Effect of Wind Load on a Building


The purpose of this experiment was to determine the effect of height to width ratio on the wind load of a building.

I became interested in this idea when I was watching a news report about a hurricane that made some taller buildings fall down while sparing many shorter buildings. People paid lots of money and did extra work to fix them.

The information gained from this experiment could help architects determine how to design buildings of a certain size so the wind has less drag on it. People could get hurt if the wind has too much drag and makes the building fall down.


My hypothesis was that as the height to width ratio increased, the wind load (drag) would increase.

I based my hypothesis on an article from World Book Encyclopedia that was called “Wind Surface.” It said, “That wind can blow so lightly that you can’t even feel it or it can blow so hard that it rips trees out of the ground and can crush buildings.”    


The constants in this study were:

•    The speed of the wind.

•    The size of the wind tunnel. 

•    The time I gave the wind to blow on the structure.

•    The type of material I used to make the structure (plywood). 

•    The surface area of the shape facing the wind. 

•    The shape facing the wind.

•    The unit I used to measure with.

•    The strength of the wind.

•    The size of the wheels.

•    The material the wheels are made of.

•    The number of wheels on each structure.

•    The size of the axels.

•    The number of axels.

•    The material the axels are made of.

•    The size of the axel holes in the wheels.

•    The place where the wind comes out of.

•    The machine the wind comes out of.

•    The size of holes the axels go in the structure.

•    The type of glue I used to glue the structure together.

•    The placing of the structure in the wind tunnel.

The manipulated variable was the height to width ratio of the structures.

The responding variable was the force of drag.

To measure the responding variable, I used a spring scale.  


73cm by 73cm Wind Tunnel
Leaf Blowers
Axel pegs
1 piece of
30cm by 121cm Plywood Board
Electric Wood Saw
1 Bottle
Wood Glue
1 Can
Spray Paint
1 Box
Small Nails
Carpenters Pencil


1)    Build Structures  

A.    Buy a plywood board that is 30in by 121in.

B.    Cut four pieces of board so they are 5 inches by 4 inches then glue and nail the boards together so that one of the faces of the board has an area of 20 inches2.

C.    Put your 16 wheels on the 16 axle pegs. 

D.    Drill a hole in the board that is big enough for the axle peg to go in but small enough so that the peg doesn’t come out easily. Put wood glue around the axle peg’s end so that it will stay inside the hole.

E.    Clamp down on two sides with your clamp.

F.    Screw a metal hook into the front of the structure.

G.    Cut twelve more pieces of wood that have four 4 by 5, four 2 by10, and four10 by 2. Repeat step one with all. 

2)    Move wind tunnel if needed.
A.    If you need to take wind tunnel into a quiet room with no people in it but you and a supervisor. 

III)    Start your experiment.

A.    Put your structures in the wind tunnel one at a time and let the wind blow on them for two minuets every ten seconds write down how many newtons are pushing on the structure.

B.    After you do this for six times with every structure go to each amount of time being a multiple of thirty except zero and find the average newtons of each structure in the multiples of thirty going to one-hundred-twenty.


The original purpose of this experiment was to determine the effect of height to width ratio on the wind load of a building.

The results of the experiment when my structure had a surface of about 20 inches2 having wind blow on my structures for 10 minuets and me recording how many newtons were pulling on the spring scale on my first structure at


My hypothesis was that as the height to width ratio increased, the wind load (drag) would increase.

The results indicate that this hypothesis should be rejected because my results were mixed. My hypothesis said that when the height to width ratio increased so would the wind drag. On my first two structures that was correct. On my last two however it was the exact opposite of that. On my last two structures it was the smaller the height to width ratio the more drag the building had on the wind.  

After thinking about the results of this experiment, I wonder if it matters with other objects such as a car or a plane. 

If I were to conduct this project again I would do the experiment with more trials than I had this. 

Researched by ------ Ben M


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