Oscillatory motions were applied to continuous reinforced concrete frames under laboratory control for both displacement and force seeking conditions. It was found that a shift in the axis of oscillation can occur when full plastic response develops. Force seeking oscillations greater than those required to produce full plastic response were found to shift the axis of oscillation further in the direction of the initial shift, thereby resulting in a crawling of the displacement of the frame. In such action, structural damage can be exceptionally severe. For the testing, three basically different procedures were selected. All frames carried a simulated gravity load, but the lateral loading effect was produced by simulated earthquake displacements, a "load seeking" condition, or a "displacement seeking" situation. One frame was repaired after collapse and retested. Structural distress was found to occur with steel strains in the yield plateau, and such distress progressed with severity as soon as the ultimate moment was attained at a critical section. Degradation of load resistance accompanied repeated cyclic loading at or beyond steel yield strains. Results pointed to the need to include cycling under force seeking conditions at and beyond steel yield strains at each critical section.

Media Info

  • Features: References;
  • Pagination: p. 227-246

Subject/Index Terms

Filing Info

  • Accession Number: 00188909
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: SP-53 Conf Paper
  • Files: TRIS
  • Created Date: Mar 28 1979 12:00AM