vol2_section10
TRANSCRIPT
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Section 10 - Deck Beams and Supporting Deck Structures B 10 - 1
Section 10
Deck Beams and Supporting Deck Structures
A. General
1. Definitions
k = material factor according to Section 2, B.2.
= unsupported span [m] according to Section 3,
C.
e = width of deck supported, measured from centre
to centre of the adjacent unsupported fields [m]
p = deck load pD, pDAor pL [kN/m2], according
to Section 4, B. and C.c = 0,55
= 0,75 for beams, girders and transverses which
are simply supported on one or both ends.
Ps = pillar load
= P A + Pi[kN]
A = load area for one pillar [m2]
Pi = load from pillars located above the pillar
considered [kN]
s
= degree of slenderness of the pillar
= 0,2s
is
ReH
E
s = length of the pillar [cm]
is = radius of gyration of the pillar
=Is
As[cm]
= 0,25 ds for solid pillars of circular cross
section
= 0,25 for tubular pillarsd2
a d2
i
Is = moment of inertia of the pillar [cm4]
As = sectional area of the pillar [cm2]
ds = pillar diameter [cm]
da = outside diameter of pillar [cm]
di = inside diameter of pillar [cm].
ma = factor according to Section 9, A.1.2
2. Permissible stresses
Where the scantlings of girders not forming part of the
longitudinal hull structure, or of transverses, deck beams,
etc. are determined by means of strength calculations the
following stresses are not to be exceeded:
b = [N/mm2]
150
k
= [N/mm2]
100
k
v = [N/mm2]2 32
180
k
3. Buckling strength
In order to achieve adequate buckling strength of the
orthotropic plate panels of the strength deck as per Section.3,
F.2. it may be necessary to strengthen the transverse deck
beams within 0,6Lamidships for the purpose of increasing
the moment of inertia. For this purpose the design stresses
according to Section 5, D.1. and the stresses due to local
loads are to be considered.
B. Deck Beams and Girders
1. Transverse deck beams and deck longitudinals
The section modulus Wdand shear area Adof transverse
deck beams and of deck longitudinals between 0,25 Hand
0,75 Habove base line is to be determined by the following
formula:
Wd = c a p .2. k [cm3].
Ad = (1 - 0,817 ma) 0,05 a p k [cm2],
2. Deck longitudinals in way of the upper and lower
hull flange
The section modulus of deck longitudinals of decks locatedbelow 0,25 Hand/or above 0,75 Hfrom base line is to be
calculated according to Section 9, B.
3. Attachment
3.1 Transverse deck beams are to be connected to the
frames by brackets according to Section 3, D.2.
3.2 Deck beams crossing longitudinal walls and girders
may be attached to the stiffeners of longitudinal walls and
the webs of girders respectively by welding without
brackets.
3.3 Deck beams may be attached to hatchway coamingsand girders by double fillet welds where there is no
constraint. The length of weld is not to be less than 0,6 x
depth of the section.
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Section 10 - Deck Beams and Supporting Deck Structures C10 - 2
3.4 Where deck beams are to be attached to hatchway
coamings and girders of considerable rigidity (e.g. box
girders), brackets are to be provided.
3.5 Within 0,6 Lamidships, the arm lengths of the beam
brackets in single deck ships are to be increased by 20%.
The scantlings of the beam brackets need, however, not
be taken greater than required for the Rule section modulus
of the frames.
3.6 Regarding the connection of deck longitudinals to
transverses and bulkheads, Section 9, B.1. is to be observed.
4. Girders and transverses
4.1 The section modulus W and shear area Aware not
to be less than:
W = c e2 p k [cm3].
Aw = 0,05 p e k [cm2].
4.2 The depth of girders is not to be less than 1/25 of
the unsupported span. The web depth of girders scalloped
for continuous deck beams is to be at least 1,5 times the
depth of the deck beams.
Scantlings of girders of tank decks are to be determined
according to Section 12, B.3.
4.3 Where a girder does not have the same section
modulus throughout all girder fields, the greater scantlings
are to be maintained above the supports and are to be
reduced gradually to the smaller scantlings.
4.4 End attachments of girders at bulkheads are to be
so dimensioned that the bending moments and shear forces
can be transferred. Bulkhead stiffeners under girders are
to be sufficiently dimensioned to support the girders.
4.5 Face plates are to be stiffened by tripping brackets
according to Section 3, H. 2.5. At girders of symmetrical
section, they are to be arranged alternately on both sides
of the web.
4.6 For girders in line of the deckhouse sides under thestrength deck, see Section 16, A.3.2.
4.7 For girders forming part of the longitudinal hull
structure and for hatchway girders see E.
