MODUL 8 - BANGUNAN PORTAL DENGAN RASUK GERBER

  STATIKA I MODUL 8 BANGUNAN PORTAL DENGAN RASUK GERBER Dosen Pengasuh :

  Ir. Thamrin Nasution Materi Pembelajaran : 1.

  Portal Kaki Tunggal dengan Rasuk Gerber Memikul Beban Terpusat.

  2. Portal Kaki Tunggal dengan Rasuk Gerber, Garis Pengaruh.

  3. Portal Kaki Tidak Simetris Dengan Dua Rasuk Gerber, Memikul Beban Terbagi Rata.

  4. Portal Kaki Tidak Simetris Dengan Dua Rasuk Gerber, Garis Pengaruh.

WORKSHOP/PELATIHAN

  Tujuan Pembelajaran :  Mahasiswa memahami dan mengetahui tentang gaya-gaya dalam dari struktur portal kaki tunggal dan kaki tidak simetris dengan rasuk gerber, memikul beban terpusat dan terbagi rata, mengetahui cara menggambarkan garis pengaruh.

  DAFTAR PUSTAKA Soemono, Ir., “STATIKA 1”, Edisi kedua, Cetakan ke-4, Penerbit ITB, Bandung, 1985.

  a)

  

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  Wassalam Penulis

  Thamrin Nasution thamrinnst.wordpress.com thamrin_nst@hotmail.co.id

  

BANGUNAN PORTAL DENGAN

RASUK GERBER

1. PORTAL KAKI TUNGGAL DENGAN RASUK GERBER .

MEMIKUL BEBAN TERPUSAT

  P P

  1

  2

  a b c d e (A)

  (F) (D) (C) (G)

  (S) f L

  2

  (E) P

  3

  h g (B)

  L

1 P

  2

  d e (S)

  (F) (G)

  R R

SV FV

  L

  2 P

  1 R SV

  a b c R

  AH

  (D) (C) (S) (A) f

  R

  AV

  (E) P

  3

  h

  IDEALISASI STRUKTUR g (B)

  R

  BV

  L

  1 Gambar 1 : Portal kaki tunggal dengan rasuk gerber, memikul beban terpusat.

  Penyelesaian : Span (S) – (F) .

a. Reaksi Perletakan.

  = 0,  M F R SV . L 2 - P 2 . e = 0 R SV = P

  2 . e/L 2 (ton).

   M S = 0,

  • R . L + P . d = 0

  FV

  2

  2 R = P . d/L (ton). FV

  2

  2 Kontrol :  V = 0, R + R – P = 0

SV FV

  2 b. Gaya lintang.

  D S-G = + R SF D G-F = + R SV – P 2 (ton).

  D = – R (ton).

  G-F FV c. M o m e n .

  M S = 0 M G = + P 2 . d . e/L

  2 M = 0 F

d. Gaya Normal.

  N S-F = 0 (ton).

  .

  Span (A) – (B) – (S) a. Reaksi Perletakan.

   H = 0, R AH - P 3 = 0

  R = P (ton) (ke kanan) AH

  3  M B = 0, R AV . L

  1 + R AH . h – P 1 . b + R SV . c - P 3 . g = 0 R AV = + P 1 . b/L 1 + P 3 . g/L 1 – R AH . h/L 1 – R SV . c/L 1 (ton).

   M A = 0,

  • R BV . L 1 + P

  1 . a + R SV . (c + L

1 ) + P

3 . f = 0 R BV = + P 1 . a/L 1 + P 3 . f/L 1 + R SV . (c + L 1 )/L 1 (ton).

  Kontrol :  V = 0 R AV + R BV = P 1 + R SV b. Gaya Lintang.

  D = + R (ton).

A-D AH

  D D-C = + R AV – P 1 (ton). D C-S = + R AV – P 1 + R BV = + R SV (ton). D C-E = + R AH (ton). D = + R – P = 0 (ton).

E-B AH

  3 c. M o m e n .

