More Like this

1. Performance of externally bonded fiber-reinforced polymer retrofits in the 2018 Cook Inlet Earthquake in Anchorage, Alaska

   https://doi.org/https://doi.org/10.1177/87552930211028609  

   Tatar, Jovan; Sattar, Siamak; Goodwin, David; Milev, Sandra; Ahmed, Shafique; Dukes, Jazalyn; Segura, Christopher (August 2021, Earthquake spectra)

   null (Ed.)

   As part of the effort to improve the seismic performance of buildings in Alaska (AK), many of the deficient structures in Anchorage, AK, were retrofitted—some with externally bonded fiber-reinforced polymer (EBFRP) composite systems. The 2018 magnitude 7.1 Cook Inlet earthquake that impacted the same region offered an opportunity to evaluate the performance of EBFRP retrofits in a relatively high-intensity earthquake. This study summarizes the following findings of this field investigation: (1) the performance of EBFRP-retrofitted structures in the Cook Inlet earthquake and (2) the observations concerning the condition of FRP retrofits from over a decade of exposure in a subarctic environment. A deployment team from the National Institute of Standards and Technology (NIST) in collaboration with the University of Delaware (UD) Center for Composite Materials conducted post-earthquake inspections of EBFRP retrofits in multiple buildings to assess their performance during the earthquake and condition with respect to weathering. EBFRP debonding was documented with infrared thermography and acoustic sounding and the bond quality between EBFRP and concrete was assessed using pull-off tests. Visual inspections showed no major signs of earthquake damage in the EBFRP-retrofitted components. However, evaluation of debonding and pull-off test results suggested that outdoor conditions may have led to bond deterioration between EBFRP and concrete from installation defects that grew over time, freeze–thaw expansion from moisture present at the FRP/concrete interface, differences in thermal expansion of the materials, or a combination thereof. The carbon fiber–reinforced polymer (CFRP) bond to concrete was found to be more vulnerable to outdoor exposure than the glass fiber–reinforced polymer (GFRP) bond. Earthquake effects on FRP/concrete bond could not be assessed due to the lack of baseline data. 

   more » « less
2. Study of Agave Fiber-Reinforced Biocomposite Films

   https://doi.org/10.3390/ma12010099  

   Annandarajah, Cindu; Li, Peng; Michel, Mitchel; Chen, Yuanfen; Jamshidi, Reihaneh; Kiziltas, Alper; Hoch, Richard; Grewell, David; Montazami, Reza (January 2019, Materials)

   Thermoplastic resins (linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP)) reinforced by different content ratios of raw agave fibers were prepared and characterized in terms of their mechanical, thermal, and chemical properties as well as their morphology. The morphological properties of agave fibers and films were characterized by scanning electron microscopy and the variations in chemical interactions between the filler and matrix materials were studied using Fourier-transform infrared spectroscopy. No significant chemical interaction between the filler and matrix was observed. Melting point and crystallinity of the composites were evaluated for the effect of agave fiber on thermal properties of the composites, and modulus and yield strength parameters were inspected for mechanical analysis. While addition of natural fillers did not affect the overall thermal properties of the composite materials, elastic modulus and yielding stress exhibited direct correlation to the filler content and increased as the fiber content was increased. The highest elastic moduli were achieved with 20 wt % agave fiber for all the three composites. The values were increased by 319.3%, 69.2%, and 57.2%, for LLDPE, HDPE, and PP, respectively. The optimum yield stresses were achieved with 20 wt % fiber for LLDPE increasing by 84.2% and with 30 wt % for both HDPE and PP, increasing by 52% and 12.3% respectively. 

   more » « less
3. Adaptive Reuse of FRP Composite Wind Turbine Blades for Civil Infrastructure Construction

   Gentry, R.; Bank, L.; Chen, J. F.; Arias, F.; Al-Haddad, T. (July 2018, 9th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2018))

