1 Introduction
1.1 AASHTO Approach
1.2 Dischinger Method
1.3 ACI 209 Method
Cement type | Curing | Duration | ||
---|---|---|---|---|
I | III | ts (days) | ||
Strength | ||||
a
| 4.0 | 2.3 | Moist | |
1.0 | 0.7 | Steam | ||
β | 0.85 | 0.92 | Moist | |
0.95 | 0.98 | Steam |
1.4 The CEB-FIP Method
2 PSTRS14 Software
3 Sample Bridge Description
3.1 PSTRS14 Software Input
Girder data | Ext. Tx-40 | Int. Tx-40 | Ext. Tx-54 | Int. Tx-54 |
---|---|---|---|---|
C/C bearing length (m) | 26.8 | 26.8 | 36.0 | 36.0 |
Beam spacing (m) | 2.1 | 2.4 | 2.1 | 2.4 |
Moment LL dist. factor | 0.585 | 0.643 | 0.579 | 0.636 |
Shear LL dist. factor | 0.743 | 0.814 | 0.743 | 0.814 |
4 Moe Analysis and Results
t
final
(days) | Description |
---|---|
2 | Initial stress transfer |
10 | Girder curing |
14 | Girder placement at jobsite |
104 | Casting of deck on girders |
134 | Casting of railing |
254 | Bridge opening to traffic |
365 | At 1 year |
730 | At 2 years |
t
final
(days) | Creep coefficient, ψ [Eq. (9)] | ||
---|---|---|---|
2 | 0.149 | 0.04 | 1,404 |
10 | 0.169 | 0.15 | 3,200 |
14 | 0.178 | 0.18 | 3,522 |
104 | 0.327 | 0.66 | 4,502 |
134 | 0.360 | 0.77 | 4,546 |
254 | 0.451 | 1.08 | 4,620 |
365 | 0.502 | 1.27 | 4,646 |
730 | 0.586 | 1.60 | 4,676 |
4.1 Effects of Variable MOE on Prestress Losses During Construction
Load | Exterior girder | Interior girder |
---|---|---|
Due to overlay | 260 | 298 |
Due to railing | 155 | 155 |