  M A = 0 M = + R . a (t.m’).

  D AV M = R . a - P . b (t.m’).

CD AV

1 M CS = - R SV . c (t.m’).

  M CE = - P 3 . f (t.m’)

  (G) (a) Gaya Lintang (b) M o m e n

  (E) (F)

  2

  L

  (C) (D) (S) c d e f g

  1

  L

  (A) (B) h

  (G) b a

  (E) (F)

  2

  L

  (C) (D) (S) c d e f g

  1

  (B) h L

  (G) b a (A)

  (E) (F)

  2

  L

  (S) c d e f g

  (C) (D)

  1

  (B) h L

  b a (A)

  

Gambar 2 : Bidang-bidang gaya lintang, momen dan gaya normal.

  N C-B = – R BV ton (tekan).

  AH ton (tekan).

  A-C = – R

  M B = 0 d. Gaya Normal. N

  (c) Gaya Normal

2. PORTAL KAKI TUNGGAL DENGAN RASUK GERBER GARIS PENGARUH (Influence Line).

  (G) (D)

  (A) (F)

  (C) (S) d e

  L

  2

  h (B) a b c

  L

  1

  • e/L

  2

  • 1

  G.p. R

  S d/L

  2

  • 1

  G.p. R

  F e/L

  2

  • 1

  G.p. D

  G

  • 1
    • – - d/L

  2 d.e/L

  2

  • G.p. M

  G

Gambar 3 : Garis pengaruh span (S)-(F), section (G).

  Diminta : Gambarkanlah garis pengaruh gaya lintang, momen dan gaya normal untuk potongan (D), (G) dan (F). Penyelesaian : .

  Span (S) - (F) a. Garis pengaruh R S .

  P = 1 t berada di (S), R S = + P = + 1 (ton) P = 1 t berada di (G), = 0

   M F R S = + P . e/L 2 = + 1 . e/L 2 (ton)

  P = 1 t berada di (F), R S = 0 (ton) b. Garis pengaruh R F P = 1 t berada di (S),

  R F = 0 (ton) P = 1 t berada di (G),  M S = 0 R = + P . d/L = + 1 . d/L (ton)

  F

  2

2 P = 1 t berada di (F),

  R S = + P = + 1 (ton) c. Garis pengaruh Gaya lintang pada titik (G). P = 1 t berada di (S), R S = + P = + 1 t,

  D G = R S – P = 0 P = 1 t berada di (G), P belum melewati (G), = 0  M F

  R = + P . e/L (ton) S

  2 D G = R S – P = P.e/L 2 – P = P . (L 2 - d)/L 2 – P . L 2 /L 2 = – P . d/L

  2 D G = – d/L 2 (ton) P = 1 t berada di (G), P sudah melewati (G), = 0

   M F R S = + P . e/L 2 (ton)

  Dc = + R S = + P . e/L 2 (ton) P = 1 t berada di (F), = 0  M B

  R = 0 (ton) S

  D G = R S = 0 (ton) d. Garis pengaruh Momen pada titik (G). P = 1 t berada di (S), R = + P = + 1 (ton)

  S M G = (R S – P) . d = 0 (t.m’) P = 1 t berada di (G),  M F = 0 R = + P . e/L = + 1 . e/L (t.m’)

  S

  2

  2 M G = R S . d = d . e/L 2 (t.m’) P = 1 t berada di (F), R S = 0 (ton)

  M = 0 (t.m’) G

  Span (A) - (B) a. Garis pengaruh R A .

  P = 1 t berada di (A), R = + P = + 1 (ton) A

  P = 1 t berada di (C),  M B = 0 R A = 0 (ton) P = 1 t berada di (S),  M B = 0, R A . L

  1 + P . c = 0 R A = - P . c/L 1 = - 1 . c/L 1 (ton) P = 1 t berada di (F), R = 0 (ton).

