BASIS OF STRUCTURAL DESIGN

(EN1990:2002)

Ultimate limit state verification

(EN1990,cl.6.4.1(1)P)

The following ultimate limit states shall be verified as relevant:

EQU: Loss of equilibrium of the structure, (considering for sliding, overturning or uplift)

STR: Internal failure or excessive deformation of the structure of structural member (Design of structural for

strength of members and frames),

GEO: Failure due to excessive deformation of the ground (Design of structural members such as footing,

piles, basement walls, etc.),

FAT: Fatigue failure of the structure or structural member.

Design working life

(CYS NA EN1990,Table 2.1)

Design working life

category

Indicative design

working life (years)

Examples

1 10 Temporary structures (1)

2 10 – 25 Replaceable structural parts, e.g. gantry girders,

bearings

3 15 – 30 Agricultural and similar structures

4 50 Building structures and other common structures

5 100 Monumental building structures, bridges, and other

civil engineering structures

(1) Structures or parts of structures that can be dismantled with a view to being re-used should

not be considered as temporary.

In the case of replaceable structural parts the design life for the structural determination of loads should be

the design life of the structure.

Design Working life

Ultimate Limit State (ULS)

Ultimate Limit State Concern

(EN1990,cl.3.3(1)P)

Safety of people,

Safety of the structure

Protection of the contents

Design situations

(EN1990,cl.3.2(2)P)

Persistent design situation: Normal use condition

Transient design situation: Temporary condition, e.g. during execution or repair

Accidental design situation: Exceptional condition, e.g. fire, explosion, impact.

Seismic design situation: Structure subject to seismic events.

Ultimate Limit State (ULS)

COMBINATION OF ACTIONS FOR PERSISTENT/TRANSIENT DESIGN SITUATION

(EN1990,cl.6.4.3.2)

Persistent and transient design situation – EQU Equation 6.10 (Set A)

6.10 Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2

Action Favourable

γ

Unfavourable

γ

Permanent (dead,

earth), γG 0.9 1.1

Variable (imposed,

wind), γQ 0 1.5

Note: Single source is not applicable for EQU design situation. Different γ factors can be used in favourable and unfavourable

areas.

Persistent and transient design situation – STR/GEO Equation 6.10, 6.10a & 6.10b (Set B)

6.10

6.10a

6.10b

Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2

Ed=ΣξγG Gk +γQ ψ0,1 Qk1 + γQ ψ0,2 Qk2

Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2

Action Favourable

γ

Unfavourable

γ

Permanent (dead,

earth), γG 1.0 1.35

Variable (imposed,

wind), γQ 0 1.5

Note: Single source is applicable for STR/GEO design situation.

Persistent and transient design situation – GEO Equation 6.10 (Set C)

6.10 Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2

Action Favourable

γ

Unfavourable

γ

Permanent (dead,

earth), γG 1.0 1.0

Variable (imposed,

wind), γQ 0 1.3

Note: Single source is applicable for STR/GEO design situation.

Important notes

(EN1990,cl.3.2(2)P)

Approach 2 (CYS NA EN1990,Table.A1.2(B)) should be used for the

design of the structural members of substructure (i.e. footings, piles,

basement walls, etc.) (CYS NA EN1990,cl. 2.2.3.4).

Actions that cannot exist simultaneously due to physical of functional

reasons should not be considered together in combination.

The use of expression 6.10a and 6.10b lead to a more economic

design in most circumstances.

Summary table of partial, combination and reduction factors for the STR and GEO ultimate limit states for

