Testing and Requirements

The balsa wood bridge will be tested on a number of requirements, such as a block traversing through the road deck, the articulation system being able to raise the road deck 280 mm above the original position, the bridge able to rest on the 60 mm wide abutments, a 10 gram weight added to be able to raise the bridge enough to slide a sheet of paper between the abutment and the bridge, the bridge able to support a load between 18.9 kg to 20 kg, and finally the opening spanning at least 400 mm. For some of these requirements, a measuring device such as a tape measure or a ruler can be used. For loads, they can be measured for their weight prior to adding it on the bridge. The weight of the bridge can also be measured with a scale. The last set of requirements can simply be checked off as a pass or no pass. The deliverables that would be needed for the testing would include a data sheet covering al the requirements, and videos demonstrating the requirements being tested.

Testing Deliverables

The deliverables that would be required for this project are the data sheet that covers all the requirements, and the videos demonstrating the requirements being tested. The requirements on the data sheet would likely have whether the bridge was able to meet the said requirements. For each of these requirements, video recordings would be needed to demonstrate the bridge’s performance during testing whether the bridge succeeded or failed at these requirements. Pictures may also be taken during testing as well to support the testing videos.

Testing Preface

Fundamentally, for all the tests with the exception of the weight test, the bridge was placed on top of steel abutments. Prior to the testing done, the bridge's opening span was measured and had at least a 400 mm opening between the abutments. Per the requirements in the criteria of the project, the bridge was able to meet the requirements for resting on the steel abutments in addition to those for the opening span.

Weight Testing

The predicted result for the weight testing of the bridge was that it would weigh less than 85 grams, in which the actual weight of the bridge was much less than 85 grams weighing at about 47.81 grams. There wasn’t much of an issue involved with this test, all it required was putting the bridge onto a digital scale and reading the result.

Vehicle Traversal Testing

For the second test, the goal here is to be able to get the vehicle (represented by a block) from one end of the bridge to the other without any issues. The vehicle will be pulled across the bridge by using a string. An issue that came up during this test was that the vehicle hit the center hole of the road deck while it was being pulled across. This was rectified by smoothing out the center hole of the road deck so that it wouldn't be as much of an issue. Take into account that the center hole is slightly larger than the 6 mm diameter as specified, sitting closer to sightly over 9 mm since imperial drill bits were used. Not much else could be solved about this issue beyond possibly making a new road deck.

Vertical Articulation Testing

In the third test, the goal for vertical articulation is to be able to raise the road deck at least 280 mm above its original position on the bridge. This will be accomplished by placing the articulation system on top of the bridge and looping the string around the road deck.

Testing for Bridge Raising

In this fourth test, the goal for bridge raising is to use the articulation system to raise the bridge for at least 10 seconds with the addition of 10 grams to the lifting component. Also during that time a sheet of paper can slide between the abutment and the raised bridge. An optional addition to this test is the time that the bridge took to be raised will also be tested.

Load Testing

In the last test, the goal for the bridge is to be able to hold a load of 20 kg bearing on the center of the bridge through the hole in the road deck. A rod would be inserted and have an attached loop to connect the bucket to via bungee cords. The bucket will be suspended in the air for the bridge to feel the full load of a water-filled bucket.