  A e d b a

  • 1
  • 1
    • – b/L
      • c/L

  1

  (c + L

  1 )/L

  1

  1 a/L

  1

  2 . (c + L

  1 )/L

  • 1
    • – a.b/L
    • – e/L
      • c/L

  1

  1

  1

  1

  B-C

  1

  1

  2 . (c + L

  1 )/L

  1

  1 b/L

  D

  1 G.p. M D

  G.p. D

  

Gambar 4 : Garis pengaruh span (A)-(B), section (D), gaya normal kolom (B)-(C).

  P = 1 t berada di (A), R B = 0 (ton) P = 1 t berada di (C),  M B = 0

  R B = + P = +1 (ton).

  (A) (B) h

  L

  1

  (C) (D)

  (S) c f g

  (E) (F)

  (G) L

  2

  G.p. R

  A

  G.p. R

  B

  • 1
  • a/L
      • – G.p. N

  • a . c/L

    • e/L

  • a/L
  • 1
  • (c + L 1 )/L

b. Garis pengaruh R B .

  P = 1 t berada di (S),  M A = 0,

  • R . L + P . (c + L ) = 0

  B

  1

  1 R B = + P . (c + L 1 )/L 1 = + 1 . (c + L 1 )/L 1 (ton) P = 1 t berada di (F), R B = 0 (ton).

c. Garis pengaruh Gaya lintang pada titik (D).

  P = 1 t berada di (A), R A = + P = + 1 t, D D = R A – P = 0 P = 1 t berada di (D), P belum melewati (D),  M = 0

  B R A = + P . b/L 1 (ton) D D = R A – P = P.b/L

  1 – P = P . (L 1 - a)/L 1 – P . L 1 /L 1 = – P . a/L

  1 D D = – a/L 1 (ton) P = 1 t berada di (D), P sudah melewati (D),  M B = 0

  R A = + P . b/L 1 (ton) D D = + R A = + P . b/L 1 (ton)

  P = 1 t berada di (C),  M = 0 B

  R A = 0 (ton) D D = R A = 0 (ton) P = 1 t berada di (S), = 0,

   M A

  • R A . L 1 + P . c = 0 R A = - P . c/L

  1 = - 1 . c/L 1 (ton) D D = R A = - c/L

1 P = 1 t berada di (F), R = 0 (ton).

  A D D = 0 (ton).

d. Garis pengaruh Momen pada titik (D).

  e. Garis pengaruh gaya normal P = 1 t berada di (A), kolom (B)-(C). R = + P = + 1 (ton)

  

A P = 1 t berada di (A),

M D = (R A – P) . a = 0 (t.m’) R B = 0 (ton)

  P = 1 t berada di (D), N B-C = - R B = 0 (ton) P = 1 t berada di (C),  M B = 0

  R = + P . b/L = + 1 . b/L (t.m’) A

  1 1 = 0  M B M = R . a = a . b/L (t.m’)

  D A

1 R B = + P = +1 (ton)

  P = 1 t berada di (C), N B-C = - R B = - 1 (ton).

  R A = 0 (ton) P = 1 t berada di (S), M D = 0 (t.m’)

  = 0,  M A P = 1 t berada di (S),

  • R B . L 1 + P . (c + L

  1 ) = 0  M A = 0, R B = + P . (c + L

  1 )/L

  1

  • R A . L 1 + P . c = 0 = + 1 . (c + L

  1 )/L 1 (ton) R A = - P . c/L 1 = - 1 . c/L 1 (ton) N = - R

  B-C B M = R . a = - a .c/L (t.m’)

  D A 1 = - 1 . (c + L )/L (ton)

  1

  1 P = 1 t berada di (F), P = 1 t berada di (F), R A = 0 (ton).

  R B = 0 (ton). M D = 0 (t.m’).

