The test setup equipment was the same as utilized in the first phase. In order to test the specimens under different loading conditions, a New Loading System was developed so that any combination of axial load and lateral force or displacement was possible. In the two last tests, the axial load was a non-proportionally variable load, while the the specimen was displaced monotonically in the lateral direction. The forces (through the home-made load cells) and displacements (through the built-in LDTs) were utilized as the feedback used in the control system and proper commands sent to the actuators to achieve a predetermined force and displacement pattern in the two independent lateral and axial directions. A detailed description of the system developed and used in this testing phase can be found the "Operating Manual" which I prepared for others who may want to employ the system. 

To have an estimate of the behavior of the specimens under different loading patterns (required for a proper programming of the loading system), some pre-test analytical works were necessary. No commercial or educational software was available at the time to address the analytical needs of the case, especially when a non-proportionally variable axial load and a hysteretic lateral displacement was involved. So, I was forced to write my own program, USC_RC, which is a window based application capable of  handling all the analytical needs as described on its page and detailed in its help file.

Besides the aforesaid application, another small application, named USC Viewer, was developed as a tool for examining the response of a system in a two dimensional environment. This application was derived from one of the features already  implemented as a part of USC_RC to view the hysteretic behavior of the material.

Test Results:

Loading conditions for the tests were as follows:

Some of the test results in terms of pictures, curves, and comparison of analytical and experimental results are summarized here.