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Design of Concrete Corbel
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UNITS:SI1
Normal-weight
SIEnglish
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SI1E =200000MPa
Agregate, λ =
Normal-weightSand-weight
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Englishfc' =30MPa1,41Lightweight215000
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fy =450MPaFriction, μ =1.4λ for Concrete cast monolithically.48060000
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Dimensions:
1.4λ for Concrete cast monolithically.
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a =250mm
1.0λ for Concrete placed against hardened rough concrete.
755
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d =500mm
0.6λ for Concrete placed against unroughened hardened concrete.
15014
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h =600mm
0.7λ for Concrete anchored to structural steel.
19018
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b =500mm15010
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Remarks: Safe!
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Reinforcement sizes:
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Primary tension: 500mm196349,540889670,875
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Closed stirrups: 10mm157,07963279,3750,375
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Framing: 10mm78,539816349,3750,375
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Welded anchor: 22mm380,132711121,8750,875
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Concrete cover =30mm402,75
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Allowable clear spacing =25mm251
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Remarks: not OK!
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Loads:
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VDL = 50kN50000151,823976
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VLL = 300kN30000023,1285623,12856
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[Optional] VU = 0kN014080
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[Optional] NU = 0kN
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Vu =
1.4VDL + 1.7VLL
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=60kNor60000N
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Nu =0kNor0N
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Vn Vu=60000
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Ø0,75
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Vn =712,000N
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0.2f`cbwd =1500000MPa
> Vu = 60000 N OK!
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5,5158068bwd =1378951,7MPa
> Vu = 60000 N OK!
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Avf =Vu
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Øfyμ
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=712,000
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450(1,4)
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=1,130mm²
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Af =Mn=Vua+Nu(h-d)
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ØfyjdØfyjd
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where: jd ≈ 0.85d
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jd =425mm
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Act Nu=0N
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Min Nu=0.20Vu
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=12000N
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Use: Nu=12000N
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Af =60000(250)+12000(600-500)
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0.90(450)(425)
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=16200000
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172125
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Af =94,118mm²
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An =Nu=12000
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Øfy0,75(450)
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=35,556mm²
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Primary steel:
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(a)As =2/3Avf + An=
2/3(1,13) + 35,556
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=36,309
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(b)As =Af + An=
(94,118) + 35,556
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=129,673mm²
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min As = 0.04f`cbd
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fy
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= 0.0430(500)(500)
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450
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Min As=666,667mm²
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Therefore: since case (a) governs
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As =129,673mm²
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n =0,001say2
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Soc = -60,000mm
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Scl = -560,000mmNot OK!
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Horizontal closed stirrups:
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since case (a) governs
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Ah =1/2Af
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=47,059
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=47,059mm²
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Min .Ah =
0.5(As -An)
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=
0.5(36,309 - 35,556)
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=0,377mm²
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Use: Ah =47,059mm²
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n =0,300say2
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Soc = 333,333mm
spread above 2/3d =
333,333mm
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Scl = 323,333mmOK!
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