DISPLACEMENT VERSUS FORCE-SEEKING EFFECTS FOR REINFORCED CONCRETE FRAMES

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.

• Supplemental Notes:
  • From the American Concrete Institute Annual Convention, Symposium on Reinforced Concrete Structures in Seismic Zones, San Franciso, 1974.
• Corporate Authors:

  American Concrete Institute

  P.O. Box 19150, Redford Station, 22400 Seven Mile Road
  Detroit, MI  United States  48219
• Authors:
  • Ernst, G C
  • Smith, G M
• Conference:
  • From the American Concrete Institute Annual Convention, Symposium on Reinforced Concrete Structures in Seismic Zones, San Franciso, 1974.
• Publication Date: 1977

Media Info

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

Subject/Index Terms

• TRT Terms: Beams; Concrete construction; Concrete tests; Continuously reinforced concrete pavements; Dislocation (Geology); Dynamic loads; Earthquake resistant design; Earthquake resistant structures; Force; Frames; Material reinforcement; Oscillation; Reinforced concrete; Structural analysis; Structural members
• Uncontrolled Terms: Dynamic response; Reinforced concrete beams
• Old TRIS Terms: Continuous reinforcement; Structural frames
• Subject Areas: Bridges and other structures; Highways;

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