buildings

Expression

Unfavourable Permanent action Unfavourable Variable actions

Self-weight Imposed floor loads Wind loads Snow loads

6.10

γG=1.35 γQ,1 =1.5 γQ,iψ0,i =1.5x05=0.75 γQ,iψ0,i =1.5x05=0.75

γG=1.35 γQ,iψ0,i =1.5x07=1.05 γQ,1 =1.5 γQ,iψ0,i =1.5x05=0.75

γG=1.35 γQ,iψ0,i =1.5x07=1.05 γQ,iψ0,i =1.5x05=0.75 γQ,i =1.5

Less favourable equations 6.10a & 6.10b

6.10a

γG=1.35 γQ,iψ0,i =1.5x07=1.05 γQ,iψ0,i =1.5x05=0.75 γQ,iψ0,i =1.5x05=0.75

γG=1.35 γQ,iψ0,i =1.5x07=1.05 γQ,iψ0,i =1.5x05=0.75 γQ,iψ0,i =1.5x05=0.75

γG=1.35 γQ,iψ0,i =1.5x07=1.05 γQ,iψ0,i =1.5x05=0.75 γQ,iψ0,i =1.5x05=0.75

6.10b

ξγG=0.85*1.35 γQ,1 =1.5 γQ,iψ0,i =1.5x05=0.75 γQ,iψ0,i =1.5x05=0.75

ξγG=0.85*1.35 γQ,iψ0,i =1.5x07=1.05 γQ,1 =1.5 γQ,iψ0,i =1.5x05=0.75

ξγG=0.85*1.35 γQ,iψ0,i =1.5x07=1.05 γQ,iψ0,i =1.5x05=0.75 γQ,i =1.5

Note: Shaded boxes indicate the ‘leading variable action’,

Combination (sensitivity) factor, ψ

(CYS NA EN1990:2002, Table A1.1)

Category Specific Use ψο ψ1 ψ2

A Domestic and residential 0.7 0.5 0.3

B Office 0.7 0.5 0.3

C Areas for Congregation 0.7 0.7 0.6

D Shopping 0.7 0.7 0.6

E Storage 1.0 0.9 0.8

F Traffic < 30 kN vehicle 0.7 0.7 0.6

G Traffic < 160 kN vehicle 0.7 0.5 0.3

H Roofs 0.7 0 0

Snow, altitude < 1000 m 0.5 0.2 0

Wind 0.5 0.2 0

Serviceability Limit State (SLS)

COMBINATION OF ACTIONS FOR SERVICEABILITY LIMIT STATE

(EN1990,cl.6.5.3)

Characteristic combination

Equation 6.14b Ed=Gk +Qk,1 + ψ0 Qk,2

Frequent combination

Equation 6.15b

Ed=Gk + ψ1Qk,1 + ψ2 Qk,2

Quasi-permanent combination

Equation 6.16b

Ed=Gk + ψ2Qk,1

Characteristic value of variable actions

For each variable action there are four representative values:

1.The characteristic value Qk (determine by insufficient data).

2.The combination value ψ0Qk (of an action is intended to take account of the

reduced probability of the simultaneous of two or more variable actions).

3. Frequent value ψ1Qk (exceeded only for a short period of time and is used

primary for the SLS and also the accidental ULS).

4. Quasi-permanent value ψ2Qk (exceeded for a considerable period of time or

considered as an average loading over time and used for the long-term affects

at the SLS and also accidental and seismic ULS).

INDICATIVE LIMITING VALUES FOR VERTICAL DEFLECTIONS

(Manual of EC0 &EC1, Table D.1)

Serviceability Limit States

Vertical deflections

Serviceability Requirement Characteristic Combination (Expression 6.14b

in EC0) wmax

Function and damage to non-

structural elements (e.g.

partition walls claddings etc)

–Brittle

-Non-brittle

Function and damage to

structural elements

≤L/500 to L/360

≤L/300 to L/200

≤L/300 to L/200

Serviceability Limit State (SLS) – Vertical and Horizontal deformations

INDICATIVE LIMITING VALUES FOR HORIZONTAL DEFLECTIONS

(Manual of EC0 &EC1, Table D.2)

Serviceability Limit States

Vertical deflections

Serviceability Requirement Characteristic Combination (Expression 6.14b

in EC0) wmax

Function and damage to non-

structural elements

–Single storey buildings top

of column

-Each storey in a multi-storey

building

-The structure as a whole for

a multi-storey building

u≤H/300

u≤H/500 to H/300

u≤H/500

Category of use

(EN1991-1-1:2002,Table 6.1)

Category Specific Use Example

A Area for domestic and

residential activities

Rooms in residential buildings and houses bedrooms and wards in

hospitals, bedrooms in hotels and hostels kitchens and toilets

B Office areas

C Areas where people may

congregate (with the

exception of areas

defined under category

A, B, and D1))

C1: Areas with tables, etc. e.g. areas in schools, cafés, restaurants,

dining

halls, reading rooms, receptions.

C2: Areas with fixed seats, e.g. areas in churches, theatres or

cinemas, conference rooms, lecture halls, assembly halls, waiting

rooms, railway waiting rooms.

C3: Areas without obstacles for moving

people, e.g. areas in museums, exhibition rooms, etc. and access

areas in public and administration buildings, hotels, hospitals,

railway station forecourts.

C4: Areas with possible physical activities, e.g. dance halls,

gymnastic rooms, stages.

C5: Areas susceptible to large crowds, e.g. in buildings for public

events like concert halls, sports halls including stands, terraces and

access areas and railway platforms.

D Shopping areas D1: Areas in general retail shops

D2:Areas in departments stores

Imposed loads

(EN 1991-1-1:2002, Table 6.2)

Category Of loaded areas qk

(kN/m2)

Qk

(kN)

Category A

-Floors

-Stairs

-Balconies

Category B

Category C

-C1

-C2

-C3

-C4

-C5

Category D

-D1

-D2

1.5-2.0

2.0-4.0

2.5-4.0

2.0-3.0

2.0-3.0

3.0-4.0

3.0-5.0

4.5-5.0

5.0-7.5

4.0-5.0

4.0-5.0

2.0-3.0

2.0-4.0

2.0-3.0

1.5-4.5

3.0-4.0

2.5-7.0

4.0-7.0

3.5-7.0

3.5-4.5

3.5-7.0

3.5-7.0

Imposed load on Roof

(CYS NA EN1991-1-1, Table 6.10)

Sub-category Actions

Imposed load,

qk

(kN/m2)

Q (kN)

H Roof (inaccessible except for

normal maintenance and repair) 0.4 1.0

STRUCTURAL LOADS

(EN1991:2002)

Imposed Loads

Permanent load

(EN 1991-1-1:2002, Table A.1-A.12)

Materials Density, γ

(kN/m3)

Modulus of

Elasticity, E

kN/mm2

Reinforced Concrete

Steel

Glass

Water

Plastic PTFE

Softwood timber

Hardwood timber

Concrete blockwork

Asphalt

Roof tiles

Soil (Sand)

Soil (Clay)

Insulation board

Aluminium

Copper

Cement mortar

Νylon

Epoxy resin

Polystyrene

Carbon fibre

Fibre glass

Granite

25

78

25

10

21-22

5

7

18

22

20

16-18

20-22

3

27

87-89

19-23

11.5

16-20

10-13

20

15

26

17-31

210

74

-

0.3-0.6

10

12

-

-

5-30

-

-

-

69

96

20-31

2-3.5

20

3-3.3

415

10

40-70

Permanent Loads

Typical unit floor Typical loadings Typical unit floor Typical loadings

Steel floor kN/m2

Self weight of beam 0.25

Self weight of decking 0.10

Self weight of meshing 0.05

Ceiling and services 0.15

Total 0.55

Internal ConcreteFloor kN/m2

Partition (minimum) 1.00

Screed (5-70cm) 1.20-1.80

Raised floor 0.40

Concrete floor (15cm) 3.75

Celling and services 0.15

Total 6.50-7.10

External Concrete Floor kN/m2

Slabs / paving 0.95

Screed (50cm) 1.20

Asphalt waterproofing 0.45

Concrete floor (15cm) 3.75

Celling and services 0.15

Total 6.50

Metal deck roofing kN/m2

Live loading: snow/

wind uplift 0.6-1.0

Outer covering, insulation and

metal deck liner 0.30

Purlins-150 deep at 1.5m c/c 0.10

Services 0.10

Total 1.1-1.5

Timber Floor kN/m2

Partition 1.00

Timber boards/plywood 0.15

Timber joist 0.20

Celling and services 0.15

Total 1.50

Timber Flat Roof kN/m2

Asphalt waterproofing 0.45

Timber joist and insulation 0.20

Celling and services 0.15

Total 0.80

GENERAL LOAD ON SLABS (kN/m2)

Material Actions,

gk

(kN/m2)

Paving

Waterproofing

Insulation (polysterini)

Suspended selling

Services

Carpet

Steel clad steel frame

Masonry clad concrete frame

Masonry clad timber frame

Masonry clad steel frame

1.00

0.50

0.10

0.15

0.30

0.03 5-10

20-25

10-15 15-20

SNOW LOAD

(EN1991-1-3)

Snow load on roof for transient design situations

s=μiCeCtsk

(EN 1991-1-3Equ.5.1)

Snow load shape coefficients, μ

(EN1991-1-3, Table 5.2)

Angle of pitch of

roof, a

0ο≤α≤30

ο 30

ο≤α≤60

ο α≥60

ο

μ1 0.8 0.8(60-α)/30 0

μ2 0.8+0.8 α/30 1.6 -

For monopitch roof use only μ1

For pitched roof use μ1andμ2

THERMAL COEFFICIENTS C

(ΕΝ1991-1-3¨2003, cl. 5.2(8))

Ct=1.0

Thermal transmission on the roof

<1W/m2K

Exposure coefficient(ΕΝ1991-1-3, Table 5.1)

Topography Ce

Windswept

0.8

Normal

1.0

Sheltered

1.2

CHARACTERISTIC SNOW LOAD

ON GROUND,sk (kN/m2)

(CYS NA ΕΝ1991-1-3, cl. NA 2.7)

sk = 0.289*(1+(A/452)2)

A:is the attitude above sea level (m)

Snow load shape coefficients for cylinder roofs, μ

(EN1991-1-3, Eq. 5.4-5.5)

μ1 0.8 μs=0

a≤15o

μ2 μs+μw

μw=(b1+b2)/2h ≤ γh/sk Range must:0.8≤μw≤4

γ:is the weight density of snow may taken as 2kN/m3

Angle of pitch of roof, a β>60ο

β≤60

μ3 should be less than μ3≤2 0 0.2+10 h/b

Monopitch roof Pitch roof Cylinder roof

WIND LOAD

(EN1991-1-4)

Fundamental Basic wind velocity, vb,0

(CYS NA EN1991-1-4,Fig.1)

Directional factor

(CYSEN1991-1-4,NA 2.4)

cdir=1.0

(Conservative value for all direction)

Season factor

(CYS EN1991-1-4,NA 2.4)

cseason=1.0

Basic wind velocity

(EN1991-1-4, Eq. 4.1)

vb=cdir.cseasonvb,0

BASIC WIND VELOCITY

STRUCTURAL FACTOR

(EN1991-1-4, cl.6.0)

cscd =1.0

Builiding with less than

h≤15m

Natural frequency

f≤5Hz

Walls≤100m high Chimney with circular

cross-sectional area and,

h≤60m

h≤6.5·diameter

h

Determination of cscd

Determine of structural factor cscd

Size factor

(EN1991-1-4,Eq.6.2)

It is on the safe side to use

B2=1 kp=3

Calculation of R2 can be found in Annex B of

EN1991-1-4:2005

Can be found

Dynamic factor

(EN1991-1-4,Eq.6.3)

It is on the safe side to use

B2=1 kp=3

Calculation of R2 can be found in Annex B of

EN1991-1-4:2005

Consider Ignore

Upwind Slope≤3o

NO YES

TERRAIN OROGRAPHY,

(EN1991-1-4, cl.4.3.3)

Detail calculation of terrain orography

factor can be found in Annex A of

EN1991-1-4:2005

PEAK VELOCITY PRESSURE

Roughness factor, cr(z)

(EN1991-1-4,Eq.4.3-4.5)

cr(z)=kr . ln(z/z0) for zmin≤z≤zmax

cr(z)=cr . (zmin) for z≤zmin

z0: is the roughness length

Maximum height, zmax

(EN1991-1-4, cl. 4.3.2)

zmax=200m

Orography factor co(z)

co(z)=1

Terrain factor,

(EN1991-1-4,cl.4.4)

kr=0.19(z0/z0,II)0.07

Mean wind velocity, vm(z)

(EN1991-1-4 cl.4.3.1 )

vm(z)=cr(z).co(z).vb

Wind turbulence, Iv(z)

(EN1991-1-4,Eq.4.7)

Iv(z)=σv/vm(z)=kl/co(z)ln(z/z0) for

zmin≤z≤zmax

Iv(z)=Iv(zmin) for z≤zmin

Turbulence factor: kl=1.0

(NA CYS EN1991-1-4, cl. NA 2.10)

Note: for co(z)=1 Iv(z) is not important

Peak velocity pressure, qpeak(z)

(EN1991-1-4 Eq.4.8 )

qpeak(z)=[1+7 Iv(z)]0.5ρ vm2

(z)=ce(z)·0.5·ρ·vb2

Air density:ρ=1.25kg/m3

Terrain category and terrain parameters (EN1991-1-4, Tab.:4.1)

Terrain

category

Description z0 (m) zmin(m)

0 Sea, costal area exposed to the open

sea. SEA 0.003 1

I Lakes or area with negligible

vegetation and without obstacles.

COUNTRY

0.01 1

II

Area with low vegetation such as

grass and isolated obstacles trees,

buildings) with separations of at least

20 obstacle height.

0.05 2

III

Area with regular cover of vegetation

or buildings or woth isolatd obstacles

with seperations of maximum 20

obstacle height (such as villages,

suburban terrain, permanent forest). TOWN

0.3 5

IV*

Area in which at least 15% of the

surface is covered with building and

their average height exceeds 15m.

1.0 10

* For buildings in terrain category IV, displacement height hdis should be consider and information can be found in Aneex A.5 of EN1991-1-4:2005

Values of external pressure coefficient for vertical walls of rectangular plan buildings

(EN1991-1-4, Tab.:4.1)

ZONE A B C D E

h/d cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

5 -1.2 -1.4 -0.8 -1.1 -0.5 +0.8 +1.0 -0.7

1 -1.2 -1.4 -0.8 -1.1 -0.5 +0.8 +1.0 -0.5

≤0.25 -1.2 -1.4 -0.8 -1.1 -0.5 +0.7 +1.0 -0.3

Note: Values for cpe,1 are intended for the design of small elements and fixings with an element of 1m2 or

less such as cladding elements and roofing elements. Values for cpe,10 may be used for the design of the

overall load bearing structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for

loadaded area of 1m2 and 10m

2 respectively.

Reference height ze, depending on h and b, and corresponding velocity pressure profile

(EN1991-1-4, Fig. 7.4)

Key for vertical walls – Flat Roof

(EN1991-1-4, Fig.7.5)

Key for vertical walls –Mono&dual pitch

Roof

(EN1991-1-4, Fig.7.5)

Pressure on surface &Wind force (EN1991-1-4, Eq. 5.1&5.5)

we=qp(ze).(cpe +cpi) & Fw=cscd·Σwe·Aref

EXTERNAL WIND PRESSURE/FORCE ON WALLS

EXTERNAL WIND PRESSURE/FORCE ON FLAT ROOF

Recommended values of external pressure coefficients for flat roofs

(EN1991-1-4,Tab. 7.2)

Roof type

Zone

F G H I

cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

Sharp eaves -1.8 -2.5 -1.2 -2.0 -.07 -1.2 +0.2

With

Parapets

hp/h=0.025 -1.6 -2.2 -1.1 -1.8 -0.7 -1.2 -0.2

hp/h=0.05 -1.4 -2.0 -0.9 -1.6 -0.7 -1.2 +0.2

hp/h=0.10 -1.2 -1.8 -0.8 -1.4 -0.7 -1.2 -0.2

Curved

Eaves

r/h=0.05 -1.0 -1.5 -1.2 -1.8 -0.4 +0.2

r/h=0.10 -0.7 -1.2 -0.8 -1.4 -0.3 -0.2

r/h=0.20 -0.5 -0.8 -0.5 -0.8 -0.3 +0.2

Mansard

Eaves

a=30o

-1.0 -1.5 -1.0 -1.5 -0.3 -0.2

a=45o -1.2 -1.8 -1.3 -1.9 -0.4 +0.2

a=60o -1.3 -1.9 -1.3 -1.9 -0.5 -0.2

Note: Values for cpe,1 are intended for the design of small elements and fixings with an element of 1m2 or

less such as cladding elements and roofing elements. Values for cpe,10 may be used for the design of the

overall load bearing structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for

loadaded area of 1m2 and 10m

2 respectively.

Pressure on surface &Wind force (EN1991-1-4, Eq. 5.1&5.5)

we=qp(ze).(cpe +cpi) & Fw=cscd·Σwe·Aref

Recommended values of external pressure coefficients for monopitch roofs

(EN1991-1-4,Tab. 7.3a)

Pitch

Angle

a

Zone for wind direction θ=0o Zone for wind direction θ=180

o

F G H F G H

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1 cpe,10 cpe,1

5o -1.7 -2.5 -1.2 -2.0 -0.6 -1.2 -2.3

-2.5 -1.3 -2.0 -0.8 -1.2 +0.0 +0.0 +0.0

15o -0.9 -2.0 -0.8 -1.5 -0.3

-2.5 -2.8 -1.3 -2.0 -0/9 -1.2 +0.2 +0.2 +0.2

30o -0.5 -1.5 -0.5 -1.5 -0.2

-1.1 -2.3 -0.8 -1.5 -0.8 +0.7 +0.7 +0.4

45o -0.0 -0.0 -0.0

-0.6 -1.3 -0.5 -0.7 +0.7 +0.7 +0.6

60o

+0.7 +0.7 +0.7 -0.5 -1.0 -0.5 -0.5

75o

+0.8 +0.8 +0.8 -0.5 -1.0 -0.5 -0.5

Recommended values of external pressure coefficients for monopitch roofs

(EN1991-1-4,Tab. 7.3b)

Pitch

Angle

a

Zone for wind direction θ=90o

Fup Flow G H I

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1

5o

-2.1 -2.6 -2.1 -2.4 -1.8 -2.0 -0.6 -1.2 -0.5

15o -2.4 -2.9 -1.6 -2.4 -1.9 -2.5 -0.8 -1.2 -0.7 -1.2

30o -2.1 -2.9 -1.3 -2.0 -1.5 -2.0 -1.0 -1.3 -0.8 -1.2

45o -1.5 -2.4 -1.3 -2.0 -1.4 -2.0 -1.0 -1.3 -0.9 -1.2

60o -1.2 -2.0 -1.2 -2.0 -1.2 -2.0 -1.0 -1.3 -0.7 -1.2

75o -1.2 -2.0 -1.2 -2.0 -1.2 -2.0 -1.0 -1.3 -0.5

Note: Values for cpe,1 are intended for the design of small elements and fixings with an element of 1m2 or less such

as cladding elements and roofing elements. Values for cpe,10 may be used for the design of the overall load bearing

structure of buildings. The external pressure coeffiecient cpe,1 and cpe,10 is using for loadaded area of 1m2 and 10m

2

respectively.

EXTERNAL WIND PRESSURE/FORCE ON MONOPITCH ROOF

Pressure on surface &Wind force (EN1991-1-4, Eq. 5.1&5.5)

we=qp(ze).(cpe +cpi) & Fw=cscd·Σwe·Aref

Recommended values of external pressure coefficients for duopitch roofs

(EN1991-1-4,Tab. 7.4a)

Pitch

Angle

a

Zone for wind direction θ=0o

F G H I J

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,1

-45o

-0.6 -0.6 -0.8 -0.7 -1.0 -1.5

-30o

-1.1 -2.0 -0.8 -1.5 -0.8 -0.6 -0.8 -1.4

-15 o -2.5 -2.8 -1.3 -2.0 -0.8 -1.2 -0.5 -0.7 -1.2

-5 o -2.3 -2.5 -1.2 -2.0 -0.8 -1.2

+0.2 +0.2

-0.6 -0.6

5 o

-1.7 -2.5 -1.2 -2.0 -0.6 -1.2 -0.6

+0.2

+0.0 +0.0 +0.0 -0.6

15 o

-0.9 -2.0 -0.8 -1.5 -0.3 -0.4 -1.0 -1.5

+0.2 +0.2 +0.2 +0.0 +0.0 +0.0

30 o

-0.5 -1.5 -0.5 -1.5 -0.2 -0.4 -0.5

+0.7 +0.7 +0.4 +0.0 +0.0

45 o

-0.0 -0.0 -0.0 -0.2 -0.3

+0.7 +0.7 +0.6 +0.0 +0.0

60 o +0.7 +0.7 +0.7 -0.2 -0.3

75 o +0.8 +0.8 +0.8 -0.2 -0.3

Recommended values of external pressure coefficients for duopitch roofs

(EN1991-1-4,Tab. 7.4b)

Pitch

Angle a

Zone for wind direction θ=90o

F G H I

cpe,10 cpe,1 cpe,10 cpe,10 cpe,1 cpe,10 cpe,10 cpe,1

-45o

-1.4 -2.0 -1.2 -2.0 -1.0 -1.3 -0.9 -1.2

-30o -1.5 -2.1 -1.2 -2.0 -1.0 -1.3 -0.9 -1.2

-15o -1.9 -2.5 -1.2 -2.0 -0.8 -1.2 -0.8 -1.2

-5o -1.8 -2.5 -1.2 -2.0 -0.7 -1.2 -0.6 -1.2

5o -1.6 -2.2 -1.2 -2.0 -0.7 -1.2 -0.6

15o -1.3 -2.0 -1.2 -2.0 -0.6 -1.2 -0.5

30o -1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

45o -1.1 -1.5 -1.4 -2.0 -0.9 -1.2 -0.5

60o -1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

75o -1.1 -1.5 -1.4 -2.0 -0.8 -1.2 -0.5

EXTERNAL WIND PRESSURE/FORCE ON DUOPITCH ROOF

Pressure on surface &Wind force (EN1991-1-4, Eq. 5.1&5.5)

we=qp(ze).(cpe +cpi) & Fw=cscd·Σwe·Aref