  N B-C = - R B = 0 (ton)

3. PORTAL KAKI TIDAK SIMETRIS DENGAN DUA RASUK GERBER MEMIKUL BEBAN TERBAGI RATA .

  a b c q t/m’ q t/m’

  2 q t/m’

  1

  3

  (A) (E) (F)

  (S ) (S )

  2

  1

  (D) H

  2 H

  1

  (C) 

  (B) L L L

  1

  

2

  3

  q t/m’ q t/m’

  1

  3

  (S ) (A)

  (D)

  2

  (S )

1 R

  R

  

AV R S2V R

S1V DV

  L L

  1

  3 R S1V q t/m’

  2 R S2V

  (S ) (S )

  1

  2

  (E) (F)

  

X

IDEALISASI STRUKTUR

  H

  2 H

  1

  (C) 

  R

  CV

  (B) R

  BV

  a b c L

  

2

Gambar 5 : Portal kaki tidak simetris dengan dua rasuk gerber.

  Penyelesaian : .

  Span (A) – (S 1 ) a. Reaksi Perletakan.

   M S1 = 0,

  2 R AV . L 1 - ½ . q 1 .L 1 = 0 R AV = ½ q 1 .L 1 (ton). R = R = ½ q .L (ton).

S1V AV

  1

  1 Kontrol :  V = 0, R + R = q . L

  AV S1V

  1

  1 b. Gaya Lintang.

  D AS1 = R AV = ½ q 1 .L 1 (ton) D S1A = R AV – q 1 .L 1 = – R S1 = – ½ q 1 .L 1 (ton).

  c. Momen.

  M A = 0 (t.m’).

  2 M maks = 1/8 q 1 .L 1 (t.m’).

  M S1 = 0 (t.m’).

  Span (S ) – (D) .

  2 a. Reaksi Perletakan.

   M D = 0,

  2 R S2V . L 3 - ½ . q 3 .L 3 = 0 R = ½ q .L (ton). S2V

  3

  3 R = R = ½ q .L (ton). DV S2V

  3

  3 Kontrol :  V = 0, R + R = q . L

  S2V DV

  3

  3 b. Gaya Lintang.

  D S2D = R S2V = ½ q 3 .L 3 (ton) D = R – q .L = – R = – ½ q .L (ton).

  DS2 S2V

  3

  3 DV

  3

  

3

c. Momen.

  M S2 = 0 (t.m’).

  2 M maks = 1/8 q 3 .L 3 (t.m’).

  M = 0 (t.m’).

  D Span (B) – (C) .

  a. Reaksi Perletakan.

   M C = 0,

R . L – R . (a + b) – q .(a + b).1/2.(a + b) + q .(c).1/2.(c) + R . (c) = 0

BV

  2 S1V

  2

  2 S2V

  

2

  2 R = + R .(a + b)/L + 1/2 q .(a + b) /L – 1/2 q .(c) /L – R .(c)/L = 0 BV S1V

  2

  2

  2

  2

  2 S2V

  2  M B = 0,

  • – R . L – R . (a – H /tg .(L + c).1/2.(L + c) –

  CV

  2 S1V 1  ) + q

  2

  

2

  2 q .(a + b – L ).1/2. (a + b – L ) + R . (L + c) = 0

  2

  2

  2 S2V

  2

  2

  2 R CV = – R S1V .(a – H 1 /tg  )/L 2 + ½.q 2 .(L 2 + c) /L 2 – ½.q 2 .(a + b – L 2 ) /L

  2

  • R S2V .(L 2 + c)/L

  2 Kontrol :

  R

  BV

  R Sin 

  BV  V = 0, R BV + R CV = R S1V + q

  2 . (a + b + c) + R S2V b. Gaya Lintang.

  D B-E = + R BV Cos 

   R Cos 

  BV D S1E = – R S1V (ton). D ES1 = – R S1V – q 2 . a (ton). D EF = – R S1V – q 2 . a + R BV (ton). D = – R – q . (a + b) + R (ton).

  FE S1V

  2 BV D = – R – q . (a + b) + R + R (ton). FS2 S1V

  2 BV CV D S2F = – R S1V – q 2 . (a + b + c) + R BV + R CV (ton) = – R S2V (ton).

  c. M o m e n .

