Variance among Primary, Secondary and Tie Beam
PRIMARY BEAMS: Primary beams belong to the beams which associate columns for delivering loads of a structure directly to the columns. Generally, primary beams remain shear connected or simply supported and they are arranged in a regular building structure. The depth of the primary beams remains more than secondary beams. Primary beams perform as a connector among columns and secondary beams.
SECONDARY BEAMS: The role of these types of beam is to associate primary beams for delivering loads of a structure to the primary beams. These beams are constructed to provide support and lessen the deflection of beams and slabs.
TIE BEAMS: The role of these types of beams is to associate two or more rafters in the roof or roof truss for reinforcing the entire building structure.
These beams do not bear the vertical load of slab or walls rather bear the axial compression. Usually, tie beams are applied in roof truss or in damp proof course at the plinth level.
Source : www.dailycivil.com