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PONDASI DANGKAL MEKANIKA TANAH II YULVI ZAIKA. Powerpoint Templates. KEDALAMAN TANAH KERAS BEBAN YANG DITAHAN BIAYA YANG TERSEDIA PENGARUH-PENGARUH LAIN. SYARAT- SYARAT PEMILIHAN PONDASI. Lapisan Tanah Keras. PONDASI TELAPAK. property line. property line. P1. P2. P 1. P2.

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  1. PONDASI DANGKAL MEKANIKA TANAH II YULVI ZAIKA Powerpoint Templates

  2. KEDALAMAN TANAH KERAS BEBAN YANG DITAHAN BIAYA YANG TERSEDIA PENGARUH-PENGARUH LAIN SYARAT- SYARAT PEMILIHAN PONDASI

  3. Lapisan Tanah Keras PONDASI TELAPAK

  4. property line property line P1 P2 P1 P2 2 footings close to each other P1 close to property line and P2 > P1 If 1/2 < P2/P1 < 1 use trapezoidal footing property line If P2/P1 < 1/2, use strap combined footing Combined footing

  5. BENTUK PONDASI TELAPAK

  6. PONDASI TELAPAK MENERUS/ LAJUR

  7. PONDASI RAKIT

  8. PONDASI RAKIT

  9. PONDASI RAKIT

  10. Kedalaman tanah pondasi kurang atau sama dengan lebarnya atau kedalaman (Terzaghi, 1943). Teori lain, kedalaman pondasi dangkal 3-4 kali lebar pondasi. Pondasi setempat harus memenuhi syarat-syarat: Stabilitas, aman terhadap keruntuhan geser deformasi harus lebih kecil dari yang diizinkan. Df Lapisan Tanah Keras B SYARAT PONDASI DANGKAL

  11. METODA PELAKSANAAN

  12. KERUNTUHAN PADA PONDASI DANGKALPADA TANAH PASIR PADAT DAN LEMPUNG KAKU B

  13. keruntuhanumumgeser pasirpadat Dr>67% lempungkaku NSPT >12 Koruntuhanlokal pasiratau pasirkelempungan kurangpadat (medium) 30%<Dr<67% Keruntuhanpenetrasi Pasirlepas Dr< 30% Beban/luas qu Penurunan Permukaanruntuh Beban/luas (a) qu1 qu Permukaan runtuh Penurunan (b) Beban/luas qu1 qu qu Permukaan runtuh Penurunan (c) MODEL KERUNTUHAN GESER

  14. MODEL KERUNTUHAN BERDASARKAN RELATIF DENSITY

  15. Terzaghi Assumptions • 1.    Soil under footing is homogeneous and isotropic  • 2. Soil surface is horizontally • 3. The base of footing is rough, to prevent the shear displacement. • 4      The foot is shallow foundation, i.e. the depth of foundation is less than the width of foot… • Df      ≤        B • 3.     Shear strength above the level of the base of footing is negligible. c = 0 above ( F.L ). • 4.     Consider only the surcharge which produced as uniform pressure      •    q = DF at foundation level. • 5.      The load on foundation is vertical and uniform. • 6.     The foot is long strip footing (pondasilajur, B/L  0). • 7.  = 

  16. Shear failure happened on many stages • I) Stage I: The soil in the elastic case and behave as the part of foundation it still that, and by increasing the load performed the region I which called active zone. • II)     Stage II: At this stage the foundation load effect on the active zone and neighboring soil so perform the region which called arc of logarithmic spiral zone. • III)    Stage III: By increasing the load performed the third part curve in which part the soil became in the passive case it make to resist the failure.

  17. PROSES TERJADINYA KERUNTUHAN

  18. Three components produced to resist the failure of soil. I)  (Pp)γ   = Component produced by the weight of shear zone II, III. II)(Pp)c = Component produced by the cohesive stress. III) (Pp)q = Component produced by the surcharge q. Pp     = (Pp)γ + (Pp)c + (Pp)q

  19. DASAR PENURUNAN RUMUS TERZAGHI • Kesetimbangan Gaya qu(2b)= -W+ 2Pp+f sin f • W=(1/2)2bgbtana=b2gtanf • f=c DC= c. b/cosf • Pp=(1/2)g (b tan f)2 Kg + c (b tan f)Kc +q(b tan f) Kq • qu =c{tan f (Kc +1)} +q(tan f Kq) + g B/2{(1/2) tan f(Kg. tan f-1)} B=2b qu A B   f Zonapasif f W   Zonaaktif Zonageser radial Pp Pp J

  20. PERSAMAAN DAYA DUKUNG TERZAGHIUNTUK PONDASI LAJUR/ MENERUS Nq = = e Nc =

  21. Daya dukung: Pondasi lajur Pondasi bujursangkar Pondasi lingkaran Untuk keruntuhan geser lokal: c’ = 2/3 c dan f’ = 2/3f B J I q=gDf Df qu 45-f/2 45-f/2 H a a 45-f/2 45-f/2 A G C E F D TEORI DAYA DUKUNG TERZAGHI (1943)

  22. GRAFIK FAKTOR DAYA DUKUNG Local shear failure General shear failure

  23. PERBANDINGAN BIDANG RUNTUH

  24. Fcs , Fqs , Fs = faktorbentuk Fcd , Fqd , Fd= faktorkedalaman Fci , Fqi , Fi = faktorinklinasi RUMUS UMUM DAYA DUKUNG PONDASIMEYERHOF (1963)

  25. F. BENTUK F. KEDALAMAN F. INKLINASI FAKTOR PENGARUH MEYERHOF Q R b T

  26. DISTRIBUSI TEGANGAN TANAH AKIBAT TEG. VERTIKAL DAN MOMEN P M

  27. Tegangan kontak akibat beban vertikal dan momen P M B R e qmin e = B/6 qmax qmin e > B/6 qmin e < B/6 qmax qmax

  28. P e qmin e = B/6 qmax qmin e > B/6 qmin e < B/6 qmax qmax

  29. Pondasi Lajur B B-2e e

  30. StabilitasDayaDukung Tegangankontak : teganganakibatbeban Menentukaneksentrisitas DPT C

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