Some explanation from Prof. Pessiki while the test is in the initial load.
The spiral column being tested.
This is one big mean testing rig!
The typical column at failure. Notice the failure is pointed one specified area?
Closer view. Notice the 'bend' reinforcement. This is due to the load which eventually leads to the concrete spalling hence structural failure.
The upper part of the specimen.
Embedded strain gauges were used to capture the strain readings on the reinforcements.
At failure. Notice that the spalling of the concrete is more comprehensive and throughout the middle section of the column? The actual failure is due to the spiral reinforcement in tension. The failure is gradual.
Notice the spiral reinforcement that 'holds' the column, breaks. If we draw a line crossing the column connection the break points of the spiral reinforcement, it resembles a shear failure.
The spiral reinforcement at closer view.
When asked about the total cost for the tests, Prof. Pessiki told me that it was about US$30,000. But again, it was paid by the students money who registered for the course. So, don't complain too much when you have to pay some fee when you register for your postgraduate degree. You will get back the benefit.