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

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

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.

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

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)

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.

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

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