BRI Research Paper


Planer Tests on Reinforced Concrete Shear Wall Assemblies. -U. S.-Japan Cooperative Research Program-.

H.Hiraishi*1, M.Yoshimura*2, H.Isoishi*3, S.Nakata*4; January, 1963. 63p.


This study was done as support tests for the pseudo-dynamic test of a full-scale seven story reinforced concrete building scheduled for 1980 under the "U.S.-Japan Cooperative Research Program Utilizing Large Scale Testing Facilities".

Tests were made on the shear wall-beam assemblies of the lower three stories of the internal structural frame in the ridge direction of the full-scale seven story building. Test specimens were of two kinds. One was a half-scale test specimen (W1) with reinforcements corresponding to the full-scale design building. The other (W2) was of the same cross-section and shape as W1 but with increased reinforcements and increased strength for the sake of comparison, since the full-scale seven story building has a low base shear at ultimate strength. The boundary beams at each story of the test specimens were connected to each other by tie bars with both pinned ends to prevent vertical displacement, so that bending moments of the boundary beam would decrease wall moment.

The moment distribution applied to the specimen was similar to that of the wall in the seven story buildings under the external forces of inverted triangular distribution. The controlled moment together with the axial force was applied to the test specimen at the top of the third story, by adjusting the load of two jacks installed vertically on each side of the top of the test specimen. Load hysteresis consisted mainly of repetitions to displacement values where considerable plasticization was expected from a preliminary seismic response analysis of the full-scale seven story building.

Detailed measurement was made of the horizontal and vertical displacements at the left and right ends of the respective stories, the stretching forces of the boundary beams in the hinge region, strains in the main and shear reinforcements of the beams and columns, and strains in the vertical and horizontal wall reinforcement.The test results were as follows:

i) In both W1 and W2, the load-deflection hysteresis displayed bending-type behavior with a decreasing loss of strength from cycle to cycle at the same displacement level. Final failure was a collapse of the column concrete on the compression side accompanied by a sharp decrease in strength.The rotation angle of the shear wall at the time of rupture was 1/50 for W2 and 1/40 for W1, but in the case of W1, a stable load-deflection hysteresis was maintained only to 1/50.
ii) The respective stories produced a nearly identical rotation angle.Particularly in W1, the deformation was mainly, determined by the rotation due to the elongation and shrinkage at the base of the shear wall.
iii) In both W1 and W2, all the vertical wall reinforcement at the bottom of the wall and the main reinforcements of the tensile side columns yielded before the rotation angle reached to 1/200. The main reinforcement of the boundary beam and the adjacent slab reinforcement also yielded before the rotation angle reached 1/200.
iv) The test specimens had no beams in the wall, so the shear cracking in the upper and lower stories penetrated the slab and produced continuous cracks throughout the upper and lower stories. However, the absence of beams had little influence on -the rigidity and strength.
v) The shear strength of the test specimens was considerably higher than the maximum flexural strength, so in the pseudo-dynamic test of the full-scale seven story building, the shear wall is not expected to fail in shear.

*1 Chief Researcher, Structure Division, Structural Engineering Department
*2 Research Member, Structural Dynamic Division, Structural Engineering Department
*3 Assistant Research Member, Construction Techniques Division, Production Department
*4 Head, Structure Division, Structural Engineering Department

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