The Earthquake Engineering Online Archive

Shaking table testing of a reinforced concrete frame with biaxial response

Oliva, Michael G.

UCB/EERC-80/28, Earthquake Engineering Research Center, University of California, Berkeley, 1980-10, 205 pages (530/O43/1980)

The program in this report involved testing of a one-third scale two-story reinforced concrete frame, having rectangular section columns, with inelastic biaxial motion induced through earthquake excitation on a shaking table. Close inspection of the experimental response, and comparison with previous test results on a similar frame under pure uniaxial motion, found that biaxial motion seriously reduced the column yield strength. Local and global response characteristics indicated a tremendous amount of interaction between the rectangular column's strong axis motion and weak axis response. Weak axis stiffness was reduced to less than one-third the initial value, through strong axis interaction, associated with narrow hysteretic load-deformation response, characteristic of a low-energy absorption mechanism. Analytical correlation with experimentally measured response, considering response independently along the frame's major axes, was unsuccessful. Necessary modifications to current analysis techniques, for accurate modeling of multi-axial loading, including biaxial bending, of reinforced concrete members is discussed.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-80-28.pdf (25 MB)