Basis of Design Book 2 - City of St. Petersburg

Memorandum
March 1, 2010
Page 4 of 6
Legend:
Limited Access Area*
Open Pier Area
Figure: Pier Demolition/Construction Scenarios
*The area shown as Limited Access is only valid when the ‘inverted pyramid’ building is to remain in
place. If the ‘inverted pyramid’ building is removed, the entire pier is considered open.
Demolition Costs:
Demolition for the open pier condition was developed by calculating quantities based on the existing
pier drawings. The cost estimate considers demolition of concrete beams, deck and piles. Costs were
based on cubic yards of concrete removed and disposed of locally.
If the City decides to keep the existing ‘inverted pyramid’ building, then selective demolition will be
required to remove the 1920s deck and beams in a limited access condition. As previously mentioned,
limited access construction will be less efficient and more expensive. The unit costs developed assume
all interior building demolition required to access the deck has been completed. As cranes will have
limited ability in this area, demolition of the deck and beams will have to be completed with less
efficient equipment. The costs to demolish, remove and locally dispose of the concrete beams, piles
and deck have been included. Typically, new piles would be driven to support a new deck and beams;
however, piles cannot be driven in this area because of the limited mobility of cranes and lack of
overhead clearance for driving. For this reason, the existing piles will remain and must be repaired for
reuse if the existing ‘inverted pyramid’ building is kept. Therefore, the limited access cost estimate
assumes that no piles under the ‘inverted pyramid’ building are removed.
If the City decides to replace the building, the approach to removal of the building foundations
assumed the following steps per foundation:
1. Cutting of the steel sheet pile vertically in two locations in each caisson face
2. Drilling five holes in the concrete to allow saw cutting of an expansion release
3. Drilling a pattern of holes for the insertion of expansive grout to crack the mass concrete
4. Excavation of the concrete from within the caisson
5. Extraction of the steel sheet and main load-bearing piles
6. Disposal of all materials