The wind load represents the biggest of the horizontal loads when calculating the
stability of a building. It is important to design the building for this load so it does not
tip over. How the wind load is distributed on the stabilizing walls can be calculated in
different ways. In this report some of these methods are investigated. In those
different calculations the walls take different amount of loads depending on their
stiffness, placement or length etc. A reference house was used to appreciate which
calculation method gives the best result.
In method 1 the stiffness ratio between the floor and the walls decides how the
distribution should be made. If the floor is stiffer than the walls, case 1, the loads are
distributed to the walls depending on their stiffness. Stiffer wall means more loads.
But if the walls are stiffer than the floor, case 2, the load will distributed on the walls
like a beam on fixed supports. If the walls and the floor have relatively the same
stiffness, case 3, the load will be distributed proportionally to the section of the
facades carried by the walls.
Method 2 is a simplified method where only the length of the wall decides how much
load it will take. The longer the wall the more loads it will get.
The reference house is then put into a computer based program, FEM-Design, where
every floor in each direction is calculated one by one. This method is considered the
most correct method in this report, and therefore the results from the other
methods compared by this one to check their correctness.
The results from the reference house show that one of the ways to calculate is more
accurate than the others when compared to the model from FEM-Design. One of the
cases from method 1 seems to be the most correct way to calculate, but it is not the
same case as the one using the recommended method based on the stiffness ratio.
Furthermore, the report shows that none of these methods reflect the realistic
distribution fairly enough. They are all missing some aspect that should be into
consideration. In method 1, case 1, the distance between the point of application of
the force and the wall are not considered. And for case 2 and 3, method 1, the
properties of the walls are not taken into account in the calculation. The results show
that both the distance to the point of application of the force and the walls properties
have a big impact on the wind load distribution.
Keywords: Building stability, Wind load distribution, FEM, Stiffness ratio