As the existing steel infrastructure inevitably continues to age and deteriorate, engineers are increasingly looking for innovative and effective methods for repairing and maintaining existing structures. Structural steel components can degrade due to the surrounding environmental conditions, and are susceptible to corrosion damage when exposed to aggressive environments and deicing salts. The conventional methods for repairing steel structures can be labor-intensive and time-consuming, and add considerable weight to the existing structure. One alternative is utilizing carbon fiber reinforced polymers (CFRP). Many studies have documented the ability of CFRPs to enhance the strength of existing structures. Furthermore, CFRP offers the benefits of being non-corrosive and having a high strength-to-weight ratio. Most studies on steel strengthening have focused on the bond behavior of CFRP to steels having a smooth surface condition, which are not representative of deteriorated structures in greater need of retrofitting. Further research has examined the durability of CFRP-steel bonds relative to environmental conditions that do not reflect the service life conditions for typical applications. In this work, a comprehensive study is conducted on the effects of the surface condition and environmental exposure on the bond between CFRP and steel. The influence of corrosion and simulated corrosion pitting is evaluated to determine whether structures with non-uniform surfaces are adequate for CFRP retrofits. In addition, the durability of CFRP-steel bonded systems is investigated through laboratory hygrothermal aging and in-situ environmental conditioning to multiple environments in Virginia. The research can be useful in the development of guidelines that will assist engineers determine if a CFRP retrofit solution is applicable in a given environmental setting and appropriate for the level of deterioration of the structure. / Doctor of Philosophy / As steel structures continue to age, engineers are looking for innovative and effective methods for repairing and maintaining the existing steel infrastructure. Steel components in structures can degrade due to the surrounding environmental conditions. The conventional methods for repairing steel structures can be labor-intensive and time-consuming, and add considerable weight to the existing structure. One alternative is utilizing carbon fiber reinforced polymers (CFRP). The ability of CFRPs to enhance the strength of existing structures has been widely documented. Furthermore, CFRP offers the benefits of being non-corrosive and avoids adding considerable weight to the structure. Most studies on steel strengthening have focused on the bond behavior of CFRP to steels having a smooth surface condition, which are not representative of deteriorated structures in greater need of retrofitting. Further research has examined the durability of CFRP-steel bonds relative to environmental conditions that do not reflect the service life conditions for typical applications. In this work, a comprehensive study is conducted on the effects of the surface condition and environmental exposure on the bond between CFRP and steel. The influence of corrosion and simulated corrosion pitting is evaluated to determine whether structures with non-uniform surfaces are adequate for CFRP retrofits. In addition, the durability of CFRP-steel bonds exposed to laboratory and field conditions is investigated. The research can be useful in the development of guidelines that will assist engineers determine if the application of CFRPs retrofit solution is suitable in a given environment and appropriate for the level of deterioration of the structure.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/113176 |
| Date | 13 January 2023 |
| Creators | Yu-Shan, Abril Victoria |
| Contributors | Civil and Environmental Engineering, Eatherton, Matthew R., Hebdon, Matthew Hardy, Case, Scott W., Shakiba, Maryam |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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