Evaluation and testing of a fracture critical bridge

• Published in: NDT & E international : independent nondestructive testing and evaluation Vol. 28; no. 6; pp. 339 - 347
• Main Authors: Idriss, R.L., White, K.R., Woodward, C.B., Jauregui, D.V.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.12.1995; Elsevier Science
• Subjects: Applied sciences; Bridges; Buildings. Public works; Exact sciences and technology; fracture; Measurements. Technique of testing; Metal bridges; redundancy; bridges; redundancy; fracture; Metallic structure; Resistance strain gauge; Bridges; Load distribution; Fracture mechanics; Engineering work; Redundancy; Test method; Static test; Monitoring; Structural analysis
• ISSN: 0963-8695; 1879-1174
• DOI: 10.1016/0963-8695(95)00044-5

The I-40 bridges over the Rio Grande in Albuquerque, New Mexico were due to be razed in the fall of 1993 due to geometry and traffic safety considerations, thus providing a unique opportunity for testing them. These medium span steel bridges represent a common design in the US and are classified by AASHTO as non-redundant ‘fracture critical’ two girder steel bridges (fracture critical classification means that failure of a primary member would probably cause collapse of the bridge). The subject bridge, built in 1963, is a 1275 foot (600m) bridge, and consists of three medium span continuous units with spans of 131′-163'−131′ each. The bridge was field tested to determine the impact of a near full depth girder fracture on the redistribution of loads, the load capacity, and the potential for collapse. Four levels of damage were introduced in the middle span of the north plate girder by making various cuts in the web and the flange of the girder. The final cut resulted in a six foot deep crack in the 10ft deep girder, extending from the bottom flange to the floor beam to girder connection. Data was taken under dead load and under a static live load consisting of an 82 000 lb truck. The after fracture response and the load redistribution in the fractured bridge were evaluated. The contribution of the different members to the redundancy of the structure was assessed.