# Shear Transfer Mechanism between CFRP Grid and EPS Rigid Foam Insulation of Precast Concrete Sandwich Panels

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## Abstract

**:**

## 1. Introduction

## 2. Background

## 3. Scope of the Current Research

## 4. Experimental Program

#### 4.1. General

#### 4.2. Material Properties

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#### 4.3. Test Setup

#### 4.4. Instrumentation

## 5. Test Results and Discussion

#### 5.1. Specimens with 2″ Insulation

#### 5.2. Specimens with 4″ Insulation

#### 5.3. Comparison of the EPS.24.2.MMGRID Specimens with 2″ Insulation

#### 5.4. Comparison of EPS.24.4.MMGRID Specimens with 4″ Insulation

#### 5.5. Effect of Rigid Foam Insulation Thickness

#### 5.6. Failure Modes

## 6. Analysis

#### 6.1. Shear Modulus

^{2}), t is the thickness of the rigid foam (mm), L is the length of the grid segment and specimen (mm), ${A}_{sa}$ is the total contact surface area between the insulation and both surfaces of the central concrete wythe (mm

^{2}), w is the width of the specimen (mm), and ${\u2206}_{i,v}$ is the relative displacement between the central concrete core and the two outer concrete wythes of the specimen at 50% of the peak load level (mm).

#### 6.2. Design Equation

#### 6.3. Predicted vs. Measured Average Shear Flow Capacities

## 7. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 17.**Effect of EPS insulation thickness: shear flow vs. average deflection graph of EPS.24.2.MMGRID and EPS.24.4.MMGRID specimens.

**Figure 22.**Shear modulus vs. insulation thickness graph of EPS.24.2.MMGRID and EPS.24.4.MMGRID specimens.

**Figure 23.**Predicted values from the design equation [10] vs. measured average shear flow (1 lb/in = 0.2 N/mm).

**Figure 24.**Predicted values from the ICC-ES AC422 equation [22] based on a 99.7% confidence interval vs. measured average shear flow (1 lb/in = 0.2 N/mm).

**Figure 25.**Predicted values from the Choi et al. equation [17] based on a 80% confidence interval vs. measured average shear flow (1 lb/in = 0.2 N/mm).

Specimen Designation | Foam Type | Panel Width [ft] | Grid Spacing [in] | Foam Thickness [in] |
---|---|---|---|---|

EPS.24.2.MMGRID.1 | EPS | 4 | 24 | 2 |

EPS.24.2.MMGRID.2 | ||||

EPS.24.2.MMGRID.3 | ||||

EPS.24.4.MMGRID.1 | 4 | |||

EPS.24.4.MMGRID.2 | ||||

EPS.24.4.MMGRID.3 |

**Table 2.**Material properties of the EPS foam insulation [10].

Foam Type | Density [pcf.] | Compressive Strength (10% Deformation) [psi.] | Modulus of Elasticity [psi.] |
---|---|---|---|

EPS | 1 | 10–14 | 180–220 |

^{3}, 1 psi. = 6.9 kN/m

^{2}.

Specimen Designation | Peak Load [lbs.] | Shear Flow [lb/in] | Average Shear Flow [lb/in] | Standard Deviation [lb/in] |
---|---|---|---|---|

EPS.24.2.MMGRID.1 | 74,252 | 309 | 311 | |

EPS.24.2.MMGRID.2 | 75,363 | 314 | 2.7 | |

EPS.24.2.MMGRID.3 | 74,258 | 309 | ||

EPS.24.4.MMGRID.1 | 52,253 | 218 | 225 | |

EPS.24.4.MMGRID.2 | 58,924 | 246 | 18.5 | |

EPS.24.4.MMGRID.3 | 50,531 | 211 |

**Table 4.**Gamma factors determined by Bunn [10].

EPS | γ_{type} | Insulation Thickness[in] | γ_{thickness} | Grid Spacing [in] | γ_{Spacing} | Orientation | γ_{orientation} | q_{baseline}[lb/in] |

1.8 | 2 | 1.5 | 24 | 1.2 | Vertical | 1 | 100 | |

4 | 1.3 |

Specimen Designation | Insulation Type | Insulation Thickness [in] | Grid Spacing [in] | Measured Shear Flow Capacity [lb/in] | Predicted Shear Flow Capacity [lb/in] |
---|---|---|---|---|---|

EPS.24.2.MMGRID.1 | EPS | 2 | 24 | 309 | 324 |

EPS.24.2.MMGRID.2 | 314 | ||||

EPS.24.2.MMGRID.3 | 309 | ||||

EPS.24.4.MMGRID.1 | 4 | 218 | 281 | ||

EPS.24.4.MMGRID.2 | 246 | ||||

EPS.24.4.MMGRID.3 | 211 |

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**MDPI and ACS Style**

Sevil Yaman, T.; Lucier, G.
Shear Transfer Mechanism between CFRP Grid and EPS Rigid Foam Insulation of Precast Concrete Sandwich Panels. *Buildings* **2023**, *13*, 928.
https://doi.org/10.3390/buildings13040928

**AMA Style**

Sevil Yaman T, Lucier G.
Shear Transfer Mechanism between CFRP Grid and EPS Rigid Foam Insulation of Precast Concrete Sandwich Panels. *Buildings*. 2023; 13(4):928.
https://doi.org/10.3390/buildings13040928

**Chicago/Turabian Style**

Sevil Yaman, Tugce, and Gregory Lucier.
2023. "Shear Transfer Mechanism between CFRP Grid and EPS Rigid Foam Insulation of Precast Concrete Sandwich Panels" *Buildings* 13, no. 4: 928.
https://doi.org/10.3390/buildings13040928