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Cek Kelangsingan Batang

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Hasil Output SAP 2000

Pu Vu Mu
Profil
Max Min Max Min Max Min
Gelagar Melintang
0 0 49.626 -49.626 94.276 -39.6179
(GM)

Data profil baja gelagar melintang (GM) 400.400.13.21


Kuat Leleh Baja (fy) = 410 Mpa W = 171.68 kg/m
Kuat Tarik Baja (Fu) = 550 Mpa lx = 66600 cm4
Elastisitas Baja (€) = 200000 Mpa ly = 22400 cm4
Angka Poisson (€) = 0.3 rx = 174.5 mm
h = 400 mm ry = 101.2 mm
bf = 400 mm L = 9000 mm
tw = 13 mm Sx = 3330000 mm3
tf = 21 mm Sy = 120000 mm3
Luas Penampang (A) = 21870 mm2 L Jembatan = 31000 mm
Modulus Geser (G) = 80000 Mpa S = mm

1. Cek Kelangsingan Batang


a. Sumbu X (λx)

𝐾 ×𝐿 0.65 × 9000
≤ 200 = ≤ 200
𝑟𝑥 174.5
= 33.5243553 ≤ 200

b. Sumbu Y (λy)
𝐾 ×𝐿 0.65 × 9000
≤ 200 = ≤ 200
𝑟𝑦 101.2
= 57.80632411 ≤ 200
Karena λy > λx, maka perhitungan dilakukan di sumbu Y
2. Cek Kekompakan Batang
a. Flens
𝑏𝑓 250
λf = < λr =
2𝑡𝑓 √𝑓𝑦
400 250
= <
2 × 21 √410
= 9.523809524
< 12.34661996 → 𝐾𝑜𝑚𝑝𝑎𝑘
b. Web
ℎ 665
λw = < λr =
𝑡𝑤 √𝑓𝑦
400 665
= <
13 √410
= 30.76923077
< 32.84200909 → 𝐾𝑜𝑚𝑝𝑎𝑘

3. Kontrol Lentur
a. Menentukan batasan momen plastic (Mp)
1
𝐾𝑜𝑛𝑠𝑡𝑎𝑛𝑡𝑎 𝑃𝑢𝑛𝑡𝑖𝑟 (𝐽) = × 𝑏 × 𝑡3
3
1
= × 400 × 213
3
= 1234800 𝑚𝑚4

1
𝐼𝑤 = × 𝑓𝑦 × ℎ2
4
1
= × 410 × 4002
4
= 16400000 𝑚𝑚6
𝜋 𝐸×𝐺×𝐽×𝐴
𝑋1 = ×√
𝑆𝑥 2

𝜋 200000 × 80000 × 16400000 × 31870


= ×√
3330000 2

= 13872.2882 𝑀𝑃𝑎
𝑆𝑥 2 𝐼𝑤
𝑋2 = 4 × ( ) ×
𝐺×𝐽 𝐼𝑦
2
3330000 16400000
=4×( ) ×
(80000⁄1000) × 1234800 224000000
2
= 0.000332791 𝑚𝑚 ⁄𝑁

𝑍𝑥 = 𝑏 × 𝑡𝑓(𝑑 − 𝑡𝑓) + 1⁄4 𝑡𝑤 × (𝑑 − 2𝑡𝑓)2

= 400 × 21(400 − 21) + 1⁄4 13 × (400 − 2 × 21)2


= 3600133 𝑚𝑚3
𝑀𝑛 = 𝑀𝑝 = 𝑓𝑦 × 𝑍𝑥
= 410 × 4600133
= 1476054530 𝑁𝑚𝑚

b. Menentukan kuat nominal penampang dengan pengaruh tekuk lateral.


Kontrol penampang termasuk bentang pendek, menengah, atau panjang.
𝐿 = 9000 𝑚𝑚

𝐸
𝐿𝑝 = 1.76𝑟𝑦 × √
𝑓𝑦

200000
= 1.76(101.2) × √
410

= 3933.835994 𝑚𝑚
𝑓𝑙 = 𝑓𝑦 − 𝑓𝑟
= 410 − 70
= 340 𝑀𝑃𝑎
𝑋1
𝐿𝑟 = 𝑟𝑦 ( ) × √1 + √1 + 𝑋2 × 𝑓𝑙 2
𝑓𝑙
13872.2882
= 101.2 ( ) × √1 + √1 + 0.000332791 × 3402
340
= 11142.73539 𝑚𝑚
Jadi, Karena Lp < L < Lr, maka penampang termasuk batang menengah.