  M = 0 B M = + R . a (t.m’).

  EB BV

  2 M ES1 = – R S1V . a – ½.q 2 . a (t.m’).

  2 M EF = – R S1V . a – ½.q 2 . a + R BV . a (t.m’).

  Momen yang terjadi pada titik sejauh x dari (F),

  

2

Mx = – R S1V . (a + x) – ½.q 2 . (a + x) + R BV . (H 1 /tan  + x) Momen maksimum terjadi pada titik dimana gaya lintang Dx = 0, yaitu

  

2

  2 Mx = – R .a – R . x – ½.q . (a + 2ax + x ) + R . (H /tan S1V S1V

  2 BV 1  + x) d(Mx)/dx = – R S1V – q 2 . a – q 2 . x + R BV = 0 x = (– R S1V – q

  2 . a + R BV )/q

2 (m), dari titik (E).

  Titik dimana momen Mx = 0, adalah

  2 Mx = – R S1V . (a + x) – ½.q

2 . (a + x) + R BV . (H

1 /tan  + x) = 0

  2 ½.q 2 . (a + x) + R S1V . (a + x) – R BV . (H 1 /tan  + x) = 0

Selanjutnya persamaan diatas diselesaikan dengan rumus abc, sebagai berikut,

  2

  b b ac   

  4 x

  

  1 ,

  2

  a

  2

  2 M FE = – R S1V . a – ½.q 2 .(a + b) + R BV . a (t.m’).

  Atau,

  2 M = – R . c – ½.q . c (t.m’). FS2 S2V

  2 M = M (t.m’). FE FS2 M FC = 0 (t.m’).

  d. Gaya Normal.

  N = – R Sin B-E BV  (ton) (tekan). N C-F = – R CV (ton) (tekan).

  (S )

  • 1 (F)

  (E) (A)

  (F) (S )

  2

  • – – –

  (D) Bidang Gaya Lintang

  • (C)

   (B)

  L L L

  1

  

2

  3

  • (F)

  (E) (A)

  (S )

  • – (S )

  2

  • – 1

  (D)

  • Bidang M o m e n

  (C) 

  (B) L L L

  1

  

2

  3 Bidang

  Gaya Normal (F)

  (E) (A)

  (S )

  

1 (S )

  2

  (D)

  BV R BV Sin 

  • – R
  • – H

  2 H

  1

  (C) 

  R Cos  BV

  (B) L L L

  1

  

2

  3

  a b c

Gambar 6 : Bidang-bidang gaya lintang, momen dan gaya normal..

4. PORTAL KAKI TIDAK SIMETRIS DENGAN DUA RASUK GERBER GARIS PENGARUH .

  

2

  ) (S

  x

  b a c

  (F)

  ) 

  2

  (A) (B)

  (C) (D)

  (E) (F)

  L

  3

  (S

  1

1 L

  • 1
  • <>1 <
  • L
  • 1
  • 1
    • 1 G.P.D G.P.M

  • – –
  • 1

  • 1 G.P.D G.P.M
    • (a + b)/L

  • c/L
    • – +

  • (L 2 + c)/L
  • 1 G.P.R C
  • X

    • – +

  • (a – H

  2 -D dan balok E-F .

  1 , S

  X

  X G.P.M

  2

  2

  (a – H 1 /tan )/L

  2

  1 /tan )/L

  2

  2

  2

  G.P.R B

  G.P.R D G.P.R S2

  G.P.R A G.P.R S1

  • 1

G.P.D

  • c/L

  • 1

  • – –
a b c x (F)

  Gambar 7 : Garis pengaruh reaksi, gaya lintang dan momen balok A-S

  (E) (A)

  (F) (S ) (S )

  2

  1

  (D) R

   BV R BV Sin

  (C) 

  R BV Cos 

  (B) L L L

  1

  

