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 (Cpe10) 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 Cpe10,A = +0,42
- For h/d ≥ 0,5, we read Cpe10,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: Cpe10,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: Cpe10,B = -0,96
- For zone C
We read: Cpe10,C = -0,40
In the end:
For zone A => Cpe10,A = +0,25
For zone B => Cpe10,B = -0,96
For zone C => Cpe10,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 Cpe value can even be displayed with a dedicated annotation:
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.