To Montreal and back again

From November 20th to 21st, I returned to Montreal to do more testing on the bridge in Brossard (now called the Daigneault Creek bridge in literature). Ayan's wireless sensors were ready for testing and I was to go with him because I knew the bridge, knew the testing procedure, and I could drive.

It was a really crazy schedule on the Tuesday since I had class until about noon and then I raced to the car rental place at Weber and Columbia, picked up the car, tossed our equipment in the back (which was nothing compared to the last trip), and picked up Ayan. The only equipment we essentially had was a laptop, two wireless sensors that had 2 axes of measurement, a receiver plugged into the laptop, and double-sided tape. As a side note, this was the first time I got to rent a car since my being under 25 normally makes this a more costly venture.

We made it out of Waterloo by 1pm and made it into Montreal just before 7:30pm, we were lucky with traffic. I had booked the same hotel as last time, and this time I brought my swim suit just in case. As background, Richard the lab tech gave me a hard time that I neglected to tell him that the hotel had a pool before we left. After a yummy meal across the road (Boulevard Taschereau is convenient like that), and taking home a piece of tarte au sucre, I went to sleep quite quickly after a long day.

The next morning we both got up at a good hour, got breakfast, and headed out, not needing to be crazy early for a long setup. We got to the site and started to check the equipment and go a few tests. Being very scientific, I used small rocks to delineate the location of the sensors (since I remembered their location with respect to the trusses from last time).

November 21, 2012 at Daigneault Creek Bridge (rocks on right side to mark location of sensors)

The accelerometers were a prototype design from a subsidiary company of PCB piezotronics, so it was simply a board on a battery pack. There was apparently a casing available, but it did not fit well. The sensors measured acceleration in the long direction of the board and out of plane. Since we were measuring the vertical and lateral accelerations, I picked up little aluminum angles from the UW machine shop to attach to the sides of the battery pack with double-sided tape. Double sided tape was also being used to attach the angles to the top of the bridge girders.

Wireless accelerometer setup. Double sided tape held the aluminum angles to the battery pack and to the bridge

Me with the installation of the wireless sensor on the bridge girder

 Since we only had two accelerometers, but three sets of locations to acquire data (1/4, 1/2 and 3/4 lengths of the bridge), we had to repeat all tests three times over. We ran all the tests that we were capable of replicating (which excluded the crowd, bicycle, and car loading). This time I was the test subject while Ayan stopped and started the data acquisition from his laptop setup from the truck of the rental hatchback (which turned out to be handy).

No cart, no filters, no DAQ, no signal conditioners, just a laptop and a receiver this time around

The last test was really funny to do because Ayan wanted to try a forced loading for a minute by jumping and then wait a minute to measure free vibration, doing this at all 6 sensor locations). After the first few tests though, he cut the jumping time to 30 sec because it was a lot of jumping!

This time around we didn't have any visitors, and Sriram was willing to come down from Ottawa if we had any issues, but everything went smoothly. The only thing we found was that the sensors on occasion would just stop talking to the receiver, which might have been attributed to the cold (around 7ºC). We were done by 1pm, so we hopped back in the car and headed back to Waterloo. We hit a bit of traffic west of Kingston due to construction and got caught in the tail end of commuter Toronto traffic, but overall not too bad.

It was a very brief trip, we didn't get to go to Montreal proper this time around, but I still enjoyed the trip (and got work done). Oh, and as a plus, I got to learn more about Ayan and had some really interesting conversations with him along the way. :)