Pinnacle rock is very jagged and sloped rock, often with no real solid bedrock foundation, the type of rock that is best for caissons.
Pinnacle rock makes caisson drilling and puring much more difficult and costly.
While some pinnacle rock was expected based on original core drillings, the amount of pinnacle rock encountered was not expected. Therefore, before getting too far into caisson work, it was decided to stop the site work temporarily while project engineers further evaluated the subsurface. Now that the site has been mostly excavated, further subsurface evaluation is much easier than it was during the orginally core drillings. Spread footers bascially involve the pouring of a concrete slab as the foundation of the building rather than the pillar type of caissons. Project architects and engineers are currently redesigning the foundation to meet spread footer design requirements.