3D Wind-Load Generator - Awnings

Since version 22, the possibilities of the 3D Wind-Load Generator have been expanded in order to quickly and automatically generate wind load on the structure of Awning type.

The load generation is available for EC-EN (Eurocode). The load for German, French and British National annex (NA)is generated in accordance with the corresponding NA. When "Standard" or any other National Annex different from the German, French and British is selected, wind load is generated according to German National Annex and a warning is given.

New wind data type - Awning

For wind data property, a new type is introduced - Awning, which needs to be selected in order the load is generated correctly for this type of structure.

The wind load is generated on the awnings, which width is less or equal than 10m and which slope is smaller or equal than +/- 10 degrees (applicable for German and French NA). In case the awning does not respect this geometry, wind load is not generated on the awning and a warning is given.

Generated loads

German Annex (or "Standard EN")

The zones geometry and the air pressure coefficients are considered in accordance with DIN EN 1991-1-4/NA:2010-12, NA.V (original and translated in figures below)

Note: the awning width is parameter d₁ as defined in the figure above (needs to be less or equal then 10 m). Height h is considered as the total height of the building.

Values of the C_p,net pressure coefficient according the table NA.V.1 from DIN EN NA (original and translated in figures below):

Note: The C_p,net coefficient as defined in the table (figure above) is in SCIA interpreted as the C_pe coefficient (coefficient of external air pressure). Coefficient of internal air pressure C_pi is for Awning always considered as 0. Hence, the net pressure applied on the structure w_net = q_p(z) * (C_pe - C_pi) is for Awning considered as w_net = q_p(z) * C_pe ; where q_p(z) is the peak pressure dependent on the height z. This is applicable also for other annexes (French, British, as described further below)

Two examples of the loads generated on awnings (numbered #1 - #9) are shown in the figures below, for two different load cases (#A and #B). For all the awnings , there is applied pressure in the load case which considers "+CPE" (load case #A), except of the awning #6, which has slope > 10°, hence no load at all. For load case with "-CPE", there is suction (load case #B).

French Annex

The zones geometry and the air pressure coefficients are considered in accordance with French CNC2M guidelines (BNCM/CNC2M N0380 / REC EC1-CM : Juillet 2017).

Values of the C_p,net (in SCIA C_pe) pressure coefficient are determined according the table:

Differently from German National Annex, with French National Annex when the ratio h₁/h=1, the awning is treated as a roof overhang, hence wind load is generated accordingly and a warning is given.

Example of generated load is provided in the figure below for one load case (direction of wind 0°). There is no load at all on awning #6 due to the slope above 10°, and awning #7 is treated as the roof overhang (because h₁/h=1):

British Annex

When British National Annex is selected, wind load is generated according to PD 6688-1-4:2015, chapter 3.5 "Canopies attached to tall buildings"

In SCIA, height H (figure above) is considered as the total height of the building (including roof). Height h is the height of the awning (the highest coordinate if the awning is in slope).

For awnings (canopies attached to buildings) attached below half-way up the building (h / H < 0.5), the force coefficients (C_pe) in Table 1 of PD 6688-1-4:2015 are used (table below). The coefficients for θ = 0° apply to awning on windward wall and those for θ = 90° apply to canopies fixed to the side walls. Positive values in the table below act downwards.

For awning on leeward side ( θ = 180° ), there is no load generated.

Awnings attached higher than half-way up the building are assessed using the rules for canopies.

The generated load is different from the German annex (or the standard EN). Few examples of generated loads on various awnings (numbered #1 - #9)are shown below (for British annex), with a table which explains reasons why there is no load generated on some of these awnings for specific load cases. The examples are provided for three various load cases (#A - #C). The height of the building H (up to the roof) is 6 m.