Finite Element Analysis of Frames with Composite Transfer Beams

A transfer beam is specifically defined as a beam that transmits loads from the upper closely spaced columns or walls acting on it to the widely spaced columns or walls supporting it. The discontinuity of the vertical structural members is the most significant characteristic of a structural system with transfer beams because it makes the mechanism of the system more complex than that of a regular structural system. The provision of transfer beams in the buildings cannot be avoided due to its functional requirements like parking facilities, public lobbies, and large openings at the ground floor level for shopping malls etc. But this provision of transfer beams creates soft storey effect in the buildings. Buildings with less than 70% stiffness of the floor immediately above it is classified as soft storey. Due to this soft storey effect, the flexibility of that floor increases and results in extreme deflection, which in turn leads to concentration of forces at the immediate above floors followed by large plastic deformations. In addition, most of the energy developed during earthquake is dissipated by the column of soft stories. The aim of the study is to reduce the soft storey effect of buildings with transfer beams by increasing the stiffness of soft storey equal to the stiffness of immediately above storey. For this the intermediate column size of ground floor of the frame is increased by 10% and corresponding stiffness and deformations are analysed using ANSYS software. To avoid the large sections of column a beam was introduced at the plinth level to reduce the soft storey effect. The results obtained shows increased stiffness and reduced deformations.