| Author | Gerasmo, Federico John R. |
| Call Number | AIT Thesis no. ST-94-8 |
| Subject(s) | Buildings--Earthquake effects
|
| Note | A thesis submitted in pa1tial fulfillment of the requirements for the degree of Master of
Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | This study deals with the development of a low-cost aseismic base isolation system. The main
motivation behind this study was the protection of houses of poor families in high-seismicity regions.
An isolation system based on pure friction was selected to be studied because of its low cost, simplicity and ease of constrnction. This system may be easily incorporated at the bottom ofload-bearing
walls of masonry, earthen and adobe houses which compose the majority of rural houses in many
high-seismic-risk regions.
The Pure-Friction (P-F) system is constrncted by laying a good sliding device between two
smoothened, match-casted concrete plates at the bottom of the walls. The performance of this isolation system is dependent basically on the friction coefficient of the device between the interface.
Static friction tests were initially carried out to identify suitable materials to be used as isolation
devices. Sand, graphite, steel balls, asphalt felt, silica powder and fly ash were tested. The tests
showed that three of the devices possessed good static friction characteristics, namely, sand, graphite
and steel balls.
Dynamic tests using the shaking table were conducted to observe the performance of the
devices in a more realistic condition. The results of the tests revealed that the P-F system can be
very effective in isolating a structure from earthquake ground motion. However, these results were
not general. The isolation system was very effective for high frequencies of oscillation only. For
low frequencies, there were cases were amplification of response occured. It is believed that the
amplification of the response was due to variation of the surface area in the match-casted interface
and that an improvement in the interface (i.e. more plane) could greatly enhance the performance
of the system.
Finally, the sand, graphite and small rolling bearings were proven to possess satisfactory
sliding characteristics and may be used as isolation devices. However, to assure the effectiveness
of the isolation system, further studies are recommended to focus on the kinetic coefficient of friction
and the surface condition of the interface which are crucial for the design of an effective sliding
isolation system.
|
| Year | 1994 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Pisidhi Karasudhi |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |