Expressway to be delayed and rerouted.

[Padmei]

I had a head on accident about 10 years ago on a one lane bridge. It was MY fault -going too fast for the conditions (other contributing factors as well). I could've killed my 2 work colleagues & the driver of the other car. Up until that point in time I didn't really have a problem with them and regarded them, as someone previously posted, as a quaint part of our road engineering history. Since then they give me the shits especially if I'm not driving & the driver is going over 5kph!
I questioned after that why go to effort of making a bridge 1m narrower to save a few pennies.
I welcome the decision to upgrade the bridges to 2 lanes & hope the ones on the main highway to Chch are the first to be replaced.

[Okey Dokey]

Thanks, Padmei, and sorry to hear of your crash. I know you would like to see the ones on SH1 sorted, but the ones over the Waitaki are ancient, paved over railway bridges that have buckled when the river is flowing strongly. Coach buses have refused to go over them for years due to safety concerns (for a while they actually made passengers get off the buses and walk across, then drove the bus over and let them get back on!)

They are going to be closed for a week in Feb, 7am-7pm while maintenance is done replacing planks, etc. Same thing happened a year ago. Locals can cross on the hour only during this time. This is not an "upgrade", this is a long neglected fixing of a serious problem.

[Chooky]

Yer, they are replacing our one. Its 80 years old, 470 meters long, carries heaps of traffic, but has no weight or speed restrictions on it..

192965

[Okey Dokey]

You're clearly not familiar with the taniwha (ahem) which forced the Waikato Expressway to be delayed and rerouted.

Oops, I had forgotten all about that!

[oldrider]

NZ Transit is undertaking to replace two old single lane bridges across the Waitaki River with two new single lane bridges. These are near Kurow, and connect SH 82 and SH 83.

I was quite surprised that anything other than a two lane bridge would be installed in this day and age. On their website, NZ Transit say they consider single lane bridges sufficient, due to low traffic volume and the extra cost involved in building a two lane bridge.

What do other kbers think about this in general? Our roading infrastructure always seems so patched up and short-sighted. Do you think it is okay to put up new single lane bridges on State Highways? Has this happened recently in other provincial areas, like the West Coast?

I'm interested in your views.

I was as dismayed as you appear to have been, when I read that press release!

Single lane bridges at major junction's, how short sighted can you get!

With respect, I doubt idb has used that bridge enough lately to appreciate just how much heavy traffic goes through there!

I think that will increase substantially with a new two lane bridge, once it is open for traffic, especially at night!

Had project Aqua gone ahead (Aqua was stopped by lack of foundation material, rather than protest action) the bridges would have been replaced by the project and at Meridian Energie's (customers) expence!

[PrincessBandit]

Yer, they are replacing our one. Its 80 years old, 470 meters long, carries heaps of traffic, but has no weight or speed restrictions on it..


Yeah the amount of traffic on that bridge is phenomenal at times and a replacement 2 lane is loooooooong overdue. I even hated traveling over it when I was a kid living in Thames, and recently when Balu and I trekked down to Matatoki on the bikes there was a huuuuuuge black humpy thing right in the middle of the lane as you approach the Thames end exit. However that is one bridge where traffic volume alone makes 2 lanes essential. I can't speak for other examples down in the quiet south....:dodge:

[Okey Dokey]

ALERT!!! These bridges are currently CLOSED due to damage from recent high water levels in the Waitaki river. They are not likely to reopen until the middle of next week. Pedestrians only are allowed to cross between 6am and 10 pm. If you are coming over the Haka Pass your nearest fuel is now in Glenavy or Waimate, approximately 71 km away.

[oldrider]

ALERT!!! These bridges are currently CLOSED due to damage from recent high water levels in the Waitaki river. They are not likely to reopen until the middle of next week. Pedestrians only are allowed to cross between 6am and 10 pm. If you are coming over the Haka Pass your nearest fuel is now in Glenavy or Waimate, approximately 71 km away.

Bloody big inconvenience that should have been attended to years ago! :spanking:

They couldn't find solid foundation to build Aqua on, I hope they can find some for the bridge! :shit:

That's the problem they are facing with the current "old" bridges, the piles (foundations) are failing! :facepalm:

Long way for you to go for an ice-cream now Okey Dokey! :rolleyes:

[Gone Burger]

The local council have been planning on replacing the second of the 4 single laned bridges on the Akatarawa Road for some time now. Finally, they are making a start on it. My house is past the bridge as is currently on the market. I am desperate for a sale. But up until now the council had planned on NOT putting in a Baily bridge for the local residents, work taking up to 10 weeks, and putting a single landed bridge back in.

BUT... they has just released the news that a Baily bridge will be in place, and a duel landed bridge is a go. Fan-fricken-tastic. I no longer live in the house, ex partner does. Before if anyone was considering putting in an offer (and someone was), they would have instantly withdrawn it with the knowledge that there would be no access from that end of the road to the house for up to 10 weeks.

Thankfully, that is not a worry I do not have. Didn't sleep for a month trying to figure out my legal position on info I told my land agent, rights with council etc... Phew! Has sale can continue (ever so slowly!!!) and the residents will benefit greatly for having a safe new bridge that no longer has such a great weight restriction in place. That was the second best news I could have received, except for hearing of an offer on the house. Poo - maybe that will come next?

[Okey Dokey]

Long way for you to go for an ice-cream now Okey Dokey! :rolleyes:

Yes, every cloud has a silver lining. A long bike ride + an ice cream = happiness! :)