c. Menentukan kuat lentur plastis Mp


12.5𝑀𝑚𝑎𝑥
𝐶𝑏 = < 2.3
2.5𝑀𝑚𝑎𝑥 + 3𝑀𝑎 + 4𝑀𝑏 + 3𝑀𝑐
12.5(94.276)
= < 2.3
2.5(94.276) + 3(94.276) + 4(39.6179) + 3(94.276)
= 1.227785363 < 2.3
Nilai Cb yang digunakan adalah nilai yang terkecil, yaitu 1.227785363.
𝑀𝑟 = 𝑆𝑥 × (𝑓𝑦 − 𝑓𝑟)
= 3330000 − (410 − 70)
= 1132200000 𝑁𝑚𝑚
𝐿 − 𝐿𝑝
𝑀𝑛 = 𝐶𝑏 (𝑀𝑝 − (𝑀𝑝 − 𝑀𝑟) × ) ≤ 𝑀𝑝
𝐿𝑟 − 𝐿𝑝

= 1.227785363 (1476054530 − (1476054530 − 1132200000)

9000 − 3933.835994
× ) ≤ 1476054530
11142.73539 − 3933.835994
= 1515585022 ≤ 1476054530
∅𝑀𝑛 = 0.9 × 1515585022
= 1364026520
Kontrol kekuatan penampang berdasarkan Mn
𝑀𝑢 ≤ ∅𝑀𝑛
1364026520
94.276 ≤
1000000
94.276 ≤ 1364.02652 → 𝐴𝑀𝐴𝑁‼!
4. Kontrol Kuat Geser

ℎ 𝐸
𝐾𝑒𝑡𝑒𝑏𝑎𝑙𝑎𝑛 min 𝑤𝑒𝑏 = ≤ 2.24√
𝑡𝑤 𝑓𝑦

400 200000
= ≤ 2.24√
13 410

= 30.76923077 ≤ 49.47332368 → 𝐴𝑀𝐴𝑁‼!


Maka, kuat geser nominal = 0.6 × 𝑓𝑦 × 𝐴𝑤
𝐴𝑤 = 𝑡𝑤 × ℎ
= 13 × 400
= 5200 𝑚𝑚2
𝑉𝑛 = 0.6 × 𝑓𝑦 × 𝐴𝑤
= 0.6 × 410 × 5200
= 1279200 𝑁
∅𝑉𝑛 = 0.9 × 𝑉𝑛
= 0.9 × 1279200
= 1151280 𝑁

𝑉𝑢 ≤ ∅𝑉𝑛
1151280
49.626 ≤
1000
49.626 ≤ 1151.28 → 𝐴𝑀𝐴𝑁‼!

5. Parameter Kelangsingan
Ditinjau berdasarkan sumbu terlemah (Y)

𝐿×𝐾 𝑓𝑦
λcy = ×√
𝜋𝑟𝑦 𝐸

9000 × 0.65 410


= ×√
𝜋(101.2) 200000

= 0.832774931
Nilai koefisien tekuk (ω) diambil berdasarkan:
Untuk λcy ≤ 0.25 =1
1.43
Untuk 0.25 ≤ λcy ≤ 1.2 = 1.6−0.67λcy

Untuk λcy ≥ 1.2 = 1.25 λcy2

1.43
Karena Untuk 0.25 ≤ λcy ≤ 1.2, maka nilai ω = 1.6−0.67λcy = 1.372307116

6. Tahanan Nominal Tekan


𝑁𝑛 = 𝐴𝑔 × 𝑓𝑐𝑟
𝑓𝑦
= 𝐴𝑔 × ( )
ω
410
= 21870 × ( )
1.372307116
= 6534033.011 𝑁
∅𝑁𝑛 = 0.85 × 𝑁𝑛
= 0.85 × 6534033.011
= 5553928.059 𝑁

𝑁𝑢 = 𝑃𝑢 ≤ ∅𝑁𝑛
5553928.059
0 ≤
1000
0 ≤ 5553.928059 → 𝐴𝑀𝐴𝑁‼!

7. Tahanan Nominal Tarik


a. Batas leleh (Tn)
𝑇𝑛 = ∅𝐴𝑔 × 𝑓𝑦
= 0.85 × 21870 × 410
= 7621695 𝑁
𝑃𝑢 ≤ 𝑇𝑛
7621695
0 ≤
1000

0 ≤ 7621.695 𝐾𝑁 → 𝐴𝑀𝐴𝑁‼!
b. Batas putus
Nilai b/h = 400/400 >2/3
= 1 > 2/3
Makan nilai reduksi, U = 0.9

Batas putus, 𝑇𝑛 = ∅𝐴𝑛 × 𝑈 × 𝑓𝑢


= (0.9 × 21870) × 0.9 × 550
= 9743085 𝑁
𝑃𝑢 ≤ 𝑇𝑛
9743085
0 ≤
1000

0 ≤ 9743.085 𝐾𝑁 → 𝐴𝑀𝐴𝑁‼!

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