COMMON DESIGN MISTAKES IN POST-TENSIONED CONCRETE
COMMON DESIGN MISTAKES IN POST-TENSIONED CONCRETE.
1- do not consider long-term defections cracked.
Beams and penetrant slabs have an inherent advantage over their limbs relative to their limbs with respect to deflection.
2- use of the supplement bar for reinforcing retraction and temperature in parking garage slabs.
3- negotiate to design any general anchoring area or to disclaim this liability.
The PT suppliers are responsible for the design of the local anchorage areas and many engineers mistakenly believe that they will also look after the general area.
4- sweeping tendons to low points without appropriate detail. If it is necessary to scan the tendons laterally - and often this will be the result of misaligned columns - be sure to properly detail these areas, either at the bottom or at any other point on the slab.
5- Ignore the effect of the slabs on the tendon profile.
6- over balancing the dead load in your designs.
7- confidence with 3d software finite element for design and drawings.
8- bad specifications for tendon finishing and inspection.
9- specification failure of encapsulated systems: PT encapsulated systems must be specified on all PT buildings (with the possible exception of floor slab construction).
10- ignoring the content of shortening effects : This is the source of most of the problems associated with new designs, both aesthetic and structural.
It is essential to evaluate the design in terms of the potential for stress and to include measures to mitigate these effects.
Post tension slab step by step process
1- do not consider long-term defections cracked.
Beams and penetrant slabs have an inherent advantage over their limbs relative to their limbs with respect to deflection.
2- use of the supplement bar for reinforcing retraction and temperature in parking garage slabs.
3- negotiate to design any general anchoring area or to disclaim this liability.
The PT suppliers are responsible for the design of the local anchorage areas and many engineers mistakenly believe that they will also look after the general area.
4- sweeping tendons to low points without appropriate detail. If it is necessary to scan the tendons laterally - and often this will be the result of misaligned columns - be sure to properly detail these areas, either at the bottom or at any other point on the slab.
6- over balancing the dead load in your designs.
7- confidence with 3d software finite element for design and drawings.
8- bad specifications for tendon finishing and inspection.
9- specification failure of encapsulated systems: PT encapsulated systems must be specified on all PT buildings (with the possible exception of floor slab construction).
10- ignoring the content of shortening effects : This is the source of most of the problems associated with new designs, both aesthetic and structural.
It is essential to evaluate the design in terms of the potential for stress and to include measures to mitigate these effects.
Post tension slab step by step process
