NTSB makes safety recommendations to AASHTO.
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Press Release Summary:
According to NTSB, AASHTO should work with FHA to develop and implement bridge design quality assurance/quality control program to detect and correct bridge design errors before plans are final. Manual for Bridge Evaluation should include guidance for conducting load ratings on new bridges before they are placed in service, as well as evaluating capacity of gusset plates as part of load rating calculations performed for non-load-path-redundant steel truss bridges.
Original Press Release:
NTSB Safety Recommendations H-08-20 through -25
The National Transportation Safety Board makes the following recommendations to the American Association of State Highway and Transportation Officials:
Work with the Federal Highway Administration to develop and implement a bridge design quality assurance/quality control program, to be used by the States and other bridge owners, that includes procedures to detect and correct bridge design errors before the design plans are made final; and, at a minimum, provides a means for verifying that the appropriate design calculations have been performed, that the calculations are accurate, and that the specifications for the load-carrying members are adequate with regard to the expected service loads of the structure. (H-08-20)
Revise your Manual for Bridge Evaluation to include guidance for conducting load ratings on new bridges before they are placed in service. (H-08-21)
Modify the guidance and procedures in your Manual for Bridge Evaluation to include evaluating the capacity of gusset plates as part of the load rating calculations performed for non-load-path-redundant steel truss bridges. (H-08-22)
When the findings of the Federal Highway Administration-American Association of State Highway and Transportation Officials joint study on gusset plates become available, update the Manual for Bridge Evaluation accordingly. (H-08-23)
Develop specifications and guidelines for use by bridge owners to ensure that construction loads and stockpiled raw materials placed on a structure during construction or maintenance projects do not overload the structural members or their connections. (H-08-24)
Include gusset plates as a commonly recognized structural element (CoRe) and develop guidance for bridge owners in tracking and responding to potentially damaging conditions in gusset plates, such as corrosion and distortion; and revise the AASHTO Guide for Commonly Recognized (CoRe) Structural Elements to incorporate this new information. (H-08-25)
http://ntsb.gov/recs/letters/2008/H08_20_25.pdf
The complete recommendation letter is available on the Web at the URL indicated above.
The letter is in the Portable Document Format (PDF) and can be read using the Acrobat Reader 5.0 or later from Adobe (http://www.adobe.com/prodindex/acrobat/readstep.html).
