Strengthening of PEB Beam with External Post-Tensioning

Location: Vadodara, Gujarat
About Project
It is an Industrial Pharmaceutical Unit, project located in outskirts of Vadodara. The plant was constructed in PEB with steel structural members.
Requirement
Members in the PEB completely executed, experiencing deflection beyond the limits. Hence some external mechanism is required to control further deflections in long-term. The span of the PEB Beam is around 17m and deflection was excessive.
Solution
We were approached by the Structural Consultant to work out some solution for an existing building recently completed and commissioned in a pharmaceutical plant. The building was constructed in PEB with steel structural members. Ground floor to be used for Storage of finished material and first floor to be used for testing laboratory. The building was under operation for some time. The Ceiling of ground floor was observed deformed excess than the limits of visual perception. Hence, we were consulted by the Structural Consultant for the treatment solution. There was a constraint that the floor must not get adverse effects of lifting force generated from the Post-Tensioned cables. We proposed external Post-Tensioning as it was existing structure having enough strong elements at the ends where the forces is expected to be applied through anchorage. The work has been carried out successfully in such a way that there was no uplift deformation of the PEB Girders during transfer of the prestress force while stressing and hence the arrangement of the Testing Laboratory did not get disturbed adversely by the uplift effects. The PEB girder is now sufficiently strengthened against long-term deflection as well as having more residual strength and redundant capacity than before its retrofitting.
