# Influence of Morphology Characteristics on Shear Mechanical Properties of Sawtooth Joints

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## Abstract

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## 1. Introduction

## 2. Specimen Preparation and Test Scheme

## 3. Test Results and Analysis

#### 3.1. Shear Stress–Shear Displacement Curve

#### 3.2. Shear Characteristics Analysis Based on Mohr–Coulomb Criterion

#### 3.3. Empirical Equation for Shear Strength of Joints

#### 3.4. Analysis of Failure Mechanism

_{B}, which can be solved as follows:

## 4. Conclusions

- (1)
- The shear stress under each sawtooth angle increased with increasing shear displacement. When the sawtooth angle of the joints was small, there was not a significant decrease between the shear strength and the residual shear strength, and the size of the drop was also smaller. The peak shear displacement showed a trend of first increasing and then decreasing with increasing normal stress, but the normal stress corresponding to the transition at different sawtooth angles was different.
- (2)
- The shear strength of joints at each sawtooth angle increased with the increase of the normal stress. The Mohr–Coulomb criterion was used to analyze the shear strength of the joints. It was found that the cohesion c and the internal friction angle α both increased nonlinearly with increasing sawtooth angle, but the increasing trend was different.
- (3)
- By introducing the function relation between cohesion and the internal friction angle and sawtooth angle into the shear strength formula of joints, an empirical equation for shear strength considering sawtooth angle was established.
- (4)
- The shear failure of sawtooth joints can be divided into two modes: the “saw-toothed sliding gnawing failure mechanism” (SSG) and the “tensile fracture mechanism” (TFM). With increasing sawtooth angle and normal stress, the shear failure mode ranges from slipping to slip gnawing to complete gnawing. The tensile fracture mechanism mainly occurs at high sawtooth angles.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 3.**Shear stress–shear displacement curves of joints with different sawtooth angles: (

**a**) Sawtooth angle of 0°; (

**b**) Sawtooth angle of 10°; (

**c**) Sawtooth angle of 20°; (

**d**) Sawtooth angle of 30°; (

**e**) Sawtooth angle of 45°.

**Figure 9.**Saw-toothed sliding gnawing failure mechanism of joints. (

**a**) Slip failure at 10° sawtooth angle under 0.4 MPa normal stress; (

**b**) Slip gnawing failure at 20° sawtooth angle under 1.2 MPa normal stress; (

**c**) Complete gnawing failure at 45° sawtooth angle under 2.0 MPa normal stress.

**Figure 11.**Tensile fracture mechanism. (

**a**) Tensile crack of 45° sawtooth angle under 0.8 MPa normal stress. (

**b**) Tensile crack of 30° sawtooth angle under 1.6 MPa normal stress.

Sawtooth Angle/° | Normal Stress/MPa | Loading Rate | Number of Samples |
---|---|---|---|

0 | 0.4, 0.8, 1.2, 1.6, 2.0 | 1 mm/min | 15 |

10 | 15 | ||

20 | 15 | ||

30 | 15 | ||

45 | 15 |

Sawtooth Angle φ (°) | Cohesion c (Mpa) | Internal Friction Angle α (°) |
---|---|---|

0 | 0 | 40.79 |

10 | 0.282 | 46.45 |

20 | 0.616 | 50.87 |

30 | 1.557 | 54.44 |

45 | 2.466 | 55.55 |

Sawtooth Angle (°) | Normal Stress (MPa) | ||||
---|---|---|---|---|---|

0.4 | 0.8 | 1.2 | 1.6 | 2.0 | |

10 | Slipping | Slip gnawing | |||

20 | Slipping | Slip gnawing | |||

30 | Slip gnawing | Complete gnawing | |||

45 | Slip gnawing | Complete gnawing |

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**MDPI and ACS Style**

Hu, H.; Zhang, X.; Qin, J.; Lin, H. Influence of Morphology Characteristics on Shear Mechanical Properties of Sawtooth Joints. *Buildings* **2022**, *12*, 886.
https://doi.org/10.3390/buildings12070886

**AMA Style**

Hu H, Zhang X, Qin J, Lin H. Influence of Morphology Characteristics on Shear Mechanical Properties of Sawtooth Joints. *Buildings*. 2022; 12(7):886.
https://doi.org/10.3390/buildings12070886

**Chicago/Turabian Style**

Hu, Huihua, Xing Zhang, Jianxin Qin, and Hang Lin. 2022. "Influence of Morphology Characteristics on Shear Mechanical Properties of Sawtooth Joints" *Buildings* 12, no. 7: 886.
https://doi.org/10.3390/buildings12070886