JTRP Technical Reports

Final report.PDFTech ReportFHWA/IN/JTRP-2012/12SPR-3474Environmental impactsFiresSteel bridgesGirdersLoad testsFatigue (Mechanics)IndianaPurdue University. Joint Transportation Research ProgramConnor, Robert J.Varma, Amit H.Marcu, SorinSherman, Ryan J.Purdue University. Joint Transportation Research ProgramIndiana. Dept. of TransportationUnited States. Federal Highway AdministrationNTL-ENERGY AND ENVIRONMENT-Environment ImpactsNTL-HIGHWAY/ROAD TRANSPORTATION-Bridges and StructuresUS Transportation CollectionOn October 22, 2009, in Indianapolis, Indiana, a semi tanker carrying liquefied propane lost control on the underpass from I\ue2\u20ac?69southbound to I\ue2\u20ac?465 eastbound, crashing beneath the east and westbound bridges carrying mainline I\ue2\u20ac?465 traffic. The tanker rolled,causing the tractor to catch fire and the propane tanker to explode. There were concerns the steel superstructure and the high\ue2\u20ac?strength(HS) bolts used in the beam splices were affected by the fire. Also, since the bridge deck was built composite with the steelsuperstructure, there were concerns the composite action might have been lost or diminished causing the bridge to not behave as it wasoriginally designed. Therefore, the study was focused on identifying any short\ue2\u20ac?term or long\ue2\u20ac?term effects the bridge may have sustaineddue to the fire exposure. To address the short\ue2\u20ac?term effects, immediately after the accident, several core samples and HS bolts wereremoved and sent to independent testing laboratories. To establish any long\ue2\u20ac?term effects, field testing was performed over a period ofapproximately four (4) months. Weldable resistance strain gages were installed at key locations to understand the behavior of thebridge under load and to develop the stress\ue2\u20ac?range histograms. Both controlled load tests, using test trucks of known weight andgeometry, and long-term monitoring of random traffic were performed as part of the study.The results presented in this report show the following: The explosion and subsequent fire did not negatively impact the properties of the steel in the main girders, nor the propertiesof the HS bolts; The explosion and subsequent fire did not negatively impact the overall load distribution nor adversely alter the behavior ofthe bridge; Controlled load testing and long\ue2\u20ac?term monitoring confirmed the steel girders are acting compositely with the concrete deck; Based on the results of the long\ue2\u20ac?term monitoring, infinite fatigue life is expected at all the monitored locations