ELEVATION 



(a) Perforated tetrahedron 



ELEVATION 



(c) Tetrapod 



ELEVATION 



(b) Solid tetrahedron 



ELEVATION 



(d) Quadripod 







* k r *\ 





z\ c 



1 





Kr 



1 V 



1 



ELEVATION 



(e) Modified cube 



ELEVATION 



(f) Hexapod 



ELEVATION 



(g) Tribar 



Figure 43. Concrete armor units tested by 

 Jackson (1968a) . 



88 



