Analysis of slab-column connections in CFT sections without continuity of the tube

Abstract

[EN] When dealing with concrete-filled tube columns and RC slabs, it is usual to interrupt steel tubes in slab-column connections if the column is mainly compressed. Contractors do prefer to solve these connections with independent tubes, although innerreinforcements may be continuous through the slab. In these cases, both tubes from the upper and lower levels do have base plate connections, with a set of anchor bolts. This procedure saves a lot of time of global works, by making everything easier at the same time, as tubular profiles do not intersect the formwork.However, this reasonable design for slab-column joints suggest at least some questions about the strength of the concrete at the area of connection, where the tube has been interrupted. On the one hand, the load is transferred through concrete in the slab thickness, since there is no continuity of the tube; on the other hand, concrete at that point becomes triaxially confined due to the restriction to lateral deformation.This study analyses the validity of this connection method and the differences observed depending on the relative location of the column (corner, façade –lateral- or central pillars). Needless to say that the relative location of the column leads to differentconfinement patterns in concrete.