Hi
I am relatively new to ASBD (I'm using 2024 version) and trying to do a PSC plank (pretension) beam design. Its an integral bridge (9m span) and the beam(composite action with deck) is integrated into the abutment beam. Can you please provide guidance on the below modeling queries/techniques. Attached file for your reference.
1) The PSC beam when cast and prestressed, considering 100 days before its integration with the abutment will have simply supported boundary conditions. Lets call this stage 1. At stage 1, only SW and prestress force is acting. Temp loading also (for creep and shrinkage)
After 100 days when the abutment head is cast and the beam is integrated with the abutment (stage 2), the boundary conditions change into fixed and then the beam will be subjected to loads during service -SIDL (wearing course), SDL(barrier), Live loads, temp loading etc.
How do i define and activate the stages of these loading with their respective boundary conditions?
2) Another query related to above is for application of loading. Currently whatever max sagging BM i have for a given load say LL=75kNm for span=9m, i have converted it into a UDL for a simply supported=8*M/L^2.
so my UDL becomes = 8*75/(9^2)= 7.41 kN/m.
But during service, as its an integral bridge, the boundary conditions change to fixed and i have hogging moments (max 130kNm) as well in addition to the sagging moment (75kNm)
How should the loads be applied in such case to get the expected behavior.
3) I have calculated the shrinkage and creep for
- PSC beam at 100 days (only beam is cast)
- PSC beam for 100 years (whole structure is cast, design life)
- composite (beam/deck) for 100 years (whole structure is cast, design life)
In help I couldnt find. what does 'default' mean correspond to? As in what stage? I have assumed it to be for the final composite design life stage (100 years) only since rest of the coefficients are being filled for design life (100 years). Please correct me if I'm wrong.
Looking forward to your response. Please also advise if there's any further modeling ways that can be implemented here for better results. Attached file for your reference. Thanks
