The present article explains how to determine wind loads on vaulted roofs at the Eurocode 1. Specifically, we will show how to use Figure 7.11 from EN1991-1-4, which provides the external pressure coefficients on vaulted roofs with rectangular base:

We will consider a structure with following dimensions:

f = 2,51m

h = 3,20m

d = 9,60m

The developed length of the vaulted roof will be split into 4 equal parts, for zone A, zone B (repeated twice) and zone C:

For each of these zones, the external pressure coefficient (C_pe10) is read on a graph, depending on the f/d and h/d ratios.

In our case:

f/d = 2,51 / 9,60 = 0,26

h/d = 3,20 / 9,60 = 0,33

• For zone A

We start on the f/d axis until we reach the two diagrams related to zone A:

• For h/d = 0, we read C_pe10,A = +0,42
• For h/d ≥ 0,5, we read C_pe10,A = +0,16

We then perform a linear interpolation because in our case, 0 ≤ h/d ≤ 0,5:

For h/d = 0,33, we get: C_pe10,A = +0,25

• For zone B

We start on the same position on f/d axis, but this time, we reach the zone B diagram.

We read: C_pe10,B = -0,96

• For zone C

We read: C_pe10,C = -0,40

In the end:

For zone A => C_pe10,A = +0,25

For zone B => C_pe10,B = -0,96

For zone C => C_pe10,C = -0,40

Starting from version 2021, vaulted roofs at the Eurocode 1 are covered by the climatic generator of Advance Design.

Wind actions, whether 2D or 3D, are instantly generated:

As prescribed in the Eurocde 1, roof is divided into 4 equal zones.

The name of each zone as well as their C_pe value can even be displayed with a dedicated annotation:

Conclusion

The evaluation of wind action on vaulted roofs by reading the graph from the Eurocode 1 can be tedious, with a high risk of error.

Fortunately, in Advance Design, this process is fully automated. Wind forces are created instantly, and they can be updated in a single click whenever a modification is made on the building.