Experimental investigation of the influence of joint connection details between existing buildings and added new frames on failure mode of retrofitted slabs for the vertical expansion of old buildings: Part II

Dismantling entire existing buildings can be circumvented by adding additional frames to provide more residence, thus avoiding the need to reconstruct buildings. The alternatives are to construct new frames on old apartment buildings in order to avoid entirely dismantling existing buildings. The conventional wall frames for super structures added onto existing buildings are replaced by frames consisting of composite beams and steel columns to minimize beam depth and weight of the load from the added frames. This paper studied joint connection types for the rehabilitation of old buildings to withstand lateral loads. Details of the joints between newly added steel columns and existing slabs are presented in this paper. The structural behaviors of anchored joints between the new 3‐story composite frames and an existing 15‐floor building were significantly investigated through extensive experiments. Complex failure modes were identified based on the test of the wall foundation types and the anchor types connecting the base plates to existing slabs. The authors previously reported that the flexural load‐bearing capacity of slabs was the dominant load‐resisting capacity. The column–slab joint connections introduced with experimental demonstrations in this study are expected to contribute to enhancing the lateral capacity of the extended buildings.