SuperSized DoubleLayer Pultruded Gratings

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Super-Sized Double-Layer Pultruded Gratings

• by
• Lawrence Bank
• Michael Oliva
• Jeffrey Russell
• David Jacobson
• Mack Conachen
• University of Wisconsin, Madison, WI
• Bruce Nelson
• Dennis McMonigal
• Strongwell, Chatfield, MN

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Overview of Presentation

• Objectives of the Research
• Fabrication of Pultruded Grid
• Laboratory testing
• Development of Specifications
• Field implementation of FRP deck next to a twin
  bridge with conventional construction

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Objective of the Research

• Demonstrate feasibility of producing 8 ft by 40
  ft double layer pultruded FRP grids (gratings)
  and using them as a reinforcement system for a
  concrete highway bridge.
• Conduct slab testing, material testing, develop
  material and performance specifications, and
  implement the system in a new highway bridge deck
  in the State of Wisconsin.

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Super-size Double Layer Grating Panel
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Double-Layer Panel During Fabrication
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Detail of Panel Shear Connector
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Overlapping splice between Double Layer Panels
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Simply-Supported FRP Reinforced Concrete Slab Test
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Continuous FRP Reinforced Concrete Slab Test
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Results of FRP Reinforced Slab Tests
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FRP Property Specification

• FRP Grid Manufacturer was required to conduct
  tests and certify 9 mechanical and 6 physical
  property values
• Mechanical properties Longitudinal Tensile
  Strength, Transverse Tensile Strength,
  Longitudinal Compressive Strength, Transverse
  Compressive Strength, Long. Short Beam Shear
  Strength, Longitudinal Tensile Modulus,
  Longitudinal Compressive Modulus, In-Plane Shear
  Stiffness, Major (longitudinal) Poisson Ratio
• Physical properties Fiber Volume Fraction,
  Barcol Hardness, Glass Transition Temperature,
  Water absorption, Long. Coeff. of Thermal
  Expansion, Trans. Coeff. of Thermal Expansion

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Performance Tests for Double-Layer FRP Grating
Vertical Load Test
Horizontal Load Test
Racking Load Test
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Double-layer gratings at Bridge Site
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Placement of Individual Double-layer Grating on
Bridge
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Double-layer Gratings in Place Prior to Concrete
Pour
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Concrete Casting over the FRP Double-layer
Grating Reinforcement
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Cost Analysis of Steel Reinforcing vs. FRP
Reinforcing
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Conclusions

• Super-sized double layer pultruded gratings
  were successfully fabricated.
• The structural performance of concrete slabs
  reinforced with the double layer grids was
  proven.
• The double layer grids decreased construction
  time and hence labor and equipment costs.
• The initial cost of the double layer grids was
  significantly more than the steel rebars.