It is very important to calculate natural frequency of the observatory tower correctly because it is keenly affected by wind response vibration due to its large slenderness ratio, weight and small damping ratio. Additionally, suggestion equation of natural frequency being used in the design phase has considerable difference between actual measured value thereby making it inappropriate to be used in the serviceability design of the observatory tower. Therefore, this paper conducted an ambient vibration measuring on 10 observatory towers through mobile-phone application thereby calculating the natural frequency and comparing the result with the domestic and foreign standards and that of the eigen-value analysis. This paper suggested approximate equation of the natural frequency of the observatory tower; T=0.0266H. The square of the corelation coefficient is 0.940, which is high.

1. 서론
 2. 진동계측
  2.1 계측 타워전망대의 건축개요
  2.2 계측장치
 3. 진동계측데이터
  3.1 기존 고유주기 제안식
  3.2 고유진동수 분석
  3.3 고유진동수 계측치의 근사식
  3.4 계측치와 국내외기준 및 해석치 비교
 4. 결론
 감사의 글
 References

• 문상현(서울과학기술대학교 건축과 석사과정) | Moon Sang-Hyouen
• 윤성원(서울과학기술대학교 건축학부 교수, 공학박사) | Yoon Sung-Won