To investigate an evaluation method of collapse mechanisms and the safety limit of RC buildings, a shake-table test of a 1/4 scale model of a 4story RC structure with shear walls was carried out. The specimen was designed to exhibit a frame-sway mechanism in both directions. In the test, the first-floor wall failed in flexure in the X-direction as designed; however, the first-floor wall in the Y-direction failed in shear, which did not match the design. Moreover, collapse mechanism and safety limit of the whole frame was discussed comparing the analytical result with the test result.

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Shaking table test of a quarter-scale 20-story reinforced concrete building model was carried out. Employed input waves were kinds of long period and long duration ground motion. Test results showed that structural slabs were fully effective for building strength, which could be expressed in detailed analysis using nonlinear FEM. However, the observed hysteretic damping after yielding was fairly smaller than the expected by the current design custom, which caused smaller and unsafe estimated response than that observed in the test.

The authors propose a method for quantifying concrete cracks by means of crack area as the product of the crack width and crack length to evaluate the shielding performance of reinforced concrete walls. Cyclic loading tests on reinforced concrete shear wall specimens were performed, and the crack widths of the walls were measured in detail. The test results show that the crack area correlates with the drift angle of the wall. Furthermore, two methods for calculating the crack area through nonlinear finite element analysis are proposed. The calculated crack areas correspond well to those of the test specimens.

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