Documents / Document
This is the final highway accident report (NTSB-HAR-71-1) from the National Transportation Safety Board, adopted in December 1970. It covers the collapse of the U.S. 35 bridge between Point Pleasant, West Virginia, and Kanauga, Ohio, on December 15, 1967, which killed 46 people. The Board found that the cause was a cleavage fracture in eyebar 330 at joint C13N. That fracture grew from a flaw produced over 40 years by stress corrosion and corrosion fatigue, in a spot that could not be seen or found by inspection.
“R.G.”1 page
Read from the scan by GLM-OCR; expect the odd misread word.
The specifications further provided for quality control requirements for the type of steel stipulated. It provided that the computation of stresses could be performed on the assumption that the structure was linearly elastic, and stipulated the combinations of dead load, live load, dynamic and other forces which were to be considered in the design. Prior to the issue of the AASHO Specification of 1923, highway bridge designers were more or less dependent on their own judgment in matters which were later codified in the specifications. Some well recognized guides existed in related fields such as the specifications for the design for steel buildings by the American Institute of Steel Construction which was first issued in 1923, and the specifications for Steel Railway Bridges first issued by the American Railway Engineering Association in 1910. 2. The element of judgment was especially important for the designers of long span bridges, since none of the existing codes or specifications were intended to be applicable to such structures. As a matter of fact, no nationally recognized code for the design of long span bridges exists even today. There are three considerations that place the design of long span bridge structures in a special class: (a) The refinement with which the stress analysis is performed is of great importance since these structures often may not conform very well to the assumption that they are linear and elastic in their response. (b) The probability of obtaining maximum live load over the full length of the structure is remote compared to the probability of a similar situation on a shorter span. (c) The proportion of the total stress in the main supporting members, such as the cables or eyebar chain of a suspension bridge, due to the weight of the structure itself is much greater than it is for short span structures, frequently accounting for 70-90 percent of the total load in such members. The first of these special considerations requires that stress computations for long span structures be carried out with greater care and that the indicated results from the assumptions of linear elastic behavior be carefully examined for their validity and revised, if necessary, by more refined methods which take into account the effects of distortion in the structure upon its internal equilibrium. In the case of the Point Pleasant Bridge Design, the stress analysis was
Document, cited by the archive. The PDF is mirrored here; the original link is above. The text was read from the page images by GLM-OCR; expect the odd misread word. 202 pages are in the text index: search them above, or from the library's search.