New Pedestrian Bridge Engineering

[digbeth]

As you might have seen and the news and in person as you went past the Suk/Klang underpass this past couple of days, there's a new pedestrian bridge being installed.

I'm surprised the usual comments from the naysayers aren't heard yet.  It's going to fall down!

 

As it's a very challenging engineering, the bridge's whole span run across all the lanes of Sukhumvit with no support in the middle. 

You can get large span with post tensioned concrete and it's pretty common in Thai building these days, but this bridge is steel girders, if the beams used is the whole length of the bridge I'd say that's pretty sound, but looks like this bridge is being welded together on site from smaller sections, okay I guess you can bolt and weld together sections of girders  but I'd expect some cable suspended design instead.

 

Not saying it's gonna collapse like the one guy said about Central's cracked pillar, but surprised that there aren't any armchair engineer coming out of the woodwork to bash this project like the tunnel itself yet.

[Enoon]

 

Thanks for sharing your "surprise".

 

It was fascinating.

 

Has anyone else been surprised recently?

 

 

Edited September 6, 2018 by Enoon

[newnative]

     Bridges thought to be engineered properly can fail anywhere in the World; Italy and Florida being two recent examples.  The Florida bridge was brand new.   I'm surprised this pedestrian bridge won't have a center support, if what you say is correct.  Seems an awfully wide expanse not to be supported.  If that's the case, I'll be crossing my fingers every time we drive under it.  Not because it's Thailand but because bridges thought to be engineered properly can fail anywhere in the World.  

[lapd]

At least the naysayers have stopped with their "the tunnel is going to flood" whining, for now.  Heaven forbid a puddle forms in the tunnel.  We will never hear the end of it.

Edited September 7, 2018 by lapd

[lapd]

What sucks is that they are apparently going to take out the existing pedestrian overpass at Klang even though they recently fixed it up and added a roof.  Nobody is going to walk halfway to Pattaya Nua to take the new crossing so now you have to take your chances crossing sukhumvit at the lights.  

Edited September 7, 2018 by lapd

[DrTuner]

The same kind as the one with the sawasdee or yindeetoonrap text or whatever that is/used to be over suk? It's a concrete slab as far as I can see, not really an engineering marvel. Lucky there aren't earthquakes around here.

[johng]

8 hours ago, digbeth said:

Not saying it's gonna collapse like the one guy said about Central's cracked pillar, but surprised that there aren't any armchair engineer coming out of the woodwork to bash this project like the tunnel itself yet. 

There wasn't just one pillar that had to be reinforced,in fact I don't think the pillars where the problem

it was the bond between pillar and concrete slab.

[Kaoboi Bebobp]

Since I'm away at the moment, a photo of this (dodgy?) pedestrian bridge would be nice. I've walked across the current bridge several times. That was brand new a year or two ago. So where is this "newer" bridge?

[eyecatcher]

Theres a couple or three pedestrian bridges In Chiang Mai I have crossed. All over water.

I looked at the rsj framework on one and tbh I gave it a surprisingly thumbs up, for being well made and robust.

 

It was the finishing that let it down. The deck was made from 15mm sherawood boards and about 1 in 3 boards already busted. The access and egress points were not even anchored down.

 

you will no doubt read about the tourists swept away in mega bridge collapse in 6 months time.

[digbeth]

 

This is the bridge with lifts for wheelchairs in front of Father Ray. The one that the pawn shop on the other side opposed for so long that it held up the opening of the underpass.

 

The white sections are the bridge before they were welded together, it span across the whole road unsupported, It was lifted into place last night,

 

Edited September 7, 2018 by digbeth

[digbeth]

12 hours ago, lapd said:

What sucks is that they are apparently going to take out the existing pedestrian overpass at Klang even though they recently fixed it up and added a roof.  Nobody is going to walk halfway to Pattaya Nua to take the new crossing so now you have to take your chances crossing sukhumvit at the lights.  

What makes you think they're gonna take out the one at Klang, this new bridge is an addition especially for Father Ray's students with wheelchair needs.

[digbeth]

12 hours ago, newnative said:

     Bridges thought to be engineered properly can fail anywhere in the World; Italy and Florida being two recent examples.  The Florida bridge was brand new.   I'm surprised this pedestrian bridge won't have a center support, if what you say is correct.  Seems an awfully wide expanse not to be supported.  If that's the case, I'll be crossing my fingers every time we drive under it.  Not because it's Thailand but because bridges thought to be engineered properly can fail anywhere in the World.  

The width across Sukhumvit there is about 50 meters, just about the same as the Florida's pedestrian bridge that collapsed. But the Florida's bridge was post tensioned concrete where it should have been suspended instead.

 

This bridge over Sukhumvit is steel box girder/truss which is pretty well understood, but the length means for transport it was not constructed from a continuous beam but in shorter sections that's welded or bolted together on site. How much finger crossing should you do when passing under it depends on how much credit you give to Thai laborer who welded it into place.

[newnative]

46 minutes ago, digbeth said:

The width across Sukhumvit there is about 50 meters, just about the same as the Florida's pedestrian bridge that collapsed. But the Florida's bridge was post tensioned concrete where it should have been suspended instead.

 

This bridge over Sukhumvit is steel box girder/truss which is pretty well understood, but the length means for transport it was not constructed from a continuous beam but in shorter sections that's welded or bolted together on site. How much finger crossing should you do when passing under it depends on how much credit you give to Thai laborer who welded it into place.

     So, welds or bolts.  I think both were involved in the  deadly collapse of the walkways at the Hyatt Hotel in Kansas City years ago.   Hopefully some lessons were learned but fingers still crossed.  

[eyecatcher]

It appears from the above photo, that the wheelchair access tower has only been built on the left side.

