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Effects of Amount and Arrangement of Wall-Panel Reinforcement on Hysteretic Behavior of Reinforced Concrete Walls.
Iliya, R.; Bertero, V. V.
National Science Foundation, Washington, DC., February 1980, 183 p.
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This report presents the experimental results obtained in the third phase of an ongoing investigation on the seismic behavior of reinforced concrete walls. The ultimate objectives of this investigation are to find ways of designing and constructing R/C walls with large energy absorption and dissipation capacities under the effects of severe seismic excitations and to develop practical methods for the seismic design of combined wall-frame structural systems. Although the main objective of the studies reported here was to investigate the effects of the amount and arrangement of wall-panel reinforcement on the overall seismic performance of the walls, additional objectives were to study (1) the effectiveness of the epoxy-injection technique for repairing damaged walls, (2) methods of strengthening walls after their local failure, and (3) the effects of construction joints. Two one-third scale models of the three bottom stories of the wall of a ten-story frame-wall R/C building designed according to UBC/73 seismic code requirements were constructed and studied experimentally. In one model equal amounts of horizontal and vertical reinforcement were used in the wall panel, while in the other specimen the panel reinforcement was arranged diagonally at 45 degrees. Each specimen was subjected to three series of three tests. In the first series, the specimen was loaded under generalized loading (cyclic with full reversals) up to first yielding of all the reinforcing bars at the edge member in tension. Then the specimen was repaired by injecting epoxy in the cracks. In the second series, after being loaded with full deformation reversal cycles up to first yielding, the specimen was loaded with montonically increasing deformations up to failure, which occurred in the first story. After repairing and strengthening this first story, the model was loaded under cyclic loading, inducing full deformation reversals, up to failure. The results obtained are evaluated and discussed in detail and then compared with the results from experiments carried out on the six previous studied in the first and second phases of the ongoing investigation. The report concludes with some recommendations for improving present seismic code provisions and for future research.
Buildings; Earthquake engineering; Earthquake resistant structures; Loads (Forces); Seismic design; Earthquakes; Reinforced concrete; Walls; Concrete construction; Panels