Details
| Original language | English |
|---|---|
| Article number | 308 |
| Journal | Polymers |
| Volume | 8 |
| Issue number | 8 |
| Publication status | Published - 18 Aug 2016 |
| Externally published | Yes |
Abstract
Most research on fatigue strengthening of steel has focused on carbon fiber-reinforced polymer (CFRP) strengthening of steel members with existing cracks. However, in many practical cases, aging steel members do not yet have existing cracks but rather are nearing the end of their designed fatigue life. Therefore, there is a need to develop a "proactive" retrofit solution that can prevent fatigue crack initiation in aging bridge members. Such a proactive retrofit approach can be applied to bridge members that have been identified to be deficient, based on structural standards, to enhance their safety margins by extending the design service life. This paper explains a proactive retrofit design approach based on constant life diagram (CLD) methodology. The CLD approach is a method that can take into account the combined effect of alternating and mean stress magnitudes to predict the high-cycle fatigue life of a material. To validate the retrofit model, a series of new fatigue tests on steel I-beams retrofitted by the non-prestressed un-bonded CFRP plates have been conducted. Furthermore, this paper attempts to provide a better understanding of the behavior of un-bonded retrofit (UR) and bonded retrofit (BR) systems. Retrofitting the steel beams using the UR system took less than half of the time that was needed for strengthening with the BR system. The results show that the non-prestressed un-bonded ultra-high modulus (UHM) CFRP plates can be effective in preventing fatigue crack initiation in steel members.
Keywords
- Bonded, Carbon fiber-reinforced polymer, Constant life diagram, High-cycle fatigue life, Old steel members, Prevention of crack initiation, Rehabilitation, Riveted metallic bridges, Strengthening, Unbonded
ASJC Scopus subject areas
- Chemistry(all)
- Materials Science(all)
- Polymers and Plastics
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In: Polymers, Vol. 8, No. 8, 308, 18.08.2016.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - A retrofit theory to prevent fatigue crack initiation in aging riveted bridges using carbon fiber-reinforced polymer materials
AU - Ghafoori, Elyas
AU - Motavalli, Masoud
PY - 2016/8/18
Y1 - 2016/8/18
N2 - Most research on fatigue strengthening of steel has focused on carbon fiber-reinforced polymer (CFRP) strengthening of steel members with existing cracks. However, in many practical cases, aging steel members do not yet have existing cracks but rather are nearing the end of their designed fatigue life. Therefore, there is a need to develop a "proactive" retrofit solution that can prevent fatigue crack initiation in aging bridge members. Such a proactive retrofit approach can be applied to bridge members that have been identified to be deficient, based on structural standards, to enhance their safety margins by extending the design service life. This paper explains a proactive retrofit design approach based on constant life diagram (CLD) methodology. The CLD approach is a method that can take into account the combined effect of alternating and mean stress magnitudes to predict the high-cycle fatigue life of a material. To validate the retrofit model, a series of new fatigue tests on steel I-beams retrofitted by the non-prestressed un-bonded CFRP plates have been conducted. Furthermore, this paper attempts to provide a better understanding of the behavior of un-bonded retrofit (UR) and bonded retrofit (BR) systems. Retrofitting the steel beams using the UR system took less than half of the time that was needed for strengthening with the BR system. The results show that the non-prestressed un-bonded ultra-high modulus (UHM) CFRP plates can be effective in preventing fatigue crack initiation in steel members.
AB - Most research on fatigue strengthening of steel has focused on carbon fiber-reinforced polymer (CFRP) strengthening of steel members with existing cracks. However, in many practical cases, aging steel members do not yet have existing cracks but rather are nearing the end of their designed fatigue life. Therefore, there is a need to develop a "proactive" retrofit solution that can prevent fatigue crack initiation in aging bridge members. Such a proactive retrofit approach can be applied to bridge members that have been identified to be deficient, based on structural standards, to enhance their safety margins by extending the design service life. This paper explains a proactive retrofit design approach based on constant life diagram (CLD) methodology. The CLD approach is a method that can take into account the combined effect of alternating and mean stress magnitudes to predict the high-cycle fatigue life of a material. To validate the retrofit model, a series of new fatigue tests on steel I-beams retrofitted by the non-prestressed un-bonded CFRP plates have been conducted. Furthermore, this paper attempts to provide a better understanding of the behavior of un-bonded retrofit (UR) and bonded retrofit (BR) systems. Retrofitting the steel beams using the UR system took less than half of the time that was needed for strengthening with the BR system. The results show that the non-prestressed un-bonded ultra-high modulus (UHM) CFRP plates can be effective in preventing fatigue crack initiation in steel members.
KW - Bonded
KW - Carbon fiber-reinforced polymer
KW - Constant life diagram
KW - High-cycle fatigue life
KW - Old steel members
KW - Prevention of crack initiation
KW - Rehabilitation
KW - Riveted metallic bridges
KW - Strengthening
KW - Unbonded
UR - http://www.scopus.com/inward/record.url?scp=84983681080&partnerID=8YFLogxK
U2 - 10.3390/polym8080308
DO - 10.3390/polym8080308
M3 - Article
AN - SCOPUS:84983681080
VL - 8
JO - Polymers
JF - Polymers
SN - 2073-4360
IS - 8
M1 - 308
ER -