Alternative Support Systems for Cantilever - National Transportation ...

Rear of shaft
Figure 5-14. Load and torsional rotation for test specimen for the second test
5.2.3 Summary of Torsion and Flexure Test
Face of shaft
Overall, this test proved the embedded pipe and plates section was successful at
transferring load from the superstructure to the substructure. It was determined that the modified
anchor breakout equations for flexure also accurately predicted the behavior and strength of the
failure (See Equations 3-11, 3-12, and 3-13). The predicted failure load for the concrete breakout
in flexure was 26.4 kips (See Table 4-2) and the applied failure load was 26.3 kips, with the
largest breakout occurring on the bottom of the test specimen, indicating a flexure failure. The
test specimen had a breakout failure deep within the foundation at the approximate location of
the flexural plate. It was also determined that the alternative tested had approximately twice the
strength of the calculated strength of an equivalent 12 anchor bolt system. For more details on
the calculated strength of an equivalent anchor bolt system compared to the test apparatus’
strength, see the test apparatus calculations in Appendix B.
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Base plate