Precast Units Stressed Separately
Before breaking up precast units stressed separately from the main frames of the structure, they should be lowered to the ground, if possible.
This is an example of a precast and pre-stressed concrete bridge.
It is advisable to seek the counsel of a professional engineer before carrying out this work, especially where there are ungrouted tendons. In general, this is true because grouting is not always 100% efficient.
- After lowering, the units can be turned on their side with the ends up on blocks after any composite concrete is removed. This may suffice to break the unit and release the prestress; if not, erect a sand bag screen, timbers, or a blast mat as a screen around the ends.
- Clear the area of any personnel.
- Remember the end blocks may be heavily reinforced and difficult to break up.
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4-5. What should you do before breaking up precast units stressed separately from the main frames of the structure?
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