NEHRP Clearinghouse
- Title
- Determination of Earthquake Intensities from Chimney Damage Reports.
- File
- PB82103441.pdf
- Author(s)
- Whitman, R. V.; Becker, J. M.; Ho, A. D.
- Source
- National Science Foundation, Washington, DC. Engineering and Applied Science., June 1979, 108 p.
- Abstract
- An approach to determine earthquake intensities from chimney damage reports is presented. In particular, the intensity of Boston's Cape Ann Earthquake of November 18, 1755, is estimated. A detailed analysis of a two-story, heavy-timber frame house with a masonry chimney extant in 1755 was performed to determine (1) the dynamic response characteristics; (2) force levels in the structure when subjected to earthquake motions; (3) forces required to initiate damage; and (4) the approximate (lower bound) intensity of the 1755 earthquake. A standard analytical model, with basic mass and stiffness properties, was developed and a parametric study was performed to analyze the effects of the several chimney, house, and ground parameters involved in the study. Results indicated that the chimney-house system was quite stiff with a fundamental frequency of about 12 Hz. It was also observed that the higher modes contributed to the total response of the system. The effect of a gap in the chimney-house connection appeared to be an important consideration in determining chimney damage due to earthquakes. It was concluded that an earthquake intensity in the range of 0.15g to 0.04g would initiate damage to the various chimneys as modeled.
- Keywords
- Chimneys; Damage assessment; Earthquake resistant structures; Intensity; Massachusetts; Dynamic response; Earthquake engineering; Boston (Massachusetts); Theses; Cape Ann Earthquake; Earthquakes