2

  3 c/L

  2 Sin 

  • G.P.N

  B-E

  • – - 1 . Sin 
    • (a + b)/L 2 . Sin   (a + b)/L

  2 . Cos 1 . Cos   c/L

  2 Sin

  • G.P.D

  B-E

  • – Garis pengaruh Gaya Normal dan Gaya lintang kolom B – E )/L (a – H

  1 /tan

  2

  • G.P.N C-F
    • – - 1 Garis pengaruh Gaya Normal kolom C – F - (L

  2 + c)/L

  2 Gambar 8 : Garis pengaruh gaya normal dan gaya lintang kolom B – E dan C – F.

  (B) h L

  AH

  1

  (C) (D) (S) a b c

  P L

  2

  (E) q t/m’ (A)

  (B) h L

  1

  (D) (S) a b c

  P L

  2

  (E) q t/m’ R

  AV

  R

  R

  

WORKSHOP/PELATIHAN

Diketahui : Struktur seperti tergambar.

  BV

  R

  SV

  R

  SV

  R

  CV

  q t/m’

  IDEALISASI STRUKTUR

  X

  a h b c q P Stb. m m m m m m t/m' ton

  2

  No. L

  

Diminta : Gambarkan bidang-bidang gaya lintang, momen dan gaya normal pada

seluruh bentang. Penyelesaian : DATA.

1 L

  • 1

  3.10

  9

  2

  3.50 (A)

  3.50

  3.00

  2.00

  5.00

  2.00

  4.50

  8.00

  3.35

  1.50

  3.25

  2.94

  1.96

  4.90

  1.90

  4.30

  7.60

  8

  3.20

  2.30

  2.52

  2.88

  2.70

  4.00

  2.50

  1.00

  4.00

  1.60

  2.40

  1.00

  2.00

  4.40

  1.10

  1.68

  4.10

  1.64

  2.46

  1.25

  2.15

  1

  4.80

  2.90

  1.20

  4.20

  3.00

  1.92

  1.30

  1.76

  1.80

  4.50

  1.50

  3.50

  6.00

  4

  2.60

  2.00

  2.64

  4.40

  2.25

  1.40

  3.30

  5.60

  3

  2.45

  1.75

  2.58

  1.72

  4.30

  2.70

  2.75

  4.80

  1.70

  1.80

  4.10

  7.20

  7

  3.05

  2.75

  2.82

  1.88

  4.70

  3.90

  5

  6.80

  6

  2.90

  5.20

  2.76

  1.84

  4.60

  1.60

  3.70

  6.40

  2.50 Pada contoh ini, X = -1 SPAN (S) – (C) a). Reaksi perletakan.

  R = ½ q L = ½ . (1 t/m’) . (2,50 m) = 1,25 ton.

  SV

  2 R = R = ½ q L = 1,25 ton. CV SV

  2 Kontrol : R + R = q . L

  SV CV

  2 1,25 ton + 1,25 ton = (1 t/m’).(2,5 m) (memenuhi).

  b). Gaya lintang.

  D = + R = + 1,25 ton.

  SC SV D = + R – q.L = 1,25 ton – (1 t/m’).(2.5 m) = – 1,25 ton. CS SV

  2 c). Momen.

  2

  2 Mmaks = 1/8 q.L = 1/8 . (1 t/m’).(2,5 m) = 0,78125 t.m’.

  2 SPAN (A) – (B) – (S) a). Reaksi perletakan.

   H = 0, R + P = 0 AH R = – P = – 2,000 ton (ke kiri). AH

  = 0,  M B

  2

  2 R . L – R . h – ½ . q . L + ½ . q . a + R . a + P . c = 0 AV

  1 AH

  1 SV

  2

  2 R = R . h/L + ½ . q . (L – a )/L – R . a/L – P . c/L AV AH

  1

  1

  1 SV

  1

  1

  2

  2 = (2,0 t).(4,0 m)/(4,0 m) + ½.(1 t/m’).{(4 m) – (1 m) }/(4 m) – (1,25 t).(1 m)/(4 m)

  • – (2 t).(2,40 m)/(4 m) R = 2,0000 + 1,8750 – 0,3125 – 1,2000 = 2,3625 ton.

