The bridge.

[Summitric]

This is sooooooo 2013 Ric But a good try.....

the bridge beams were built 2013... heehehehehe

 

[Summiteer]

I see the first 2 are completely cross braced. Is it possible that in an effort to save time they decided not to cross brace as each girder was placed, and sitting unsupported for too long they folded?

 

[luvz da mud]

The weight of the girders will be transferred to the crane so that workers can inspect the steel beams, and begin repairing or removing them.

Just bend them back? If that's the city's thinking it's no wounder they failed in the first place

 

[maxwell]

Just bend them back? If that's the city's thinking it's no wounder they failed in the first place

lol yea that does sound bad. there is a certain amount of flex they can handle without damaging them but "straighten them out and call it good" wont sit well with the citizens

 

[Riverjet]

Who are the contractors on this job?

 

[maxwell]

Graham

 

[MACHINE]

Those beams should of been chuck norris approuved lol

 

[gates559]

Caused by stupidity, You see China had a high demand for our metal so We sent them our junk cars and pop cans. and then they recycled the cars back into metal and sold the chit metal back to us, resulting in these faulty beams. We should not give our resources away and pay more to get them back as an inferior product.

I could be off, it may have also been caused by someone saving a few bucks and making more profit. Perhaps inexperienced workers or inferior product.

Also could have been a "conspiracy" designed to fail to help stimulate the economy, provide jobs during the recession.

 

[arff]

Well I have about 7 broken Polaris axles from the last 5 year's and a can of glue.


I will go fix the bridge tomorrow.


It will be lighter...

 

[woody_tobius_jr]

truckers!!!!



turned corner to sharp

Easy now, we were the ones hauling the bridge beams to site, how do you expect something that long to stay straight going down Groat Road.??....
Maxwell has the best explanation so far. Wind wasn't the issue.


Sent from my iPad

 

[52weekbreak]

Contractor allowed only a very limited time to close Groat Road so time counts. They have to set the beams in place and provide some cross bracing and begin next lift. Other crews are following installing cross bracing which takes longer than the lift and placement. Bracing falls behind but due to time limitations, the lift goes on.

An unforecast microburst apparently hit very late Sunday night and the combination of wind load and lack of cross bracing caused the flex. Once the bend started, the weight of the girders carried over further.

Not quite as sciency as T-Team and not as in depth as Maxwell but that is what apparently happened. The engineers should have an official report within the week. I guess we'll see then.

Graham does lots of bridges but you don't see too many with this deep an I beam. They look to be about 8 feet tall and the top and bottom flanges are only about 16 inches wide.

 

[Cat401]

contractor is paying city of Edmonton 15k per day....for every day groat road is closed....ouch

 

[maxwell]

yup. a few project managers wont be sleeping very good for the next few weeks

 

[imdoo'n]

were t-team and Maxwell working on this bridge? that would explain a bunch! lol

 

[imdoo'n]

were t-team and Maxwell working on this bridge? that would explain a bunch! lol

too much DOO juice at break time!

 

[sledneck_03]

how so?

Girder installations are serious business and supreme is the best at it. ( girder supply and erection is typically a one contract item). from the limited details i have and a few photos my conclusion is as follows. This bridge is a single span bridge with 3 girder sections. east west and centre. This means there are no piers for the girders to cantilever and the east and west sections must be temporarily supported past the centre of gravity and chained down at the abutment ends. followed by complete cross brace installation on those completed sections before the centre girders are installed and cross braced. the girders that twisted are in the center section. Steel girders are extremely flimsy in torsion and are designed for only downward force. only when the entire girder structure is cross braced and the concrete deck is cast onto the girders does it become full strength in torsion (earthquake), side load (wind) and down force (vehcles). as girders are installed a team follows quickly behind and installs cross bracing but does not torque all bolts until complete. my "guess" is that the weight of the centre girder sections installed combined with warmer temperatures caused the temporary shoring to sink. This could even be by as little as 20mm to cause this. from the photos you can see the cross bracing team was not able to completely cross brace the damaged section before this occurred. if the shoring did in fact sink this would put extreme amounts of compression on top of the girder and tension on the bottom of the girder causing it to buckle. had they been able to fully cross brace the centre in time this likely would not have happened but it still could have due to the amount of force. In my opinion this is not a matter of poor quality steel ( this is checked and double checked before fabrication and shipping). it is also in my opinion not a fault of the installation crew but more an oversight into the temporary shoring systems in place. i would like to think i am wrong and it was something else because typically all things are considered such as temperature while the contractor and engineer are developing and approving a girder erection plan. I also have a hard time thinking this is a design flaw in the girders for 2 reasons. #1 the girders sitting with no concrete deck or traffic have less than 20% of their design load on them and i dont think they could have fawked that up that bad. #2 the computer software used to design girders is mind blowing. they run them through dynamic and static load tests, wind, earthquake etcetc tests before they are fabricated.

Just my 2c

torsional buckling, should have been braced like the ones on the left prior to disconnecting the cranes.

 

[maxwell]

torsional buckling, should have been braced like the ones on the left prior to disconnecting the cranes.

Sure but that's not the crane operators fault lol

 

[sledneck_03]

Sure but that's not the crane operators fault lol

depends. If there was a engineered lift drawing set that wasnt followed its the on site supervisors/project managers fault. if the engineered lift drawing set or stamped bridge drawing set didnt specify then its the engineering companies fault.

i do engineered lift drawing sets all the time. Lots of times the scope is just for lifting, so we attach lugs of swivel hoist rings and demonstrate how to lift it and where and loads the cranes will see but there will be a note unless it was in the scope for the owner to ensure structure is capable of withstanding loads stated in drawing set. Just because the lugs wont rip off doesnt mean it wont fold in half........

 

[pfi572]

Why doesn't Graham or the engineers join S&M and get this chit figgered out??
Lol
They could just pm maxi pad and problem solved .
Jeesh

 

[intmid8or!]

or become site sponsor and have this thread pulled