Beam formwork (2) (1)
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Transcript of Beam formwork (2) (1)
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A. Data:
1/ Loads from beam: Beam dimension bxh = 2800 x 850
Load Load factor
Unit weight of concrete 25 KN/m 1.2
Loads from workers and equipments: 2.5 KN/m 1.3
Load from vibrators 2.0 KN/m 1.2
Load from concrete placing by pumping method 4.0 KN/m 1.2
Total Q2:
2/Cross-sectional properties of box steel 50x50 and 50x100
Number
of bars b(mm) h(mm) d(mm) F(mm2) G (kg/m)
1 50 50 2 196 0.1078
2 50 100 2 296 0.1628
B.Calculation:
1. Checking for stress and deflection of FUVI formwork
Distance between two 50x50 bars:
Applied load: 36 KN/m
From the stress-deflection diagram, we obtain the value of deflection:
Deflection limit: [F/l]
=> fmax < [ f ]
Deflection of FUVI formwork satisfies the deflection limit.
To FUVI formwork, it is not necessary to check for stress if deflection limit is satisfied.
CALCULATION OF BEAM'S FORMWORK 2800X850
Name of loads
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2. Checking for stress and deflection of 50x50 box steel bar
Structural idealization: q
Distributed load: q 9 KN/m
Yield strength of box steel 50x50 2100000 KN/m2
Section modulus of box steel 50x50 (m3) 5.90848E-06
Maximum moment in a box steel bar 50x50
Mmax = q*l2/10 = s*W
maximum stress in a box steel bar: 74534.82114 KN/m2
Deflection fmax = q*l4
0.000479764 m
145*E*Jx
Relative deflection 0.000685378
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4. Checking for shoring bars:
Applied load 37.7475 kN T < Pgh
Conclusion:Span lengths of 50*100 and 80*161 bars are the same, 50*100 box steel bar satisfies deflection limit so 80*161 also satisfies that limit.
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mm
Factored load
25.5 KN/m
3.3 KN/m
2.4 KN/m
4.8 KN/m
36.0 KN/m
Jx (cm4) Wx (cm3)
14.7712 5.9085
155.0357 31.0071
250 mm
0.6 mm
0.625 mm
CALCULATION OF BEAM'S FORMWORK 2800X850
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L= 700 mm
Satisfy the strength criterion
Satisfy the deflection limit
The applied loads are concentrated, however, to simplify the calculation, we could consider them as distributed (the difference in results is negligible)
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50.0 kN
Conclusion:Span lengths of 50*100 and 80*161 bars are the same, 50*100 box steel bar satisfies deflection limit so 80*161 also satisfies that limit.
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S tnh l dm 2 nhp vi kch thc mi nhp l 400/2 = 200mm
Ti phn b: q
ng sut gii hn ca vn p
Momen khng un ca di vn p 1m (m3)
Thin v an ton xem momen ln nht trong di coppha vn p di 1m
Mmax = q*l2/10 =
ng sut trong di vn p
vng
vng tng i
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S tnh l dm 2 nhp vi kch thc mi nhp l 400/2 = 200mm
36 KN/m
18000 KN/m3
0.000054
Thin v an ton xem momen ln nht trong di coppha vn p di 1m
s*W
2662.963 KN/m3
Tha mn iu kin chu lc
0.0001205 m
0.0006024 Tha mn iu kin vng