5. Supporting structure of windlasses and chain
stoppers
5.1 For the supporting structure under windlasses and
chain stoppers, the following permissible stresses are to
be observed:
b = [N/mm
2
]
200
k
= [N/mm2]
120
k
v = [N/mm2]2 32
220
k
5.2 The acting forces are to be calculated for 80% and
45% respectively of the rated breaking load of the chain
cable, i.e.:
S for chain stoppers80%
S for windlasses 80%, where chain stoppers
are not fitted.
for windlasses 45%, where chain stoppers
are fitted.
See also Rules for Machinery Installations, Volume III,
Section 14, D. and Rules for Materials, Volume V,
Section 12, Table.12.7.
C. Pillars
1. General
1.1 Structural members at heads and heels of pillars as
well as substructures are to be constructed according to
the forces they are subjected to. The connection is to be
so dimensioned that at least 1 cm2cross sectional area is
available for 10 kN of load.
Where pillars are affected by tension loads doublings are
not permitted.
1.2 Pillars in tanks are to be checked for tension. Tubular
pillars are not permitted in tanks for flammable liquids.
1.3 For structural elements of the pillars' transverse
section, sufficient buckling strength according to Section.3,
F. has to be verified. The wall thickness of tubular pillars
which may be expected to be damaged during loading and
unloading operations is not to be less than:
tw = 4,5 + 0,015 da [mm] for da 300 mm
tw = 0,03 da [mm] for da> 300 mm
da = outside diameter of tubular pillar in [mm]
1.4 Pillars also loaded by bending moments have to be
specially considered.
2. Scantlings
The sectional area of pillars is not to be less than:
As req = [cm2]10
Ps
p
p = permissible compressive stress.
=
SR
eH
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Section 10 - Deck Beams and Supporting Deck Structures E 10 - 3
= reduction factor
=1
2 s2
= 0,5 1 np
(s 0,2)
s2
np = 0,34 for tubular and rectangular pillars
= 0,49 for open sections
S = safety factor
= 2,00 in general
= 1,66 in accommodation area
D. Cantilevers
1. General
1.1 In order to withstand the bending moment arising
from the load P, cantilevers for supporting girders, hatchway
coamings, engine casings and unsupported parts of decks
are to be connected to transverses, web frames, reinforced
main frames, or walls.
1.2 When determining the scantlings of the cantilevers
and the aforementioned structural elements, it is to be taken
into consideration that the cantilever bending moment
depends on the load capacity of the cantilever, the loadcapacity being dependent on the ratio of rigidity of the
cantilever to that of the members supported by it.
1.3 Face plates are to be secured against tilting by
tripping brackets fitted to the webs at suitable distances
(see also Section 3, H.2.).
1.4 Particulars of calculation, together with drawings
of the cantilever construction are to be submitted for
approval.
2. Permissible stresses
2.1 When determining the cantilever scantlings, the
following permissible stresses are to be observed:
.1 Where single cantilevers are fitted at greater
distances:
bending stress:
b = [N/mm2].
125
k
shear stress:
= [N/mm
2
].
80
k
.2 Where several cantilevers are fitted at smaller
distances (e.g. at every frame):
bending stress:
b = [N/mm2].
150
k
shear stress:
= [N/mm2]100
k
equivalent stress:
v = = [N/mm2].2 32
180
k
.3 The stresses in web frames are not to exceed the
values specified in .1 and .2 above.
E. Hatchway Girders and Girders Forming Partof the Longitudinal Hull Structure
1. The scantlings of longitudinal and transverse
hatchway girders are to be determined on the basis of
strength calculations. The calculations are to be based upon
the deck loads calculated according to Section 4, B. and.C.
2. The hatchway girders are to be so dimensioned that
the stress values given in Table 10.1 will not be exceeded.
Table 10.1 Maximum stress values for hatchway
girder
Longitudinal coaming
and girders of the
strength deck
All other
hatchway
girders
upper and lower flanges :
= [N/mm2]
150
k = [N/mm
2]
150
kdeck level:
= [N/mm2]
70
k
3. For continuous longitudinal coamings the combined
stress resulting from longitudinal hull girder bending and
local bending of the longitudinal coaming is not to exceed
the following value:
L+ [N/mm2]
200
k
= local bending stress in the ship's longitudinal
direction
L = design longitudinal hull girder bending stress
according to Section 5, E.4.
4. The equivalent stress is not to exceed the following
value:
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Section 10 - Deck Beams and Supporting Deck Structures E10 - 4
v = [N/mm2]0,8
L
450
230
k
for L< 90 m
= [N/mm2]
230
k
for L 90 m
= 2x
2
y x y 32
x = L+
y = stress in the ship's transverse direction at
intersection points with transverse members
= shear stress
max = [N/mm2].
90
k
The individual stresses and y are not to exceed150/k [N/mm
2].
5. The requirements regarding buckling strength
according to A.3. are to be observed.
6. Weldings at the top of hatch coamings are subject
to special approval.