Tower Crane Stability Checks

F4

F3

Tower Crane Base

60 m16.8 mLifting LoadF1 = 0

5.6 m

45.5 m

F2

Counter weight 171 KNPlease refer method statementOf Potain Tower Crane

F3 = Load due to windfor Tower CraneHeight = 45.5 m

PROJECT

DESIGN CALCULATION

CP-5

TOWER CRANE STABILITY CHECK

DESIGN BY CHECKED BY

SHAIKH

Tower Crane Mast1.6 m x3xmTotal 14 Nos ofMast use

As per manufacturers load data sheet for Tower Crane in service and out of service condition they considered 150KM/h wind speed and To Void the toppling counter weight of 72 ton at thebaseand 17.1 ton at the top is provided.(Please refer the attached load data sheet)we checked the stabilty of tower crane considering wind load and counter weight of 17.1 ton.

Load DetailsMaximum Counter weight (Concrete block) F4 = 171 KN (Please refer method statement)Maximum wind Speed considered = 150 Km/hMaximum Dynamic wind Pressure = 3.33 KN/m2 Refer the attached wind calculationTotal Height of Tower Crane = 45.5 mTower crane Windward face of area = 1.6 x45.5 mTotal Height of Counter weight Concrete block = 3 mConcrete block Windward face area = 0.65 x3 mOne Mast Windward face area = 1.6mx3.1m = 4.96 m2No of Mast install =15 NosTotal Height of Mast = 15x3.1 =46.5 m (Actual Height is 45.5) Say = 45.5Total area of Opening in one mast = 2mx 1.64 m2 = 3.28 m2Effective area for wind= 4.96 3.28 = 1.68 m2Counter weight Concrete block Height = 3 mEffective Height of tower crane for wind =45.5-3 = 42.5 mNo of Mast required for 42.5m tower crane height = 42.5/3.1 = 13.7 Say = 14Maximum Dynamic wind Pressure = 3.33 KN/m2 Refer the attached wind calculationTotal effective area of wind for tower crane height = 14x1.68 = 23.52 m2Load due to wind for tower Crane height (F3) = 3.33x23.52 = 78.33 KNMaximum Wind Load due to concrete block Height (F2) = 3.33X3X0.65 =6.5 KN

Check for OverturningTotal Restoring Moment= F4 X 16.8 = 171X16.8 =2872.8 KNmTotal Overturning MomentF3X 22.75 + F2x39.9

78.33X22.75 + 6.5X39.9 = 2042 KNmSafety factored for overturning = Total Restoring Moment /overturning Moment

= 2872.8/2042 = 1.4

1) = 45.5 m

4) = 0.18

Since Cr < 0.25 & H < 300 m , BS 6399 Apply.

5) = 41.67 m/sec

6) Calculation of Site Wind Speed (Vs) = Vb * Sa * Sd * Ss * Sp

As Per BS 6399-2 1997 From Figure 3 Cr can be interpolated

Sa = 1+ 0.001 s

Use s conservatively = 10 m

WIND LOAD CALCULATION

CP-5 Design By

Shaikh

Checked By

Dynamic Augmentation factor Cr

Basic wind speed Vb

3)

2)

PROJECT :

DESIGNCALCULATION

Effective Building height above ground level Hr

( As Per BS 6399 - 2 1997From table -1)4=Building type factor Kb

As Per BS 6399-2 1997 From Figure 3 Cr can be interpolated

WELDED STEEL UNCLAD FRAMESType of Building

Use s conservatively = 10 m

= 1.010 (Section 2.2.2.2)

Sd = 1.000 (Section 2.2.2.3)

Ss = 1.000 (Section 2.2.2.4)

Sp = 1.000 (Section 2.2.2.5)

Vs = 42.0867

Ve = Vs * Sb

As Per BS 6399-2 1997 Table -4 Factor for Sb shall be for the worst case

Sb = 2.1

Ve = 88.38

7) Calculation of Dynamic Pressure (qs) = 0.613 * Ve 2

= 4788.382

= 4.788

Calculation External Pressure co-efficient CPe

WIND X

H = 45.5 m H>B

D = 1.6 m

B = 1.6 m

N/m2

KN/m2

B

D

m/sec

m/sec

Ratio = D / H

= 0.04

WIND Z

B

H = 45.5 m H>B

D = 1.6 m

B = 1.6 m

Ratio = D / H

= 0.04

As Per BS 6399-2 1997 From Table 5 Cpe can be interpolated

WIND WARD (FRONT FACE) = 0.8 (Worst case)

LEE WARD (REAR FACE) = -0.3 (Worst case)

Calculation External Pressure co-efficient Ca From Figure - 4Area Zone = A

a (Diagonal Length) = 45.52812

D

Area Zone = Aa (Diagonal Length) = 45.52812

Ca = 0.87

External Pressures "Pe" = qs * Cpe * Ca

Wind ward Wall = 3.33

1.6

45.5

KN/m2

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waquarul.shaikhTypewritten textCounter Weight

waquarul.shaikhTypewritten textTower Crane Height

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waquarul.shaikhTypewritten textCrane Height

waquarul.shaikhTypewritten textCounter weight