Alternative Support Systems for Cantilever - National Transportation ...

The basis for the selection of the concrete shaft’s diameter was one half of the diameter of
a typical field design. One problem that also needed to be addressed was to maintain the
torsional strength of the concrete shaft below that of the previously fabricated lever arm
assembly. Based on the quantified strength of the embedded pipe and plate assembly, the
remaining components of the test apparatus were designed to preclude all failure modes other
than the concrete breakout or side-face blowout of the welded torsional plates and/or flexural
plate.
More detailed information regarding the design of the components of the test apparatus is
provided in the subsequent sections. Much of the design of the embedded pipe and plate
apparatus and reinforced concrete shaft was performed using an iterative process. Therefore, the
following sections will be organized as chronologically as possible, though some information in
later sections was necessary to design components in earlier sections. Figure 4-4, Figure 4-5,
Figure 4-6, and Figure 4-7 provide more detailed drawings of the torsion test apparatus. The
flexural test apparatus was very similar with the main differences being an inclusion of a flexural
plate on the embedded section and a flexural extension pipe on the testing assembly. Figure 4-8
shows a 3-D isometric view of the embedded section for the second test. For larger scale,
dimensioned drawings for both tests, refer to Appendix A. Complete design calculations are
located in Appendix B.
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