Go through the following construction video that shows how to develop a prestressed concrete unit (Double T) on a prestressing concrete plant.
Double T is a multipurpose prestressing unit usually applied in parking structures but also be utilized in various buildings together with office buildings, industrial buildings etc. The Double Ts contain the potentiality of supporting span extending to 60ft as well as upto 120ft.
The initial step is to set up the necessary forms (here double T) as soon as the cleaning is completed. Under this construction video, a bed is arranged for 5 double T units having length 60ft long. Self stressing form is ideal for prestressing which can deal with prestressing compression force as well as the eccentricity of the strands.
The crew members can arrange strands in the form and transit them through prestressing plate. Strands are placed constantly over 5 units and later on segregated with the space provided by the dividers.
Strands already set in 2nd step are then tensioned to about 2 to 5 kips on the basis of gauge pressure reading. Here a mark is given on strands once the preload is applied. The strands are then tensioned and noted through gauge pressure on hydraulic pump. Quality control Technician then verifies elongation of strands against theoretical elongation. It necessitates that force on gauge and elongation measured should be equal with 5% tolerance limit. If it fails then strand should have been detensioned and then tensioned again.
For more information visit this link.