 

Well I suppose they can scuttle across and then come straight back unless they wanna try the stairs.

[lapd]

On 9/7/2018 at 8:39 AM, digbeth said:

What makes you think they're gonna take out the one at Klang

 

The news story on this board that said they were going to do that.

Edited September 8, 2018 by lapd

[morrobay]

Whatever you can question about the engineering it is by far safer than a traffic light crossing. Now they need about 20 of these bridges in Pattaya.The Tai,klang,nua.beach rd and 2nd

[lapd]

2 hours ago, morrobay said:

Whatever you can question about the engineering it is by far safer than a traffic light crossing. Now they need about 20 of these bridges in Pattaya.The Tai,klang,nua.beach rd and 2nd

Then we would have 20 threads whining about how Thais can't do anything right and they are all going to fall/flood/whatever.  I honestly don't know why people would decide to move to a country and then spend so much time complaining about it.  I guess a lot of them end up joining the Pattaya diving club.

Edited September 9, 2018 by lapd

[KhunBENQ]

On my checklist for next week: take a picture!

50 m span for a pedestrian bridge does not sound like rocket science.

494 m suspension bridge in the Swiss alps spanning over a valley for those free from giddiness

Edited September 9, 2018 by KhunBENQ

[oldrunner]

Please wait until this overpass is completed before "engineering geniuses" critique it. Trust me, if there is "Wheelchair" access on one tower, there will be one on the other. As a wheelchair user I would like to apologize for the inconvenience I may cause to those of you who can "Jump" out of the way as my driver speeds down shopping aisles.

[Gandtee]

On 9/7/2018 at 4:46 AM, Enoon said:

 

Thanks for sharing your "surprise".

 

It was fascinating.

 

Has anyone else been surprised recently?

 

 

I'm surprised that anyone can be surprised in Thailand. It's full of surprises.

[andygrr]

4 hours ago, morrobay said:

Whatever you can question about the engineering it is by far safer than a traffic light crossing. Now they need about 20 of these bridges in Pattaya.The Tai,klang,nua.beach rd and 2nd

 Not many people use the ones that are there.  I see people trying to cross the road all the time not 30m away from the walkways sometimes they cross right under them. Never seen anyone using the one near the Ambassador hotel they just run the gauntlet. 

[janclaes47]

On 9/7/2018 at 10:47 PM, digbeth said:

The width across Sukhumvit there is about 50 meters, just about the same as the Florida's pedestrian bridge that collapsed. But the Florida's bridge was post tensioned concrete where it should have been suspended instead.

But didn't you just say in your OP

 

On 9/7/2018 at 3:57 AM, digbeth said:

You can get large span with post tensioned concrete and it's pretty common in Thai building these days

 

[johng]

8 minutes ago, andygrr said:

Never seen anyone using the one near the Ambassador hotel they just run the gauntlet. 

A lot less run the gauntlet now  they painted over the (dangerous) zebra crossing  put up signs to use the bridge and half closed the U-turn

Though some still cross

[KhunBENQ]

19 minutes ago, johng said:

Though some still cross

Until the next "Russian tourist overrun".

The last I remember in the forum is a couple of months ago.

[morrobay]

51 minutes ago, andygrr said:

 Not many people use the ones that are there.  I see people trying to cross the road all the time not 30m away from the walkways sometimes they cross right under them. Never seen anyone using the one near the Ambassador hotel they just run the gauntlet. 

That's because Thais are oblivious / clueless regarding safely crossing a busy street So build these 20 more overpasses for the foreigners in Pattaya and another 5 for Naklua. 

Edited September 9, 2018 by morrobay

[johng]

8 minutes ago, KhunBENQ said:

Until the next "Russian tourist overrun".

The last I remember in the forum is a couple of months ago.

Yes  March 8th 2018   R.I.P  Sergei Paialnikov

[Sprigger]

Whilst we’re on the subject of bridges forget the Suk. What’s needed here is at least 10 the length of Beach Rd. same over 2nd Rd. and several across 3rd Road. What a financial project for the authorities to get their sticky little fingers in.

[dallen52]

On 9/7/2018 at 4:46 AM, Enoon said:

 

Thanks for sharing your "surprise".

 

It was fascinating.

 

Has anyone else been surprised recently?

 

 

I think I mentioned previously. 

They put the top section in place and build the steps down...

As an engineer it is interesting. 

 

Not exactly fascinating. 

But interesting, to the point where it probably falls down... ?

 

Normally ending up with a 12 inches high slab of concrete as the first step. 

It also hide the shortfalls in calculations..

[dallen52]

7 minutes ago, Sprigger said:

Whilst we’re on the subject of bridges forget the Suk. What’s needed here is at least 10 the length of Beach Rd. same over 2nd Rd. and several across 3rd Road. What a financial project for the authorities to get their sticky little fingers in.

But we have millions of bahts worth of pedestrian crossings now.

 

Just need to educate people about what red means...

[Suradit69]

On 9/7/2018 at 10:22 AM, newnative said:

     Bridges thought to be engineered properly can fail anywhere in the World; Italy and Florida being two recent examples.  The Florida bridge was brand new.   I'm surprised this pedestrian bridge won't have a center support, if what you say is correct.  Seems an awfully wide expanse not to be supported.  If that's the case, I'll be crossing my fingers every time we drive under it.  Not because it's Thailand but because bridges thought to be engineered properly can fail anywhere in the World.  

Yes, the fanous song was not written about bridges in Pattaya.

 

Quote

 

London Bridge is falling down
Falling down, falling down
London Bridge is falling down 
My fair lady

Build it up with iron bars
Iron bars, iron bars
Build it up with iron bars
My fair lady

Iron bars will bend and break
Bend and break, bend and break
Iron bars will bend and break
My fair lady

 

etc