Post on 13-Apr-2018
transcript
7/27/2019 Prestressed Girder Design_Roof Deck by Frame
1/93
Girder Properties
m
mm
mm
MPaMPa m
kN
mm
mm mm
STAAD Values
kN-m (End) mm mm
kN-m (Mid)
kN-m (End) nAps
kN-m (Mid) mm mm
kN-m (End)
Solution
For Tendon Area: | For N.A. and e: | a 1) @ Top (Midspan):
| | -Pi
| | Ag
| |
| |
| nAps= mm2 |
| |
| bh(h/2)+nApsdp |
| | b 1) @ Bottom (Midspan):
Area mm2 | | -Pi
| | Ag
| || Yb= h - Yt |
| Yb= mm = |
| |
| e= dp - Yt |
| e= mm | a2) @ Top (End):
mm | | Pi
(7-Strand) | For Ig about N.A.: | Ag
Therefore, Use | |
| |
| Ig= mm4 |
| |
Actual Tendon Area: | |
Npsx Nominal Area | | a2) @ Bottom (End):
mm2 | Moments due to Beam Wtg. | Pi
| Wo=conc X bh= kN/m | Ag
| |
| |
Apsx 0.7fpu | |
kN | |MPa (T)
Pi = 630.7515 24
2.83212
Pi =Mmid =
WOL2
= 25.5 kN-m f2= 2.89849
kN-m f2= 3.5042 - 3.4377 +
-MoYb
4.25 Ig Ig
Actual Prestressing
Force:Mend =
WOL2
= 51
0.70777 MPa (T)
Stresses @ initial
applied service Beam WgtAps =
Aps = 523.88f2= +
PieYb
2 - 7.94mm dia. 7-Wire
Strands 5434154831f1=
f1= 3.5042 + 3.3945 - 2.7964
f1= -PieYt
+MoYt
Nps = 2 Ig Ig
15.24 139.35 0.537065
98.1025
dps = 7.94
-5.5004 MPa (C)12.7 92.9 0.805597
11.11 69.68 1.074053 298.103 Yt @ Endf2=
3.3945 + 1.39829.53 51.61 1.4501077.94 37.42 2 f2= -3.504 -
f2= -PieYb
+MoYb
6.35 23.22 3.223084 Ig Ig
bh + nAps
Dia. mmYt= 301.897 mm= Yb @ End
# of 7-Wire Strand (ASTM
A 416):Yt= =
Nominal Nominal # 7-Wire
Strand
3.4377 - 1.416
3481.55f1= -1.4825 MPa (C)
Use Uncoated Seven-Wire
Stress-Relieved (Grade
250)
n= 6.65 f1= -3.504 +
-MoYt
0.7fpu Econcrete 4700f'c Ig Ig
Esteel=
200000 MPaf1= +
PieYt
MEL= 173.5 Fig. Cross-Section(@ Midspan)
Fig. Cross-Section
(@ End)
Aps=Pi
= 523.9 mm2 n=
600
-161
MLL =58.42 Beam #:
-39.6 149 300 300
em = 100 e = 100
400 mm
MDL =288 600
12
Pi = 630.8 Fig. Tendon Profile
ee = 100 Allowable (e)
b = 300
f'c = 41fpu = 1720
Design of Prestressed GirdersFrame A (Roof Deck) Critical Girder
L = 12
h = 600
A
yA
2
ps
2
t
3
g enA
2
hYbh
12
bhI
7/27/2019 Prestressed Girder Design_Roof Deck by Frame
2/93
| a 1) @ TOP (Midspan): | a2) @ Top (End):
| -Pe | Pe
| Ag | Ag
| |
Where: | |
Pe= 0.8Pi = kN | |
kN-m (End) | |
kN-m (Mid) | |
kN-m (End) | b 1) @ Bottom (Midspan): | b1) @ Bottom (End):
kN-m (Mid) | -Pe | Pe
kN-m (End) | Ag | Ag
| |
| |
| |
| |
|
|
|
f1= < | f1 | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | |
| |
| | < L/250
| | Downward
| |
| || Deflection Check | < L/300 Upward
@ END SPAN of the Beam | |
| Deflection from (STAAD) | Checking
> | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward | | Due to Prestressing Force Pi | < L/300
| Pi = mmUpward |