Tugas 3a.xlsx

Data Perencanaan L = Wl = WSD = WD = f'c =

75 ft 1200 plf 360 plf 1059.09 kg/m 6000 psi

=

22.875 m

Konversi : 1 1 1 1 1

f'ci

=

4500 psi

1

fpu

=

270000 psi

1

fpi

= = = = = = = = = =

fpy

t ec RH V/S Ac1 = Ac3

0,70 x fpu 0,70 x 270.000 189000 psi 0,85 x fpu 0,85 x 270.000 229500 psi 5 tahun 19 in 75 3 in

=

480 in2

Ac2

=

204 in2

Actotal

=

684 in2

Ic MD

=

233892 in4

Eps Eci

Ec

= = = = = = = = = =

1/8 x q x L2 1/8 x 1.059.09 x 22.88^2 69273.47838825 kgm 28000000 psi 57000 x √f'ci 57000 x √4.500 3823676.24152464 psi 57000 x √f'c 57000 x √6.000 4415201.01467646 psi

=

43800 jam

=

0.44 m2

=

6012245.18932 lb.in

Tahap sebelum transfer a. Perpendekan elastis Pi = Aps x fpi = 12 x 0,153 x 189.000 = 578340 lb -Pi/Ac - (Pi x e x e / Ix) + (MD x e/Ic) fcs = = -578.340 / 684 - (578.340 x 19 x 19 / 233.892) x (6.012.245.19 x 19 / 233.892) = -1249.7645 psi n = Eps / Eci = 28.000.000 / 3.823.676.24

1 1 1 1 1 1 1 1

Δfpes

= = = =

7.3228 n x fcs 7.32 x 1.249.76 9151.7702522557 psi

Tahap sesudah transfer a. Kehilangan karena rangkak fcs = MSD =

fcsd

Kcr Δfpcr

= = = = = = = = =

1249.7645 psi 1/8 x q x L2 1/8 x 360 x 75^2 253125 lb.ft MSD x e / Ic

=

3.037.500 x 19 / 233.892 246.7484993074 psi 2 (beton normal) n x Kcr (fcs - fcsd) 7.32 x 2 x (1.249.76 - 246.75) 14689.7627973007 psi

b. Kehilangan karena susut KSH = V/S RH EPS

= = =

Δfpsh

= = =

3037500 lb.in

1 (komponen struktur pratarik) 3 in 75 28000000 psi -6 8.2 x 10 x KSH x EPS (1-0.06V/S) (100-RH) 8.2 x 10^-6 x 1 x 28.000.000 x (1-0.06 x 3) x (100-75) 4706.8 psi

c. Relaksasi tendon (relaksasi tegangan baja) fpy = 229500 psi f'pi = 160650 psi t = 43800 jam Δfpr = f'pi x (logt/10) x (f'pi/fpy - 0,55) = 160.650 x (log 43.800 / 10) x (160.650 / 229.500 - 0.55) = 11184.7922 psi

Konversi : ft in in psi plf

= = = = =

0.305 m 25.4 mm 2.54 cm 0.00689 Mpa 0.01459 kN/m

in2

=

6.4516 cm2

in3

=

16.387064 cm3

in4 kg/m kN-m lb-in kN-m lb-in kg.m lb.ft

= = = = = = = =

41.6231426 cm4 0.0098 kN/m 8850.7457 lb-in 0.000112 kN-m 101.972 kg-m 12 plf 86.79 lb.in 12 lb.in

Level tegangan pada berbagai tahap Sesudah penarikan (0.7 x fpu)

Teg. Baja (psi) 189000

Persen 100

Perpendekan elastis

-9151.77025226 -4.842206

Rangkak

-14689.7627973 -7.772361

Susut Relaksasi Tegangan netto akhir fpe Presentase kehilangan total

-4706.8 -2.49037 -11184.7922 -5.917879 149266.87 78.98 21.02