sobo Posted January 18, 2008 Share Posted January 18, 2008 From today's ASCE newsletter: NTSB Says Design Flaw Found in I-35W Bridge The National Transportation Safety Board (NTSB) today announced that a serious design flaw was found in some of the gusset plates on the I-35W bridge in Minneapolis, which collapsed on Aug. 1, 2007. As a result, the NTSB issued a recommendation that the Federal Highway Administration (FHwA) require bridge owners to verify that the stress levels in all structural elements, including gusset plates, remain within applicable requirements whenever planned modifications or operational changes may significantly increase stresses. This would apply to all non-load-path-redundant steel truss bridges within the National Bridge Inventory. ASCE will continue to monitor the NTSB’s investigation and will incorporate the recommendations and lessons learned into our future technical and professional policies and standards. For enginurds and those with a similar interest in this catastophic failure, there are links to the NTSB Safety Recommendation Letter and the FHWA Interim Report at the bottom of the NTSB press release. Quote Link to comment Share on other sites More sharing options...
RuMR Posted January 18, 2008 Share Posted January 18, 2008 yeah...we've been chewing on this one in the office... Quote Link to comment Share on other sites More sharing options...
sobo Posted January 18, 2008 Author Share Posted January 18, 2008 Yeah, Rudy, I'll bet you have... Quote Link to comment Share on other sites More sharing options...
RuMR Posted January 18, 2008 Share Posted January 18, 2008 well...WSDOT loadrates bridges for MAIN MEMBERS only currently...not connections...so, when it issues a load limit or an overload permit, it covers only the main members... Philosophy in design is that the connection should be able to develop the member, not the load transmitted to it. So the above policy is sound in the sense that the members are a "load fuse". Of course, this assumes that the connection was designed properly. Quote Link to comment Share on other sites More sharing options...
sobo Posted January 18, 2008 Author Share Posted January 18, 2008 I wasn't being sarcastic or anything when I said ^^, just that I really believe you guys are watching this one pretty closely. So do you think this will cause a change in WSDOT's thinking about what elements get modeled/looked at for load ratings/limits and/or overload permits? Quote Link to comment Share on other sites More sharing options...
RuMR Posted January 18, 2008 Share Posted January 18, 2008 I know you weren't being sarcastic. honestly, it might. But i don't think it should. The whole point is that the bridge should be designed properly in the first place, in which case the current load ratings and permitting policies are appropriate...if you have a design flaw, well, then its fokked and should be identified and fixed via some other mechanism. The real bummer is that this will take some heat off of the government to start fixing its infrastructure now before we really do have a big problem to deal with... Quote Link to comment Share on other sites More sharing options...
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