Hi everyone,
Reference AASHTO clause 5.8.3.6.3 (longitudinal reinforcement) for torsion:
AASHTO 2014 suggest to include portion of longitudinal PT as part of this longitudinal reinforcement requirement. Just want to know if anyone has ever used long PT in the calculations and how?
see attached...
Can anyone advise any references about procedure of conducting a friction test to confirm friction coefficient value i.e. friction between tendon and duct?
This is required to confirm the actual tendon elongation values.
Thanks
KootK,
In my case, the duct size is not excessively large and therefore it is not the reason. The grouting was done after the application of force.
With this clause,I was thinking that the behavior of prestressed member as compared to that of column or other compression members is different...
I think this ACI 318-14 R9.2.3.2 clause is quite related to this issue:
If the duct size is not excessively larger than the prestressed reinforcement, the axial prestress force cannot buckle the member.
KootK
Yes you are correct, it should not happen if there is no lateral eccentricity.
The fact that large sweep values are observed after release of the force which indicates one of the following and these could not be verified as far as i know:
1-lateral eccentricity of the tendons;
2-casting...
KootK
Yes I agree with your point, but I believe there will be no bending if tendons has zero eccentricity? even the girder is slender.
Ingenuity
I did not find any reference for slenderness criteria to be used for precast prestressed beams. I mean is there any slenderness ratio criteria based...
Thank you all for the useful feedback.
Let me add some info which may be helpful in the discussion and might answer your comments as well:
The precast girder is a 41m long, 2.1m deep and yes it is post tensioned with 3 tendons. After the release of the prestress force while the girder remains...
Hi all,
What are the potential causes if a precast prestressed (post tensioned) I-girder slender beam deforms in the lateral direction after release of the prestress force:
I know some of the reasons are:
eccentric tendons in the lateral direction;
imperfections in the casting of girder...
