scantling calc 2007

7/31/2019 Scantling Calc 2007

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Scantling Calculation

Particulars

Frame spacing a=0.5m

Web frame spacing

Length of ship

Breadth of ship

Draft

Height

Block coefficient

Material factor for normal strength hull structure

Bottom shell plating

Length coefficient for length L>90m

Service coefficient for unlimited service range

Distribution factor C F = 1.0 for midship

Wave coefficient C 0

n f = 1.0 for Transverse framing

= 0.83 for Longitudinal framing

Permissible design stress σ perm = 230/K for L>90m

= 230/1.0

= 230

Probability factor = 1.0 for shell plating

Basic external dynamic load p 0 = 2.1 X(C B+ 0.7)X C 0 X C l X f

= 2.1 X(0.6 + 0.7)X 7.92 X 1X 1

= 21.62

Maximum bottom design hull girder bending stress σ LB = 120/k



= 120/1

= 120

Maximum design shear stress due to longitudinal hull girder bending

σ pl

Vertical distance of the structure load centre from base line z = 3.6485 m

Load on sides

External load on ship’s bottom

Corrosion addition t K for thickness <10mm

The thickness of bottom plating should not be less than the greater of the two followingvalues

Or,



So we take the thickness of our bottom plate as

Flat keel plating

The thickness of flat plate keel should not be less than

So we take the thickness of our flat plate keel as

Bilge plating

We take the thickness of our bilge plate as

Side shell plating

The thickness of the side shell plating should not be less than the greater of the twofollowing values

Or,

(In this case p = p S)

So we take the thickness of our side shell plating as

Dimension of centre girder

The depth of the centre girder should not be less than



So we take the depth of centre girder as

The web thickness of the centre girder should not be less than

So we take the thickness of centre girder as

Hence the dimension of the centre girder is

Dimension of side girder

The web thickness of the side girder should not be less than

So we take the thickness of side girder as

Hence the dimension of the side girder is

Thickness of floor plating

The thickness of plate floors is not to be less than

So we take the thickness of floor plating as

Thickness of inner bottom plating

The thickness of inner bottom plating should not be less than



(In this case )

So we take the thickness of inner bottom as

Dimension of main frame

Length of unsupported span

Maximum height of curve s = 0 for main frame

for L>90m

Factor for curved frames

Here,

The section modulus of main frame should not be less than

(In this case )

So we take the section modulus of main frame as

Hence the dimension of the main frame L-section is



Dimension of web frame

Web frame spacing

The section modulus of web frames should not be less than

So we take the section modulus of web frame as

Hence the dimension of the web frame T -section is

Dimension of side stringer

We take the dimension of side stringer same as that of the web frame

Hence dimension of the side stringers are

Dimension of deck beam

Vertical distance of the load centre of the structure above base line

The load on weather deck,

Length of unsupported span

for beams and girders

The section modulus of deck beam should not be less than

(In this case )

So we take the section modulus of deck beam as

Hence the dimension of the deck beam L-section is



Dimension of deck girder

The section modulus of deck girder should not be less than

(In this case )

So we take the section modulus of deck girder as

Hence the dimension of the deck girder T-section is

Dimension of deck web

The section modulus of deck girder should not be less than

(In this case )

So we take the section modulus of deck girder as

Hence the dimension of the deck girder T-section is

Thickness of deck plate

The speed of ship

for midship

So,

Hence acceleration addition



Mean deck height

Static load on cargo

So, The load on cargo deck

The plate thickness of deck plate should not be less than

So we take the thickness of deck plate as

Dimension of brackets

Here for bottom frames

Unsupported span

The section modulus of bottom and inner bottom frames should not be less than

For flanged bracket

The thickness of the bracket should not be less than



So we take the thickness of the brackets as

Now

The arm length of brackets should not be less than

So we take the arm length of bracket as

Dimension of longitudinals

We have

Unsupported span

Hence

0.783

Again

.245

Now



Here

And assuming

The section modulus of bottom longitudinal should not be less than

So we take the section modulus of bottom longitudinal as

Hence the dimension of the bottom longitudinal is

In case of side shell

Unsupported span

The section modulus of side longitudinal should not be less than

So we take the section modulus of side longitudinal as

Hence the dimension of the side longitudinal is

Thickness of bulkhead plating:

Here for bulkheads

We, assume

So,

Spacing of stiffeners

Here, 4.4485m

So,



The thickness of bulkhead plating should not be less than

So we take the thickness of transverse bulkhead as

We also take the thickness of longitudinal bulkhead as

Dimension of stiffeners:

Here

The section modulus of stiffeners should not be less than

So we take the dimension of the stiffener as

Dimension of stem

The cross-sectional area of bar stem should not be less than

So we take the cross-sectional area of bar stem as

Hence the dimension of bar stem as we take is

Keel plate width

The width of flat keel plate should not be less than



So we take the width of flat keel plate as

Hence the half width of flat keel plate as we take is

Shear strake width

The width of shear strake should not be less than

So we take the width of shear strake as

The thickness of shear strake should not be less than the greater of the following twovalues

Or,

So we take the thickness of the shear strake as

scantling calc 2007

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