Axial force of the bolt is very important for structural stability. To obtain stability of the structure, axial force of the bolt should satisfy the specification and be maintained over the time. Hence, It is important to the axial force of the bolt is measured and it manages. However, measuring of the axial force using sensors is very expensive. Torque method using frequently in the field is difficult to confirm accurately by the torque coefficient change. In this study, measuring of axial force using elastic force of the spring washer was studied. First, the relational formula is drawn about the pressure in which the spring washer model changes to the annular of the plane state. According to the axial force of the bolt, the necessity height of the spring washer is presented and the finite-element analysis model is recommended. The analysis model research, generally, the axial force of high strength bolt is confirmed. It expands to confirmation of the large caliber bolt.

ABSTRACT
 1. 서 론
 2. 축력 확인에 대한 DTI의 작용 원리와 스프링와셔 작용원리의 비교
 3. 유한요소 해석을 통한 스프링 와셔의 거동 확인
 4. 결론
 Reference

• 주정수(서울시립대학교 건축공학과) | Ju Jeong Su
• 황슬기(서울시립대학교 건축공학과) | Hwang Seul Ki
• 박용필(㈜아원구조엔지니어링) | Park Young Pil
• 나환선(한전 전력연구원) | Nah Hwan Seon
• 최성모(서울시립대학교 건축공학과) | Choi Sung Mo 교신저자