2. Methods

2.1 Equipment
Saw x 1
Glue Gun x 2
Quake Catcher Network (QCN) Sensors x 5
Fig. 3. Five QCN sensors and wires to connect to macbooks.

Macbooks (with Windows software) x 5
60 cm “New Zealand Medium Density Fibre” Wooden Sticks x 255
90 cm “New Zealand Medium Density Fibre” Wooden Sticks x 350
New Zealand Medium Density Fibre” Wooden Base Board x10
Ball Bearings x 1
Net x 1
Book-strap x 2
Cable tie
Bar magnet x 5
Scroll Saw x 1
Bench Drilling Machine x 1
Shake Table x 1
- consisting of:
- Crank Wheel x 1
- Connector (the part which connects the crank wheel to the platform) x 1
- ACDC Converter x 1
- DC Motor x 1
- Cable wire x 1
- Base board (for platform) x 1
- Large wooden board x 1
- Springs x 8
Fig. 4. Voltage Converter.             Fig. 5. DC Motor used to turn the wheel which moves the connector.
Fig. 6. Close up of cable tie connecting shake table platform to the connector.
Fig. 7. Shake table platform supported by springs connected to a large piece of wood.

2.1 Procedures and Diagrams
   Building of the tower
1. Draw a 17x17 square in the middle of the base board.
2. Glue 4 sets of 3 sticks together in the “L” shape.
Fig. 8. L-shaped stick (Step 2).

3. Draw the outline of the “L” shape at the corner of the square.
4. Drill the L shape holes using the bench drilling machine and scroll saw. File the holes in the base board so that it fits the L-shaped sticks.
Fig. 9.  Preparation of base board (Steps 1, 3-4).

5. Glue the 4 sets of 3 sticks into the L shape holes with the help of the 90-degree ruler so that they are perpendicular to the base board.
Fig. 10. Glueing the L shape sticks into the L shape holes (Step 5).
6. Saw the sticks into 17 cm each.
7. Saw 270 18 cm sticks.
8. Glue the 17 cm sticks to the top floor of the tower (top marking on the L-shaped set of 3 sticks) to make the outer frame of the top floor of the tower. This helps to ensure that the tower is straight and perpendicular to the base.
9. Repeat step 8 for the first floor.
10. Use the 18 cm sticks and make the first floor of the tower.
Fig. 11. Straightening the tower and constructing the first floor (Step 8-10).
Fig. 12. Close up of the first floor (Step 10).
11. Repeat steps 9 and 10 for all four levels.
12. Saw the sticks into slanted 19.5 cm pieces each.
13. Glue the sticks onto the tower to make the bracings.
14. Repeat steps 1-13 for the rest of the towers.
Fig. 13. An example of a completed tower.
   Data Collection
1. Place one of the towers on the shake table.
2. Secure it onto the shake table using the book-straps.
3. Connect the 5 QCN sensors to one macbook each and place each of the sensors onto the positions marked on the tower. Secure the sensors using the wooden clips.
Fig. 14. Book-straps are used to secure the tower onto the shake table platform (Step 2).

4. Place the South pole of the bag magnet at the part of the compass where the arrow should be pointing towards. Secure it onto the sensor using double-sided tape. This is done because the compass on the sensors at the bottom floor and the base do not point towards north as there is too much interference. The sensors must be placed in the north orientation so that the X and Y axis will read the correct direction of vibration of the earthquakes in the real situations. Securing the magnet onto the sensor ensures that the compass arrow points towards the direction labeled “North” on the sensor at all times. This ensures that the graph would not be affected by compass interference.
FIg. 15. Top view of magnet on sensor. The arrow on the compass is kept pointing towards the direction labeled north on the sensor (Step 4).
Fig. 16. Example of the set-up.
5. Switch on the shake table and set the voltage source at 12 V. Shake at 12 V for 15 s. The graphs of the shake at each part of the tower will be recorded on the macbook by the sensors.
Fig. 17. Example of a graph generated by QCN during the earthquake simulation (Step 5).
6. Switch off the shake table after 15 s and press the pause button in the software at the same time. Save the graphs as “Earthquake Test_BeamSetNo., BracingName_FFloorNo_TTrialNo.” on each macbook. (eg. Earthquake Test_1,X_F4_T1). For the floor number, 0 will be used for the base while 4 will be used for the top floor. Remove everything that is on the shake table.
7. Repeat Steps 5-6.
8. Place the damper on top of the building and repeat Steps 5-7. Save the graphs as “Earthquake Test_BeamSetNo.,BracingName,Damper_FFloorNo_TTrialNo.”.
9. Repeat steps 1-8 using the rest of the towers, making sure that the positions of the sensors remain constant.

2.3 Risk Assessment and Management
There are several risks involved in the project, especially in the following:
(a) cutting of the wood using the coping saw or drill leading to cuts
(b) gluing of the building structure using the glue gun leading to high temperature burns
Standard lab procedures of making sure that there are preventive measures taken, such as:
(a) using proper vices to hold the item to be sawed or drilled
(b) proper attire and measures such as tying of hair that will prevent accidents
Besides that, first aid materials are also made available in case of any accidents.   

2.4 Data Analysis
1. Look at y-axis of one graph and find the difference between the highest and lowest points within the first 1-second interval. Repeat this for the rest of the 1-second intervals.
2. Find the average difference between the highest and lowest points of the graph by adding up the differences recorded in the previous step and dividing it by the total number of 1-second intervals. Record down this average difference in a table.
3. Repeat steps 1-2 for the graph of the second test and record the result in the table in Step  2.
4. Find the average of these two average differences and record it in the table in Step 2.
5. Using the tables, create bar charts to compare the difference in shake of the three different bracings.
6. Repeat step 5 for beams and the presence of a damper.

7. Based on the bar charts and the comparisons made, conclude how each factor affects the stability of the tower.

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