  AV = 0,  M

  A

  2

  • – R . L + ½ . q . (L + a) + R . (L + a) – P . b = 0

  BV

  1

  1 SV

  1

  2 R = ½ . q . (L + a) /L + R . (L + a)/L – P . b/L BV

  1

  1 SV

  1

  1

  1

  2 = ½.(1 t/m’).{(4 m) + (1 m)} /(4 m) + (1,25 t).{(4 m) + (1 m)}/(4 m)

  • – (2 t).(1,6 m)/(4 m)

  3,1250 + 1,5625 R = – 0,8000 = 3,8875 ton.

  BV Kontrol : R + R = q . (L + a) + R

  AV BV

  1 SV 0,3625 t + 3,8875 t = (1 t/m’) . (4 m + 1 m) + 1,250 t 6,250 t = 6,250 t (memenuhi) b. Gaya Lintang.

  D = + R = + 2,3625 (ton).

  AD AV D = + R – q . L = 2,3625 – (1 t/m’).(4 m) = – 1,6375 (ton). DA AV

  1 D = + R – q . L + R = 2,3625 – (1 t/m’).(4 m) + 3,8875 = + 2,250 (ton). DS AV

  1 BV Atau, D = + q . a + R = (1 t/m’).(1 m) + 1,25 = + 2,250 (ton)

  DS SV D = – R = – 2 (ton). DE AH D = – R + P = – 2 + 2 = 0 (ton). EB AH c. M o m e n .

  M = 0 A

  2

  2 M = + R . L – ½ . q . L = (2,3625 t).(4 m) – ½.(1 t/m’).(4 m) = + 1,4500 (t.m’). DA AV

  1

  1

  2

  2 M = – ½ . q . a – R . a = – ½.(1 t/m’).(1 m) – (1,25 t).(1 m) = – 1,7500 (t.m’). DS SV M = + P . b = + (2 t) . (1,6 m) = + 3,2000 (t.m’).

  DE

2 Momen maksimum terjadi pada titik dimana gaya lintang Dx = 0, yaitu

  • – q . x = 0 x = R

  Apabila M DA bertanda negatip, maka Mx = + R

  = + R AH = + 2,000 (ton) (tarik).

  N A-D

  AV /q d. Gaya Normal.

  AV

  2 = 0 R

  AV . x – ½.q . x

  2 = 2,79070 (t.m’).

  Apabila pada bentang (A)-(D), momen M DA bertanda positip, maka tidak terdapat titik peralihan momen dari positip ke negatip, titik dimana momen Mx = 0.

  = – R BV = – 3,8875 (ton) (tekan).

  Mmaks = (2,3625 t).(2,3625 m) – ½ . (1 t/m’) . (2,3625 m)

  AV /q = (2,3625 t)/(1 t/m’) = 2,3625 (m), dari titik (A).

  d(Mx)/dx = R AV

  . x – ½.q . x

  Momen yang terjadi pada titik X sejauh x dari (A), Mx = + R AV

  • – ½.q . x = 0 x = 2 R

  N B-D

e. Bidang-bidang gaya lintang, momen dan gaya normal dipersilahkan digambar sendiri.

  Kunci Jawaban SPAN (S) – (C)

  • 1 1.250 1.250 1.250 -1.250 0.78125

  BV q.(L 1 +a)+R SV Stb.

