Experimental investigation of slab joints between existing buildings and new frames for vertical expansion; [Part I

Abstract

Vertical additions can be made to existing buildings to provide more residences while avoiding the need to fully dismantle and reconstruct the buildings. Super-structural frames consisting of shallow composite beams and steel columns can be prefabricated as modular units, replacing the wall frames that are conventionally constructed in existing bearing wall buildings. A lightweight modular construction introduced in this study minimizes the needed structural reinforcement of frames below, enabling quicker and safer assembly of frames relative to traditional wall frame construction. This paper introduces joint details between added steel columns and existing slabs. Extensive experimental investigations were performed to study the structural behavior of the suggested joints. Eight full-scale specimens were loaded to failure to evaluate the structural applicability and reliability of the connecting methods introduced in this study, and to identify any problems with the vertical additions. The present work was also intended to find effective design procedures to those issues, and to provide test data for use in detailed analytical investigation of the structural behavior. Regardless of the connection method and the failure mode, all specimens demonstrated stable structural performance within the range of loadings that are expected during the service life of vertically extended buildings.