Another Minn Bridge with problem gussets

[JAE]

MN DOT finds some bent gussets in another similar bridge to the I35W bridge that collapsed. I guess we can say that the inspectors are a bit more focused after that collapse.

http://enr.construction.com/news/transportation/archives/080321b.asp

 

[civeng80]

Amazing how peoples perception of safety changes after a structural collapse of a major structure.

 

[Robertmet]

The photos [2003 ]of the I35W bridge gussets have been released.A no brainer !!!

http://www.msnbc.msn.com/id/23769128

 

[unclesyd]

Something isn't clear about the gusset plates where they too thin as designed/built or where they too thin at the time of failure due to additional weight imposed by later modifications.

 

[bridgebuster]

The question we need to ask: Was the bending due to some abnormal movement of the bridge or was did it occur during construction?

If you've ever worked with ironworkers things get bent all the time.

 

[prost]

Who can tell for certain if they were too thin or not? Weren't the design documents 'lost'?

Speaking of the design documents, what is the typical requirement for saving and storing design docs after the structure is built? Aviation keeps these things forever because of maintenance requirements. What about non aviation structures?

 

[CJJS]

I believe there was a report stating that the gussets were underdesigned (based on recalculation). You don't really need the original documents to determine that.

 

[csd72]

I love how they quote lawyers as if they are expert witnesses.

 

[concretemasonry]

I heard this brodge may have been designed bu the same firm that did the I35W bridge.

 

[unclesyd]

In the photo referenced in the post by Robertmet what would the approach to fix it if someone deemed it had to fixed PDQ?

 

[Qshake]

Unclesyd - bolting stiffener angles is not uncommon to the retrofit of gusset plates.

Prost - I believe the industry standard is 7-10 years for keeping calculations and other documentation. This bridge and the 35 bridge are well over 40 yrs old. And as I understand it, the firm was acquired by another larger firm...when that happens there is a typical house cleaning. Hence I don't think it unusual to expect to find original calculations.

Regards,
Qshake

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