Experimental investigation of uplift on seismic base isolators /

Erkakan, Evren
Elastomeric rubber bearings reinforced with steel shims, are used to provide structural support in vertical direction and allow horizontal movements for the structure subjected to earthquake and thermal loads. Generally, it is known that tensile stress or uplift may occur when the structure is subjected to strong ground motion or structure have large height-to-width aspect ratio to develop a stability concern subjected to lateral loads. The main focus of this research is to investigate the change in characteristic behavior of bearings under vertical tension load and horizontal load since limited information is available on this combination of loads. For this purpose, four bearings having the same shape factor with different sizes and two other bearings are examined. They are subjected to a series of staged and cyclic loads. Shear modulus values under different vertical loads are calculated according to both TS EN 1337-3 and BS 5400 specifications separately. It is observed that shear modulus decrease with Mullin’s Effect for standard bearings while decreasing in shear modulus of concave edged bearing related to strain amplitude. At the end of study, it can be stated that considerable results are obtained and this pioneering research indicate that bearings can take tension loads while subjected to horizontal loads. Still the subject needs further research and testing.
Citation Formats
E. Erkakan, “Experimental investigation of uplift on seismic base isolators /,” M.S. - Master of Science, Middle East Technical University, 2014.