This study investigates stress transfer mechanisms of floor slabs in soft first-story buildings through static cyclic loading test on a three-dimensional frame specimen. The specimen consists of two soft first-story frames and one multi-story shear wall. In the test, the soft first-story frames formed an overall flexural collapse mechanism, while the multi-story shear wall experienced base sliding failure due to additional shear force from the soft frames to the wall via the floor slabs between them. The slab induced shear transfer was smaller than that predicted by the rigid floor assumptions, implying the need for modeling slabs appropriately in design.
