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Pretensioned Beam Deformation

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JohnRwals

Structural
Joined
Jul 8, 2020
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156
Location
US
Hello!
In order to check connection details during erection stage in the precast concrete beams,
I am looking for a book or papers explaining how to predict section behaviors after prestressing force is applied.
I am interested in horizontal deformation rather than vertical deflections/cambers.

Thanks!
_JRW
Prestressed_Beam_z3gpkd.jpg
 

This is a useful document.

The shortening of the beam due to the prestressing force will have occurred before the erection stage and will be accounted for in manufacture.

Screenshot_2024-05-21_100110_utytyw.png


The image above gives the maximum tolerances on length deviations in the British standards but a typical tolerance might be +-10mm

Any further shortening due to camber will be very small and can probably be ignored. The bearing length of the unit will be enough.

The TLDR for predicting long term deformation due to prestress is that it is very difficult and can't really be done accurately.
 
Determine the average compression stress in the bottom face, under the load and prestress at the time, over the length of the beam and multiply by L / Ec.trans
 
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