The Effects of Vibration on Compressive Strength of Newly Poured Foundation Concrete Pad

• Main Authors: Xiao –Di, 柯小迪
• Other Authors: Tzyy-Shiou Chang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/33363630713189784908

碩士 === 朝陽科技大學 === 營建工程系碩士班 === 94 === A series of tests were conducted in order to study the effects of earthquake vibrations at various setting times on compression strength of newly poured concrete foundation pads. The results of the study revealed that when vibrations were imposed at a setting time of 10 hrs. after the concrete was poured, the strength reduction for vibration, which is equivalent to an Intensity 3 earthquake, was less than 28% when compared to no vibration. The reduction is 28-36%, 36-46%, 46-50%, and greater than 50% for Intensity 4, 5, 6, and 7 earthquakes, respectively. The results also indicated that the compression strength of the newly poured concrete pad was severely reduced by vibration at setting times before the "critical time." The "critical time" found from the test results is less than 10 hrs., 10-17 hrs., 17-24 hrs., 24-27 hrs., and 27-34 hrs., for Intensity 3, 4, 5, 6, and 7 earthquakes, respectively. The vibration effects become less significant when they occur after the "critical time." In addition, the vibration effects on the concrete strength become minimal after the "minimal reduction time," which is found to be less than 40 hrs., 40-41 hrs., 41-46 hrs., 46-52 hrs., and 52-60 hrs. for Intensity 3,4,5,6, and 7 earthquakes, respectively. These study results provide preliminary information for future reference and application for earthquake engineering and related topics.