EXPERIMENTAL STUDY ON PANCAKE COLLAPSE OF RC FRAME-SHEAR WALL STRUCTURES

Tests on pancake collapse of three one-storey RC frame-shear wall model structures, including pseudo-static test stage first and then pushover test stage, were conducted. The pancake collapse modes of the model structures and the time histories and planar distributions of the impact loads, which related to the second test stage, are reported in this paper. Test results show that: ① the out-of-plane break of shear walls and increasing of axial load ratios of columns are main causes of the pancake collapse of frame-shear wall structures; ② the impact process related to the pancake collapse involves complex and dynamic contacts of structural members, leading two groups of fluctuating in the time histories of impact loads; and ③ the impact loads are significantly affected by the materials of structural members, the maximum total impact load related to upper concrete members and a lower steel plate is 7.90 times of the total weight over and including the collapse story (i.e., the slab and beams’ weights, half of the shear wall and columns’ weights, and all the additional weights), and the maximum total impact load related to upper concrete members and a lower composite plate is only 3.58 times of the total weight over and including the collapse story.