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Cyclic and Impact Resistance of FRP Repaired Poles
Title
Cyclic and Impact Resistance of FRP Repaired Poles.
Creator
Mohsin, Zainab, Mackie, Kevin, Makris, Nicos, Nam, Boo Hyun, University of Central Florida
Abstract / Description
Sign and signal structures involved in vehicular accidents are often partially damaged, and it ispossible to repair them instead of replacing them, even when the extent and severity of the damageare substantial. The replacement of these poles is costly and involves interruption for pedestriansand traffic. Therefore, some trials were performed to retrofit these poles in-situ with low cost andshort time. Previous research has substantiated that the damage can decrease the strength of thethese...
Show moreSign and signal structures involved in vehicular accidents are often partially damaged, and it ispossible to repair them instead of replacing them, even when the extent and severity of the damageare substantial. The replacement of these poles is costly and involves interruption for pedestriansand traffic. Therefore, some trials were performed to retrofit these poles in-situ with low cost andshort time. Previous research has substantiated that the damage can decrease the strength of thethese structures with increasing the dent depth and the use of externally-bonded fiber-reinforcedpolymer (FRP) composites are beneficial to repair them. The composite systems were comprisedof glass or basalt fibers paired with epoxy or polyurethane matrices. The effectiveness of FRPin repairing the damaged poles was demonstrated in previous tests on dented poles using 3-point,4-point, and cantilever bending tests. The repair systems were able to develop the load carryingcapacity of the damaged poles, and their behaviors were controlled by various types of failuremodes like yielding of the metallic substrate, FRP tensile rupture, FRP compressive buckling, anddebonding of FRP from the substrate.This thesis investigates the resistance of repaired full-scale metallic poles retrieved from the fieldfor monotonic, cyclic, and impact loading. These poles, which have rounded and multi-sided crosssections with and without access ports, were dented in the field or dented mechanically in thelaboratory and repaired with the same repair systems mentioned previously. Six of these poleswere mounted horizontally in a cantilever configuration to test them monotonically, while three ofthem were tested cyclically. In both tests, the load was applied as a point load at 9 ft from the baseplate. Additionally, two poles were mounted vertically using a cantilever configuration to test themfor impact. This test was performed by hitting the poles using an impact pendulum with a 1100 kgmass.The results of static tests show that the repair systems failed because of the aforementioned failuremodes. However, most of the failure was located outside the dented region, which indicates theeffectiveness of these repair systems in restoring the capacity of the damaged area. During thefatigue tests, the repair experienced no damage before weld rupture in the original steel tube-baseplate connection. Moreover, the repair systems proved their effectiveness in resisting the impactload, because they were ruptured at the contact region between the pole and the impactor at thetime the poles were deformed at the free side of the poles, as well as the impact side, during thetest.In all these tests, the access ports affected the behavior of the repaired poles. Depending on thegeometry of the pole, metal substrate, and dent depth and location, FRP repair system recommendationswill be presented.
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Date Issued
2015
Identifier
CFE0005846, ucf:50936
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005846
Characterization of Impact Damage and Fiber Reinforced Polymer Repair Systems for Metallic Utility Poles
Title
Characterization of Impact Damage and Fiber Reinforced Polymer Repair Systems for Metallic Utility Poles.
Creator
Johnson, Cara, Mackie, Kevin, Tatari, Mehmet, Chopra, Manoj, University of Central Florida
Abstract / Description
Previous studies have demonstrated that the behavior of ber reinforced polymers(FRPs) bonded to metallic utility poles are governed by the following failure modes; yieldingof the metallic substrate, FRP tensile rupture, FRP compressive buckling, and debonding ofFRP from the substrate. Therefore, an in situ method can be devised for the repair of utilitypoles, light poles, and mast arms that returns the poles to their original service strength.This thesis investigates the eect of damage due to...
Show morePrevious studies have demonstrated that the behavior of ber reinforced polymers(FRPs) bonded to metallic utility poles are governed by the following failure modes; yieldingof the metallic substrate, FRP tensile rupture, FRP compressive buckling, and debonding ofFRP from the substrate. Therefore, an in situ method can be devised for the repair of utilitypoles, light poles, and mast arms that returns the poles to their original service strength.This thesis investigates the eect of damage due to vehicular impact on metallic poles,and the eectiveness of externally-bonded FRP repair systems in restoring their capacity.Damage is simulated experimentally by rapid, localized load application to pole sections,creating dents ranging in depth from 5 to 45% of the outer diameter. Four FRP compositerepair systems were selected for characterization and investigation due to their mechani-cal properties, ability to balance the system failure modes, and installation eectiveness.Bending tests are conducted on dented utility poles, both unrepaired and repaired.Nonlinear nite element models of dented and repaired pole bending behavior aredeveloped in MSC.Marc. These models show good agreement with experimental results,and can be used to predict behavior of full-scale repair system. A relationship between dentdepth and reduced pole capacity is developed, and FRP repair system recommendations arepresented.
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Date Issued
2013
Identifier
CFE0004697, ucf:49872
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004697
Failure Analysis of Impact-Damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites
Title
Failure Analysis of Impact-Damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites.
Creator
Slade, Robert, Mackie, Kevin, Yun, Hae-Bum, Gou, Jihua, University of Central Florida
Abstract / Description
Metallic utility poles, light poles, and mast arms are intermittently damaged by vehicle collision. In many cases the vehicular impact does not cause immediate failure of the structure, but induces localized damage that may result in failure under extreme service loadings or can promote degradation and corrosion within the damaged region. Replacement of these poles is costly and often involves prolonged lane closures, service interruption, and temporary loss of functionality. Therefore, an in...
Show moreMetallic utility poles, light poles, and mast arms are intermittently damaged by vehicle collision. In many cases the vehicular impact does not cause immediate failure of the structure, but induces localized damage that may result in failure under extreme service loadings or can promote degradation and corrosion within the damaged region. Replacement of these poles is costly and often involves prolonged lane closures, service interruption, and temporary loss of functionality. Therefore, an in situ repair of these structures is required.This thesis examines the failure modes of damaged metallic poles reinforced with externally-bonded fiber reinforced polymer (FRP) composites. Several FRP repair systems were selected for comparison, and a set of medium and full-scale tests were conducted to identify the critical failure modes. The material properties of each component of the repair were experimentally determined, and then combined into a numerical model capable of predicting global response.Four possible failure modes are discussed: yielding of the unreinforced substrate, tensile rupture of the FRP, compressive buckling of the FRP, and debonding of the FRP from the substrate. It was found that simple linear, bilinear, and trilinear stress-strain relationships accurately describe the response of the composite and substrate components, whereas a more complex bond-slip relationship is required to characterize debonding. These constitutive properties were then incorporated into MSC.Marc, a versatile nonlinear finite element program. The output of the FEM analysis showed good agreement with the results of the experimental bond-slip tests.
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Date Issued
2012
Identifier
CFE0004262, ucf:49514
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004262