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Cyclic and Impact Resistance of FRP Repaired Poles

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Date Issued:
2015
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 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.
Title: Cyclic and Impact Resistance of FRP Repaired Poles.
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Name(s): Mohsin, Zainab, Author
Mackie, Kevin, Committee Chair
Makris, Nicos, Committee Member
Nam, Boo Hyun, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2015
Publisher: University of Central Florida
Language(s): English
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 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.
Identifier: CFE0005846 (IID), ucf:50936 (fedora)
Note(s): 2015-08-01
M.S.
Engineering and Computer Science, Civil, Environmental and Construction Engineering
Masters
This record was generated from author submitted information.
Subject(s): FRP Repaired Poles
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0005846
Restrictions on Access: public 2015-08-15
Host Institution: UCF

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