TESTING

Because balsa wood is not a typical building material, it is necessary to understand the structural properties of the wood.

To do so, a number of small-scale tests were conducted to verify such properties.

This includes a three point bending test, tensile coupon testing, and connections testing, all of which offered valuable insight into the material strength of balsa wood and how the analysis model could be calibrated.

Most importantly, a full-scale shaketable test is also essential for understanding the fundamental vibrational properties of the structure.

Using the small shaketable at the University of Toronto, we are able to perform sine-sweep tests to find the fundamental period as well as the damping ratio of a particular structure.

With this information in hand, we are therefore able to effectively calibrate our analysis model to match the structural properties measured from these tests.



ANALYSIS

Our analysis approach includes using both industry-standard structural analysis software and in-house scripts to visualize the most critically loaded members.

A line model of the structure is first created in SAP2000, which is then used to run linear time history analysis as well as classical modal analysis.


The analysis results from SAP2000 are then exported using a MATLAB and Excel VBA script to independently highlight the members that are loaded most closely to capacity.

This is done by comparing the demand to the measured structural capacity from previous material testing.

*Optimization blurb*



CONSTRUCTION

Construction of the tower entails a great deal of teamwork and dedication.

The key structural members are fabricated and assembled first using a full-height jig as shown below.


Inner structural floor plans and external braces are thereafter added to the structure.

The last step is to add the architectural elements to fulfil the form of the design.

Last but not least, the construction of the shipping crate ensures the structure can be safely transported to the competition site.

2016 EERI SDC

In our inaugural year competing in the EERI Seismic Design Competition, we learned a great deal about constructing and designing a balsa wood structure to withstand ground motions of varying intensities.

Our design this year consisted of an integrated structural and architectural systems in order to blend into the architectural scene of San Francisco.


A total of seven undergraduate engineering students travelled to San Francisco, CA to compete in the 12th Annual EERI Seismic Design Competition alongside top engineering schools from all over the world.

A huge thank you goes out to UBC alumni as well as the graduate students from the University of Toronto for giving us a head start in understanding the competition and structural design!

See below for a summary of our team’s performance:

2017 EERI SDC

This year our team achieved a number of significant milestones in terms of construction and design based on our experience from the previous year.

Firstly, we were able to completely restructure our construction process by employing the use of a full height jig in order to maximize consistency throughout the structure.


With this faster and more efficient construction process, our team was able to construct a full scaled prototype to test at the University of Toronto.

Special thanks goes out to Professor Christopoulos and Professor Kwon for graciously allowing the team to use the shaketable and to Dr. Reza Hessabi for teaching our team on how to operate the shaketable.

The results from these shaketable tests were essential for calibrating our analysis model as well as for deriving the fundamental modal properties of our design.

Once our analysis model had been properly calibrated, we were able to optimize the design of the structure through seeking the most cost-effective cross-sectional width of our tubular design that can still allow for architectural flexibility.

This parametric study was conducted using a script written in Excel VBA alongside the SAP2000 oAPI plugin.

The results of our analysis and collaboration with architectural students accumulated to the design of the Aqua tower.
A total of six engineering undergraduate students travelled to the Portland, OR to compete in the 13th Annual EERI Seismic Design Competition.

It was a pleasure competing alongside some of the top engineering schools from around the world while meeting new and old fellow engineering peers who share the same passion and enthusiasm for seismic engineering as us.
See below for a summary of our team’s performance: