asixth
Structural
- Feb 27, 2008
- 1,333
Hi guys,
I am currently designing a prestressed bridge girder for my department of transport and I am required to provide calculated hogs at transfer and also 28 days.
This girder is to be strength 40MPa (5800psi) at transfer, is 1100mm deep (4') and is pretensioned to 4400kN (1000kips).
I have calculated the hog at transfer to be 30mm (1.25"). I calculated this using Igross and the Youngs modulus based on the code I am using. I performed a linear elastic analysis.
Now, I am guessing that the girder should continue to hog to approximatley 45-50mm by 28 days due to creep and shrinkage. But how do I calculate the additional rotations and deflections due to creep and shrinkage?
Any thoughts will be appreciated.
I am currently designing a prestressed bridge girder for my department of transport and I am required to provide calculated hogs at transfer and also 28 days.
This girder is to be strength 40MPa (5800psi) at transfer, is 1100mm deep (4') and is pretensioned to 4400kN (1000kips).
I have calculated the hog at transfer to be 30mm (1.25"). I calculated this using Igross and the Youngs modulus based on the code I am using. I performed a linear elastic analysis.
Now, I am guessing that the girder should continue to hog to approximatley 45-50mm by 28 days due to creep and shrinkage. But how do I calculate the additional rotations and deflections due to creep and shrinkage?
Any thoughts will be appreciated.
