×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Bridge collapse near Pittsburg, PA

Bridge collapse near Pittsburg, PA

Bridge collapse near Pittsburg, PA

(OP)
Below are a few articles with photos of a bridge collapse near Pittsburg, PA.  The bridge is an adjacent concrete box beam bridge carrying a local road over I-70.  From the photos it looks like one of the fascia beams carrying the railing failed at midspan and collapsed.  Luckily, the beam collapse happened during a break in traffic on I-70 and no one was seriously injured.  

Anyone have additional info?? Thoughts on possible causes of collapse??

http://www.post-gazette.com/pg/05362/628813.stm

http://www.pittsburghlive.com/x/tribune-review/trib/regional/s_408139.html

http://www.observer-reporter.com/main.asp?SectionID=6&SubSectionID=15&ArticleID=7700

RE: Bridge collapse near Pittsburg, PA

There  are two possible scenarios for this collapse. One will be a direct hit by an oversized truck (rather unlikely- it would happen already) and the other, more likely, corrosion of the prestressing wires.  

RE: Bridge collapse near Pittsburg, PA

A couple of things come to mind.

1.  The admission this bridge was rate as structurally deficient.
2.  Where are the typical tension rods (to hold them together) that accompany precast deck beams?
3.  If it was corrosion of the prestressing strands then at one time they were likely exposed from spalling concrete and patched...seems like someone should have seen this coming.

Terrible tragedy since it shouldn't have happened.

Regards,
Qshake

Eng-Tips Forums:Real Solutions for Real Problems Really Quick.

RE: Bridge collapse near Pittsburg, PA

Probably not the cause of the collapse, but it seems like the bridge has a fairly high skew as well.

RE: Bridge collapse near Pittsburg, PA

Critical components for this collapse, from what I have gleaned from news:

1.  It was non-composite.  No alternate load path for the failed beam.

2.  The deck drainage was infiltrating the beams through the asphalt wearing course.  Voids in the box contained water!

3.  Low vertical clearance led to vehicular impacts.

4.  It was, as I understand, a locally-owned rather than a state-owned bridge.  Perhaps the inspections were less than they could have been.

Lessons:

Follow basic design rules, i.e. watch where the water is going, provide redundancy, inspect and maintain.

Transverse tensioning rods were either corroded or inadequate to prevent collapse.

"Do not lay up for yourselves treasures on earth, where moth and rust ..."  Matt. 6:19


RE: Bridge collapse near Pittsburg, PA

Certainly the bridge failed in resisting bending and shear at the critical sections(edge for shear). Maintenance authority is responsible for lack of management of bridges, however the aspects of falling concrete and rebar corrosion on the adjacent carriage way have been noticed earlier according to the sources.

YUF
Bridge Engineer.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources