LST-EN

LST-EN1990(Category, SubCategory, SubSubCategory, Period)

Probability factor Cprob according to LST-EN1990

Parameters:

Category	-	category of use
SubCategory	-	subcategory of use
SubSubCategory	-	subsubcategory of use
Period	-	reference period [years]

Returns: Cprob

The probability factor is calculated according to the formula Cprob formula

derived from EN1991-1-4 formula 4.2. The formula allows to calculate probability factors for a short reference period (even for a one-year period). For a longer reference period it gives the same results as the formula 4.2.

EN1991-1-1#5.2(Group, Material, Type)

Nominal density for construction materials according to EN1991-1-1#5.2, Annex A1, Fig. A1-A7

Parameters:

Group	-	construction materials group
Material	-	construction material
Type	-	minimal/maximal dead load for selected construction material

Returns: nominal density D [kN/m³]

LST-EN1991-1-1#6.3(Category, SubCategory, SubSubCategory, Type, Load, Value, Period)

Static characteristic values of imposed loads: concentrated load fk, distributed load qk according to LST-EN1991-1-1#6.3

Parameters:

Category	-	category of use
SubCategory	-	subcategory of use
SubSubCategory	-	subsubcategory of use
Type	-	min/default/max imposed load
Load	-	concentrated /distributed imposed load
Value	-	uniformly distributed load qk [kN/m²] or concentrated load Qk [kN]
Period	-	reference period [years]

Returns: fk [kN], qk [kN/m²]

Dynamic characteristic values of imposed loads:

fk=fk*Cprob, qk=qk*Cprob

LST-EN1991-1-1#6.3.1.2(Category, SubCategory, SubSubCategory, N)

Reduction factor alfa_n for loaded areas according to LST-EN1991-1-1#6.3.1.2

Parameters:

Cat	-	category of use
SubCat	-	subcategory of use
SubSubCategory	-	subsubcategory of use
N	-	number of storeys (> 2) above the loaded structural elements from the same category

Returns: alfa_n

LST-EN1991-1-3#4.1(A, Zone, Region)

Characteristic value of snow load on the ground Sk according to LST-EN1991-1-3#4.1

Parameters:

Region	-	European climatic region
Zone	-	zone number given on the map
A	-	site altitude above sea level [m]

Returns: Sk [kN/m²]

Ground snow load Sn [kN/m²] according to return period:

Sn=Sk*Cprob

LST-EN1991-1-3#5.2.7(Topography)

Exposure coefficient Ce for determining the snow load on roofs according to LST-EN1991-1-3#5.2(7)

Parameters:

Topography

-

different topography: windswept, normal, sheltered

Returns: Ce

LST-EN1991-1-3#5.2.8()

Thermal coefficient Ct used to account for the reduction of snow loads on roofs with high thermal transmittance (> 1 W/m²K) according to LST-EN1991-1-3#5.2(8)

Parameters:

none

Returns: Ct=1

LST-EN1991-1-3#5.3(Roof, Alfa, Mu, H, B1, B2, MuMax, Sk)

Roof shape coefficient Mu according to LST-EN1991-1-3#5.3

Parameters:

Roof	-	roof type
Alfa	-	roof inclination angle [°]
Mu	-	snow load shape coefficient: Mu1 or Mu2
H	-	numerical value of vertical dimension [m]
B1	-	distance length [m]
B2	-	distance length [m]
MuMax	-	max(Mu1;Mu2)
Sk	-	characteristic snow load on the ground [kN/m²]

Returns: Mu

EN1991-1-3#D.1(V, Period)

Probability factor Cprob according to EN1991-1-3#D.1

Parameters:

V	-	coefficient of variation of annual maximum snow load
Period	-	reference period [years]

Returns: Cprob

LST-EN1991-1-4#4(Z, Category, Region, Vb0, C0)

Peak velocity pressure Qp according to LST-EN1991-1-4#4

Parameters:

Z	-	height above ground [m]
Category	-	terrain category
Region	-	region in the Netherlands given on the map
Vb0	-	fundamental value of basic wind velocity [m/s]
C0	-	orography factor

Returns: Qp [kN/m²]

Combination value of peak velocity pressure Qp [kN/m²] according to LST-EN1991-1-4#4:

Qp=Qp*Cprob

LST-EN1991-1-4#4.1(Region)

Basic wind velocity Vb according LST-EN1991-1-4#4.2(4.1)

Parameters:

Region

-

terrain category

Returns: Vb [m/s]

LST-EN1991-1-4#4.2(Period, Region, K, N)

Probability factor Cprob according to LST-EN1991-1-4#4.2(4.2)

Parameters:

Period	-	reference period [years]
Region	-	European climatic region
K	-	shape parameter depending on the coefficient of variation of the extreme-value distribution
N	-	exponent

Returns: Cprob

LST-EN1991-1-4#4.4(Cat, Z)

Roughness factor Cr accounting for the variability of the mean wind velocity at the side of the structure according to LST-EN1991-1-4#4.3.2(4.4)

Parameters:

Cat	-	terrain category
Z	-	height above ground level [m]

Returns: Cr

LST-EN1991-1-4#4.6(Category, Vb)

Standard deviation of the turbulence Sigmav according to LST-EN1991-1-4#4.4(4.6)

Parameters:

Category	-	terrain category
Vb	-	basic wind velocity [m/s], defined as a function of wind direction and time of year at 10m above ground of terrain category 2

Returns: Sigmav

LST-EN1991-1-4#4.8(Iv, Vm)

Peak velocity pressure Qp according to LST-EN1991-1-4#4.5(4.8)

Parameters:

Iv	-	wind turbulence intensity according to NEN-EN1991-1-4#4.4
Vm	-	mean wind velocity [m/s]

Returns: Qp

LST-EN1991-1-4#6(B, h, h1, Delta, N1x, Category, Region, Vb0, C0)

Structural factor CsCd according to LST-EN1991-1-4#6

Parameters:

B	-	B² - background factor allowing for the lack of full correlation of the pressure on the structure surface, B=sqrt(B²)
h	-	structure height [m]
h1	-	height [m] General shapes of structures covered by the design procedure. The structural dimensions and the reference height used are also shown:
Delta	-	logarithmic decrement of damping
N1x	-	fundamental frequency of along wind vibration [Hz]
Category	-	terrain category
Region	-	region in Lithuania given on the map
Vb0	-	fundamental value of basic wind velocity [m/s]
C0	-	orography factor

Returns: CsCd

LST-EN1991-1-4#7.2(Roof, Zone, Direction, Param, First)

External pressure coefficient Cpe for buildings and parts of buildings according to LST-EN1991-1-4#7.2

Parameters:

Roof	-	roof type
Zone	-	wind zone
Direction	-	wind direction [°]
Param	-	roof inclination angle [°] h/d - structure height and depth ratio hp/h - parapets height and structure height ratio r/h - eave edge radius and structure height ratio
First	-	for first=false - the pressure changes between two values, so both values are given for first=true - is given single pressure value

Returns: Cpe

EN1991-1-4#7.2.9(Cpe, Openings, Over)

Internal pressure coefficient Cpi for buildings with dominant face according to EN1991-1-4#7.2.9

Parameters:

Cpe

-

external pressure coefficient at the openings in the dominant face

Openings

-

0.0x - for buildings without a dominant face

2.0x - for buildings with a dominant face, when the area of the openings at the dominant face is twice the area of the openings in the remaining faces

3.0x - for buildings with a dominant face, when the area of the openings at the dominant face is at least 3 times the area of the openings in the remaining faces

Over

-

Overpressure: True/False

Returns: Cpi

LST-EN1991-1-4#7.3(Roof, Zone, Blockage, Angle, Downwards, HD)

Net pressure coefficient Cpnet for canopy roofs according to LST-EN1991-1-4#7.3

Parameters:

Roof	-	canopy roof type
Zone	-	wind zone
Blockage	-	degree of blockage under a canopy roof: maximum all phi minimum phi=0 represents an empty canopy minimum phi=1 represents the canopy fully blocked with contents to the down wind eaves only
Angle	-	roof inclination angle [°]
Downwards	-	acting downward wind
HD	-	ratio h1/d1, where h1 - canopy height [m], d1 - canopy dimension [m] along wind

Returns: Cpnet

EN1991-1-4#7.5(Surface)

Friction coefficient Cfr for walls and roof surfaces according to EN1991-1-4#7.5

Parameters:

Surface

-

for smooth surface (i.e. steel, smooth concrete) Cfr=0.01

for rough surface (i.e. rough concrete, tar-boards) Crf=0.02

for very rough surface (i.e. ripples, ribs, folds) Cfr=0.04

Returns: Cfr

LST-EN1991-1-4#B.1(Category, Z)

Turbulent length scale L representing the average gust size for natural winds according to LST-EN1991-1-4#B.1(B.1)

Parameters:

Category	-	terrain category
Z	-	height above ground level [m]

Returns: L [m]