c. Tulangan Baja
Wiremesh
fy 390 Mpa
⋅ =
BJTP Polos
fyp 240 Mpa
⋅ =
fyd 390 Mpa
⋅ =
BJTD DeformUlir
3. Dimensi Pelat dan Komposit Dimensi Pelat
Tinggi pelat
hsl htop
h +
= hsl
250 mm ⋅
=
Panjang Total
Lsl 6.0 m
⋅ =
Tinggi topping
htop 50 mm
⋅ =
Penampang Komposit
fkubtop 225 kgf
⋅ cm
2 −
⋅ =
beton Topping mutu beton K-225
fctop 0.83 fkubtop
⋅ =
fctop 18.675 Mpa
⋅ =
Ectop 4700
fctop Mpa ⋅
⋅ =
Ectop 20310.853 Mpa
⋅ =
nc Ectop
Ec =
nc 0.75
=
Lebar pelat
bw 1200 mm
⋅ =
be 900 mm
⋅ =
Lebar pelat tranformasi
be nc bw
⋅ =
Ack 1.48
10 5
× mm
2 ⋅
=
Luas Penampang
Ack Ac
be htop ⋅
+ =
Cbk be htop
⋅ h
htop 2
+
⎛⎜ ⎝
⎞⎟ ⎠
⋅ Ac Cb
⋅ +
Ack =
Garis Berat Bawah
Cbk 138.007 mm
⋅ =
Garis Berat Atas
Ctk hsl
Cbk −
= Ctk
111.993 mm ⋅
= I ck
I c Ac Cbk
Cb −
2 ⋅
+ be htop
3 ⋅
12 +
be htop ⋅
Ctk htop
2 −
⎛⎜ ⎝
⎞⎟ ⎠
2 ⋅
+ =
Momen inersia
I ck 1.075
10 9
× mm
4 ⋅
= Stk
I ck Ctk
= Stk
9597114.63 mm 3
⋅ =
Sec. Modulus Top
Sbk I ck
Cbk =
Sbk 7788111.383 mm
3 ⋅
=
Sec. Modulus Bottom
4. Perhitungan gaya dalam
γ c
24 kN ⋅
m 3
− ⋅
=
Berat volum beton normal Faktor Reduksi Lentur
φ 0.9
= Qslb
2.472 kN m 1
− ⋅
⋅ =
DL : Pelat
Qslb Ac
γ c
⋅ =
Mslb 1
8 Qslb
⋅ Lsl
2 ⋅
= Mslb
11.124 kN m ⋅
⋅ =
Qtop 1.44 kN m
1 −
⋅ ⋅
=
Topping
Qtop htop bw
⋅ γ
c ⋅
= Qtam
100 kgf ⋅
m 1
− ⋅
= 1
− Qtam
1 kN m 1
− ⋅
⋅ =
tambahan
Qsdl 100 kgf
⋅ m
⋅ =
SDL : 64
Qll 300 kgf
⋅ m
1 −
⋅ =
Qll 3 kN m
1 −
⋅ ⋅
=
B. Hidup LL :
Momen
Pada saat pengecoran topping HCS diberi tumpuan sementara ditengah bentang
Qd2 2.44 kN m
1 −
⋅ ⋅
= Qd2
Qtop Qtam
+ =
Mdx x 3
16 Qd2
⋅ Lsl
⋅ x
⋅ 1
2 Qd2
⋅ x
2 ⋅
− =
Mdx 0.5 Lsl ⋅
2.745 −
kN m ⋅
⋅ =
Mcorpek Mdx 0.5 Lsl
⋅ −
=
negatif Pada saat tumpuan sementara dilepas
P 5
8 Qtop
⋅ Lsl
⋅ =
P 5.4 kN
⋅ =
Mprop 1
4 P
⋅ Lsl
⋅ =
Mprop 8.1 kN m
⋅ ⋅
= Mll
1 14
Qll ⋅
Lsl 2
⋅ =
Mll 7.714 kN m
⋅ ⋅
= Msdl
1 14
Qsdl ⋅
Lsl 2
⋅ =
Msdl 2.571 kN m
⋅ ⋅
= Mts
Mslb Mcorpek
− Mprop
+ Mll
+ Msdl
+ =
Mts 26.765 kN m
⋅ ⋅
= Mu
1.2Mslb 1.2Mcorpek
− 1.2Mprop
+ 1.2 Msdl
⋅ +
1.6Mll +
= Mu
35.203 kN m ⋅
⋅ =
Jadi banyaknya tendon
n 5
= Aps
141.372 mm 2
⋅ =
Luas Total Prestress
Aps n A1
⋅ =
Hasilnya :
Pi Aps fpi
⋅ =
Pi 137.837 kN
⋅ =
5. Check Tegangan
Peff fpeff Aps
⋅ =
Peff 110.27 kN
⋅ =
fpi 975 Mpa
⋅ =
Pi fpi Aps
⋅ =
Pi 137.837 kN
⋅ =
a. Pada saat transfer HCS saja:
σ a1l
Pi −
Ac Pi e
⋅ St
+ =
Fti 1.161 Mpa
⋅ =
≤
σ a1l
0.576 Mpa ⋅
= σ
b1l Pi
− Ac
Pi e ⋅
Sb −
=
≤
Fci 12.948
− Mpa
⋅ =
σ b1l
3.252 −
Mpa ⋅
=
b. Pada saat setelah losses
σ a1l
Peff −
Ac Peff e
⋅ St
+ Mslb
St −
= Fc
14.94 −
Mpa ⋅
=
≤
σ a1l
1.47 −
Mpa ⋅
= Ft
2.881 Mpa ⋅
= σ
b1l Peff
− Ac
Peff e ⋅
Sb −
Mslb Sb
+ =
≤
65
σ b1l
0.671 −
Mpa ⋅
=