197
Tabel 5.28 Tabel Kehilangan Tegangan Beton
∆fci 1,16
∆fsh 0,96
∆fcr 0,98
Baja ∆frel
3,07 ∆f
AS
2,71 f
B
3,7 Total Kehilangan Tegangan
12,58 R = 100 - 12,58 = 87,42
5.5.7 Gaya Prategang Efektif
- Kondisi transfer : P = 726,939 ton = 726939 kg
Asp = Jumlah Strand x Luas Kabel Prestress Ast = 51 x 0,9871
= 50,342 cm
2
Tegangan Kabel = P Asp = 726939 50,342
= 14440 kgcm
2
q- balance Tinjauan Tengah Bentang = qb = -P x e x 8 L2 = - 726,939 x 0,684 x 8 30
2
= - 4,419 t m - Kondisi Servis :
P = 87,42 x 726,939 ton = 635,5 ton = 635500 kg Asp = Jumlah Strand x Luas Kabel Prestress Ast
= 51 x 0,9871 = 50,342 cm
2
Tegangan Kabel = P Asp = 635500 50,342
= 12623,62 kgcm
2
q- balance Tinjauan Tengah Bentang = qb = -P x e x 8 L2 = - 635,5 x 0,934 x 8 30
2
= - 5,276 t m
198
5.5.8 Kontrol Tegangan
A. Kontrol Tegangan Saat Transfer Tinjauan Tengah Bentang Momen
DL
Girder
= 18869100 kg m Momen
Balance =
2
8 1
L qb
=
2
30 419
, 4
8 1
− = -497,109 ton m = -49710900 kg cm
Momen Net- = Momen DL
girder
+ Momen Balance = 18869100 + -49710900
= -30841900 kg cm Akibat Pi axial tekan = Pi A
= 726939 6709 = 108,353 kgcm
2
Akibat momen ; Untuk serat atas = M
Net
S
a
= -30841900 269252.151 = - 114,546 kgcm
2
Untuk serat bawah = M
Net
S
b
= -30841900 290087.176 = 106,319 kgcm
2
Tegangan transfer : ftop =
a c
i
S Mnet
A P +
= 108,353 + - 114,546 = - 6,193 kgcm
2
tarik ≤ - 12,33 kgcm
2
tarik Aman fbot
=
b c
i
S Mnet
A P +
= 108,353 + 106,319 = 214,672 kgcm
2
tekan ≤ 365,057 kgcm
2
tekan Aman
199
B. Kontrol Tegangan Saat Servis Tinjauan Tengah Bentang Momen
DL
Total
= 38867800 kg m Momen
Balance =
2
8 1
L qb
=
2
30 276
, 5
8 1
− = - 593,534 ton m = - 59353400 kg cm
Momen Net- M
1
= Momen DL
Total
+ Momen Balance = 38867800 + -59353400
= -20485600 kg cm Momen
LL
Total
M
2
= 22908300 kg cm Akibat
Pi
eff
axial tekan = Pi
eff
A = 635500 6709
= 94,723 kgcm
2
Akibat momen M
1
; Untuk serat atas
= M
Net
S
a
= -20485600 269252.151 = - 76,083 kgcm
2
Untuk serat bawah = -M
Net
S
b
= - -20485600 290087.176 = 42,281 kgcm
2
Akibat momen M
2
; Untuk serat atas
= M
2
S
ac2
= 22908300 637948.283 = 35,909 kgcm
2
Untuk serat bawah = -M
2
S
bc
= - 22908300 377070.689 = - 60,753 kgcm
2
Tegangan transfer
: Slab = M
2
S
ac1
= 22908300 484509.604
200
= 47,281 kgcm
2
tekan ≤ 350 kgcm
2
tekan Aman ftop
=
2
2
ac a
c ieff
S M
S Mnet
A P
+ +
= 94,723 + - 76,083 + 35,909 = 54,549 kgcm
2
tekan ≤ 325,944 kgcm
2
tekan Aman fbot
=
bc a
c ieff
S M
S Mnet
A P
2 +
+ = 94,723 + 42,281 – 60,753
= 76,251 kgcm
2
tekan ≤ -13,46 kgcm
2
tarik Aman
5.5.9 Perhitungan Lendutan
