Advances in Computational Design

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Experimental study on bolt torque-tension relationship for different washer and nut combinations

  • Hwang, Seung-Hyeon (Department of Architectural Engineering, Kyonggi University) ;
  • Kim, Sanghee (Department of Architectural Engineering, Kyonggi University) ;
  • Yang, Keun-Hyeok (Department of Architectural Engineering, Kyonggi University)
  • Received : 2021.05.26
  • Accepted : 2021.08.22
  • Published : 2021.10.25
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Abstract

This experimental study was conducted to determine nut factors based on four combinations of washers and nuts. A prestressing force was applied to a long reinforcing bar using the torque-tension method. All the sets exhibited a linear trend. The nut factors for combinations of the flat washers and hex nuts, spring washers and hex nuts, flat washers and heat-treated nuts, and flat washers and self-locking nuts were 0.228, 0.224, 0.299, and 0.397, respectively. Additionally, the relaxation of the flat washers and hex nuts in a relatively long-term period (40 days in this study) was evaluated, and eight specimens subjected to various initial prestressing forces were analyzed. The average change in prestressing force was-3.98%.It is necessary to consider prestressing force loss for relatively long-term when prestressing force is applied to a long reinforcing bar.

Keywords

Acknowledgement

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2015R1A5A1037548) and by the Korea Agency for Infrastructure Technology Advancement funded by the Ministry of Land, Infrastructure and Transport of the Korean government (No. 21TMIP-C158687-02).

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