Special Requirements for Mat Foundations.

a. Control of groundwater.   Exclude groundwater from the excavation by means of cutoffs, and provide for temporary or permanent pressure relief and dewatering by deep wells or wellpoints as described in TM 5-818-5/AFM 88-5.  Specify piezometers to measure drawdown levels during construction.  Specify the pumping capacity to achieve required drawdown during various stages of construction, including removal of the temporary system at the completion of construction.  Consider effects of drawdown on adjoining structures.

b. Downdrag.   Placement of backfill against basement walls or deep raft foundations constructed in open excavations results in downdrag forces if weight of backfill is significant with respect to structural loading.

0 comentarios:

Post a Comment