  R

  AV

  R

  BV

  R

  AV

  2.0000 2.3625 3.8875 6.250 6.250 2.1500 2.9576 5.6049 8.563 8.563 1 2.3000 3.6363 7.5388 11.175 11.175

  ton ton ton ton ton

  No. R

  2 2.4500 4.3979 9.6896 14.088 14.088

  3 2.6000 5.2421 12.0579 17.300 17.300

  4 2.7500 6.1688 14.6438 20.813 20.813 5 2.9000 7.1775 17.4475 24.625 24.625

  6 3.0500 8.2682 20.4693 28.738 28.738

  7 3.2000 9.4408 23.7092 33.150 33.150

  8 3.3500 10.6952 27.1673 37.863 37.863 9 3.5000 12.0313 30.8438 42.875 42.875

  AH

  SPAN (A) – (B) – (S) Reaksi Perletakan

  No. R

  SC

  SV

  R

  CV

  D

  SC

  D

  1.688 1.688 1.688 -1.688 1.13906

  9 7.875 7.875 7.875 -7.875 8.85938

  1 2.175 2.175 2.175 -2.175 1.57688

  2 2.713 2.713 2.713 -2.713 2.10219

  3 3.300 3.300 3.300 -3.300 2.72250

  4 3.938 3.938 3.938 -3.938 3.44531

  5 4.625 4.625 4.625 -4.625 4.27813

  6 5.363 5.363 5.363 -5.363 5.22844 7 6.150 6.150 6.150 -6.150 6.30375

  8 6.988 6.988 6.988 -6.988 7.51156

  Mmaks Stb. ton ton ton ton t.m'

  • R
    • 1
    Gaya Lintang

  No. D D D D D D

  AD DA DS kiri DS kanan DE EB Stb.

  ton ton ton ton ton ton

  • 1 2.3625 -1.6375 2.2500 2.2500 -2.000

  0.0 2.9576 -2.5424 3.0625 3.0625 -2.150

  0.0

  1 3.6363 -3.5638 3.9750 3.9750 -2.300

  0.0

  2 4.3979 -4.7021 4.9875 4.9875 -2.450

  0.0

  3 5.2421 -5.9579 6.1000 6.1000 -2.600

  0.0 4 6.1688 -7.3313 7.3125 7.3125 -2.750

  0.0

  5 7.1775 -8.8225 8.6250 8.6250 -2.900

  0.0

  6 8.2682 -10.4318 10.0375 10.0375 -3.050

  0.0

  7 9.4408 -12.1592 11.5500 11.5500 -3.200

  0.0 8 10.6952 -14.0048 13.1625 13.1625 -3.350

  0.0

  9 12.0313 -15.9688 14.8750 14.8750 -3.500

  0.0 M o m e n No. M M M x = R /q Mmaks x = 2R /q

  

DA DS DE AV AV

Stb.

  t.m' t.m' t.m' m t.m' m

  • 1
  • 1.45000 -1.75000 3.20000 2.36250 2.79070 0.91350 -2.61250 3.52600 2.36609 3.49899 -

  1

  • 0.17400 -3.69000 3.86400 2.42417 4.40744 2 -0.79100 -5.00500 4.21400 2.51308 5.52611 5.026

  3

  • 2.00400 -6.58000 4.57600 2.62107 6.87002 5.242

  4

  • 3.48750 -8.43750 4.95000 2.74167 8.45633 5.483

  5

  • 5.26400 -10.60000 5.33600 2.87100 10.30330 5.742 6 -7.35600 -13.09000 5.73400 3.00663 12.42977 6.013

  7

  • 9.78600 -15.93000 6.14400 3.14694 14.85489 6.294

  8

  • 12.57650 -19.14250 6.56600 3.29083 17.59804 6.582

  9

  • 15.75000 -22.75000 7.00000 3.43750 20.67871 6.875

  Gaya Normal

  No. N N

  A-D B-D Stb.

  ton ton

  • 1

  2.0000 -3.8875 2.1500 -5.6049

  1 2.3000 -7.5388

  2 2.4500 -9.6896

  3 2.6000 -12.0579 4 2.7500 -14.6438

  5 2.9000 -17.4475

  6 3.0500 -20.4693

  7 3.2000 -23.7092 8 3.3500 -27.1673

  9 3.5000 -30.8438