Event Website

http://www.pooledfund.org/Details/Study/482

Session Number

72

Event Description/Abstract

Mechanically fastened built-up steel members have long been known to possess internal member redundancy and, as a result, multiple load paths which can be exploited to increase their functional life. Internal redundancy provides the ability to resist total member failure in the event of a fracture of an individual component. However, there is little experimental data in the literature regarding post-fracture capacity in terms of strength and subsequent fatigue life. The experimental study currently underway will provide needed information on parameters that affect the ability of built- up members to arrest a fracture as well as the available remaining fatigue life. Additionally, further information concerning load redistribution and energy release during a fracture is being studied. Test specimens consist of both existing riveted and new high-strength bolted large-scale built-up plate girders.

The results from this study will be used to develop recommended design and assessment procedures for both types of members in the as-fractured condition. The potential exists to remove the fracture critical classification from existing and new bridges in which built-up members are utilized. In cases where sufficient capacity exists and the fracture critical designation can be removed, rational in- service inspection procedures will also be developed.

This presentation will report on the research results obtained to date. Considering the large number of riveted fracture critical bridges in the inventory, many agencies will benefit through implementation of more rational based inspection frequencies resulting from this study. Further, new members utilizing high-strength bolted built-up members could also be used without the penalty of being classified as fracture critical in terms of inspection.

46-3 Fracture Trimmed.mp4 (2091 kB)
Fracture Video - 46" Specimen: Member-level redundancy of built-up steel girder

Canon Trimmed.mp4 (4285 kB)
Fracture Video - 46" Specimen: Member-level redundancy of built-up steel girder

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Mar 12th, 12:00 AM

Post-failure Capacity of Built-up Steel Members

Mechanically fastened built-up steel members have long been known to possess internal member redundancy and, as a result, multiple load paths which can be exploited to increase their functional life. Internal redundancy provides the ability to resist total member failure in the event of a fracture of an individual component. However, there is little experimental data in the literature regarding post-fracture capacity in terms of strength and subsequent fatigue life. The experimental study currently underway will provide needed information on parameters that affect the ability of built- up members to arrest a fracture as well as the available remaining fatigue life. Additionally, further information concerning load redistribution and energy release during a fracture is being studied. Test specimens consist of both existing riveted and new high-strength bolted large-scale built-up plate girders.

The results from this study will be used to develop recommended design and assessment procedures for both types of members in the as-fractured condition. The potential exists to remove the fracture critical classification from existing and new bridges in which built-up members are utilized. In cases where sufficient capacity exists and the fracture critical designation can be removed, rational in- service inspection procedures will also be developed.

This presentation will report on the research results obtained to date. Considering the large number of riveted fracture critical bridges in the inventory, many agencies will benefit through implementation of more rational based inspection frequencies resulting from this study. Further, new members utilizing high-strength bolted built-up members could also be used without the penalty of being classified as fracture critical in terms of inspection.

http://docs.lib.purdue.edu/roadschool/2014/presentations/62