Beton : K-400 Kabel Prategang

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 ⋅ = Tegangan setelah topping terpasang σ a2l σ a1l Mcorpek St + = Ft 2.881 Mpa ⋅ = ≤ σ a2l 0.994 − Mpa ⋅ = Fc 14.94 − Mpa ⋅ = σ b2l σ b1l Mcorpek Sb − = ≤ σ b2l 1.147 − Mpa ⋅ = Tegangan setelah prop dilepaskan Sebagai pelat komposit σ a3l σ a2l Mprop h Cbk − ⋅ I ck − = σ a3l 1.461 − Mpa ⋅ = Fc 14.94 − Mpa ⋅ = ≤ σ b3l σ b2l Mprop Sbk + = σ b3l 0.107 − Mpa ⋅ = Ft 2.881 Mpa ⋅ = ≤ c. Pada saat beban layan bekerja Sebagai pelat komposit σ a4l σ a3l Mll Msdl + h Cbk − I ck ⋅ − = σ a4l 2.054 − Mpa ⋅ = ≤ Fc 14.94 − Mpa ⋅ = σ b4l σ b3l Mll Sbk + Msdl Sbk + = σ b4l 1.213 Mpa ⋅ = Ft 2.881 Mpa ⋅ = ≤ Tegangan_beton_Saat_Layan MEMENUHI =

6. Check Kapasitas Momen

Dw 6 mm ⋅ = Diameter Tulangan Pratekan Dw Dia = Diameter tulangan Ds 6 mm ⋅ = As1 1 4 π ⋅ Ds 2 ⋅ = As1 28.274 mm 2 ⋅ = Luas per tulangan Banyaknya tul. tekan nc = Asc 0 mm 2 ⋅ = Luas Total tul. tekan Asc nc As1 ⋅ = Banyaknya tul. tarik np = Ast 0 mm 2 ⋅ = Luas Total tul. tarik Ast np As1 ⋅ = Selimut Beton dc 20 mm ⋅ = Lengan Tulangan Pratekan dp Ct e + = dp 180 mm ⋅ = d 221 mm ⋅ = Lengan Tulangan Non Pratekan d hsl dc − Dw − 0.5 Ds ⋅ − = fpe Peff Aps = Tegangan Tul. Pratekan Efektif ≥ fpe 780 Mpa ⋅ = 0.5 fpu ⋅ 812.5 Mpa ⋅ = maka : Nilai untuk p : 66 fpy fpu 0.9 = γ p 0.2 8 =