   The rapid growth in wind energy technology has led to an increase in the amount of thermosetting FRP composite materials used in wind turbine blades that will need to be recycled or disposed of in the near future. Calculations show that 16.8 million tons of waste from wind blades will need to be managed globally by 2030, increasing to 39.8 million tons by 2050. Three waste management route are possible: disposal, recycling or reusing. Currently, most FRP composites taken out of service are disposal of in landfills or are incinerated. Recycling options consist of reclamation of the constituent fibers or the resins by thermo–chemical methods or recycling of small pieces of granular FRP material as filler material by cutting, shredding or grinding. Reuse options consist of reusing the entire FRP blade or large parts of the blade in new structural applications. This paper reports on the potential for reusing parts of wind turbine blades in new or retrofitted architectural and civil infrastructure projects. The paper introduces the geometry, materials, and laminates typically used in wind blades and provides a snapshot of the sizes of wind blades likely to be available from the inventory of active turbines. Because the materials and manufacturing of commercial wind blades are proprietary, generic blade geometries and materials are discussed. These come from the Sandia National Laboratory and National Renewable Energy Laboratory, in the United States, and from OPTIMAT in the European Union. The paper presents an example of the geometry and material properties of structural elements cut from wind blades, using the Numerical Manufacturing and Design Tool (NUMAD), published by the Sandia National Laboratory. 

   more » « less
4. ADAPTIVE REUSE OF FRP COMPOSITE WIND TURBINE BLADES FOR CIVIL INFRASTRUCTURE CONSTRUCTION

   Gentry, T.R.; Bank, L.C.; Chen, J-F.; Arias, F.; Al-Haddad, T. (July 2018, Composites in Civil Engineering CICE 2018)

   The rapid growth in wind energy technology has led to an increase in the amount of thermosetting FRP composite materials used in wind turbine blades that will need to be recycled or disposed of in the near future. Calculations show that 4.2 million tons of waste from wind blades will need to be managed globally by 2035, increasing to 16.3 million tons by 2055. Three waste management route are possible: disposal, recycling or reusing. Currently, most FRP composites taken out of service are disposal of in landfills or are incinerated. Recycling options consist of reclamation of the constituent fibers or the resins by thermo–chemical methods or recycling of small pieces of granular FRP material as filler material by cutting, shredding or grinding. Reuse options consist of reusing the entire FRP blade or large parts of the blade in new structural applications. This paper reports on the potential for reusing parts of wind turbine blades in new or retrofitted architectural and civil infrastructure projects. The paper introduces the geometry, materials, and laminates typically used in wind blades and provides a snapshot of the sizes of wind blades likely to be available from the inventory of active turbines. Because the materials and manufacturing of commercial wind blades are proprietary, generic blade geometries and materials are discussed. These come from the Sandia National Laboratory and National Renewable Energy Laboratory, in the United States, and from OPTIMAT in the European Union. The paper presents a method for generating the geometry and material properties of structural elements cut from wind blades, using the Numerical Manufacturing and Design Tool (NUMAD), published by the Sandia National Laboratory. 

   more » « less
5. Seismic and Durability Assessment of Externally Bonded FRP Retrofits in Reinforced Concrete Structures After 2018 Anchorage, AK Earthquake

   https://doi.org/https://doi.org/10.1007/978-3-030-88166-5_106  

   Milev, Sandra; Ahmed, Shafique; Hassan, Mariam; Sattar, Siamak; Goodwin, David; Tatar, Jovan (November 2021, CICE 2021: 10th International Conference on FRP Composites in Civil Engineering)

   Ilki, Alper; Ispir, Medine; Inci, Pinar (Ed.)

   Externally bonded fiber-reinforced polymer (EBFRP) composites are a cost-effective material used for repair and seismic retrofit of existing concrete structures. Even though EBFRP composites have been extensively utilized over the past 20 years as seismic retrofits, there are few data documenting their performance in a real shaking event or after long-term use on concrete structures. In this study, semi-destructive and non-destructive techniques were employed to evaluate the performance and durability of EBFRP-retrofitted buildings that had experienced the 2018 Cook Inlet Earthquake in Anchorage, AK. The performance of EBFRP was evaluated and documented through photographic evidence. Acoustic sounding, infrared thermography, and bond pull-off tests were utilized to evaluate the quality of bonding between the EBFRP and concrete. EBFRP samples were also collected from building interiors and exteriors for chemical and thermal analysis to evaluate the long-term effects of environmental exposure. Although environmental conditions were found to influence the bond quality between the EBFRP composite and concrete substrate, no major signs of earthquake damage to the building components retrofitted with EBFRP were noted. Materials characterization results demonstrated no evidence of polymer matrix degradation in exterior EBFRP samples. 

   more » « less