Abstract:

Based on the test results of two three-story RC ( Reinforced Concrete) space slab-column structure models with weak stories,the interstory shear force-time curve during the pancake collapse under earthquake is analyzed for each story and is compared with that before the collapse. Then,the equivalent interstory shear force and its impulse on each story in the impact process are approximately estimated and compared with the lateral impulse to the upper structure of a simple model in the static initial state. The results show that ( 1) pancake collapse impact results in equivalent interstory shear forces with large values and very short durations in each story of the test model,which is a challenge to the lateral deformation-resisting capacity of non-weak stories; ( 2) with the increase in the structural weight over the weak story,the interstory shear forces in the impact process significantly increase;
and ( 3) under the pancake collapse impact,the lateral impulse to the upper structure of a simple model in the static initial state is about 4 ～ 5 times that of the test model at the same location with an equivalence point being zero percentage.

Key words: reinforced concrete, space slab-column structure, weak story, pancake collapse, interstory shear force, earthquake