Relaksasi baja TEORI DASAR

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 ⋅ =