Transfer Girder for Floating Column

Location: Surat, Gujarat
About Project
Ashirwaad Textile, a project located in Surat, is an industrial complex of 4,740 sq. ft. comprising of 10 floors including G+7 floors and two basement parking. The project was completed in 2017.
Requirement
Floor height of the Ground Floor is 24’7” while that of the above floors is 16’. Foyer on the ground floor (48’7” x 56’3”) required a clear headroom space while rooms were to be made on the above floors for which floating columns were provided.
Solution
In order to provide a clear column-free interior space for foyer, four post tensioned girder beams of span 48’3” are provided parallel to each other which bear the overall loading of above floors through floating columns. Monostrand Unbonded Post-tensioning System has been adopted. The depth of these beams was 54”.
The girder beams provided are designed to resist the loads from all above seven floors. Also, stressing for P-T Beams was done in stages. Cables were stressed up to half pressure after achieving concrete strength of 25 N/mm2. After constructing 3 floors and before casting of 4th floor, full stressing was applied in cables of other floors.
Unbonded Post-Tensioning System was a preferred solution over Bonded Post-Tensoning System in this case as execution required stage stressing. As per Indian Standard Code of Practices, grouting shall be carried out as early as possible but not later than 14 days of stressing of tendons. This stipulation could not be followed here as it could induce corrosion related issues.
