4. let's have a closer look at volcanic ash
However, the option of solid abutments on specific perimetral points is structurally not selfreferential as it transfers an oblique force to the surrounding ground (diagram bottom). The thrust is not reacted only by the mass of the abutment but also by the mass of soil surrounding it.
oblique resulting vector
m
load
solid concrete abutment 2m x 3m
0m
thrust
40
If we reconsider this detail we might encounter failures due to the often poor and unconsolidated surface soil consistency in many parts of Quito. Therefore it was decided that tieing the abutments back to each other (diagram opposite page, bottom) and post-tensioning the tie would be a safer option in the light of unpredictable ground conditions. Thus the load transferred to the ground is essentially vertical.
profile of shell varies in thickness (more information in 5.8) 200mm
250m m
30 0m m
35 0m m ties
1:100 section
thrust
vertical compression
tension tie
GAUSSIAN
In red, areas of anticlastic curvature affected by double thrust along intersection of 2 domes.
6. emptying it out