An Investigation of the Causes for Building Tilted or Collapsed during Earthquake

• Main Authors: Chun-Yi Su, 蘇純儀
• Other Authors: 許澤善
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/30898672470684276632

碩士 === 逢甲大學 === 土木工程學系 === 104 === The Ministry of the Interior (MOI) first included minimum earthquake loads in seismic design specifications of buildings in 1974, and these requirements had been revised on multiple occasions since then. Although the requirement of minimum earthquake loads for buildings have continued to increase, buildings that comply with seismic design specifications have continued to tilt and collapse during actual earthquakes. The author of this paper investigated old buildings that were constructed prior to the promulgation of specifications for seismic design specifications of buildings (with the example being the Language Building of Feng-Chia University) and buildings that maintained stability and safety during multiple major earthquakes constructed after the above-mentioned specifications were released (an example being the machine workshop and classroom of National Minsyong Vocational High School of Agriculture and Technology) in order to study the causes of tilting or collapsing of buildings during the October 22nd Chiayi Earthquake. Results supported that safety factor for seismic bearing capacity safety coefficient of building foundations during the earthquake and the earthquake-induced settlements would be the professional causes determining whether buildings would suffer from tilting or collapses during actual earthquakes. When seismic design specifications of buildings fail to consider these professional causes, even if the columns, girders, plates, and walls were compliant to seismic design specifications, the building would still suffer from tilts and collapses even if subject to actual earthquakes with magnitudes smaller than that of the designed one. Secondly, results of the analysis described in this paper showed that seismic designs should focus primarily on the selection of sites with better earthquake resistance or improve upon unstable sites to give better earthquake resistances. Constructing a building in an earthquake-resistant site would give it sufficiently high foundation bearing safety coefficient and low enough earthquake-induced settlements. This building would be capable of maintaining stability and safety during earthquakes even if it were constructed prior to the release of earthquake resistance design specifications released by the MOI. Conversely, if a building is built upon a site with no earthquake resistance, resulting in a foundation bearing safety coefficient that was too low or an earthquake-induced settlement that was too high, the building would tilt and collapse even if it satisfied the latest seismic design specifications. This paper therefore recommends identifying the true professional causes of earthquake damages prior to revising the seismic design specifications. Revisions to the said specifications should then be based upon these professional findings and conclusions in order to ensure that buildings compliant to the revised specifications would not tilt or collapse during actual earthquakes with magnitudes smaller than the designed threshold.