Installation Process

Diesel Impact

    Piles shall be be driven with a drop, an air, a diesel a hydraulic hammer conforming to these specifications.

    Pile driving hammers shall be of the size needed to develop the energy required to drive the piles at a blow count that does not exceed 10 blows per inch (25 mm) at the required ultimate pile capacity. 

Other

Helical pile

Hydraulic

Vibratory

Internal Impact

Auger Cast

Large Diameter Pipe Pile

Shoring

Leads

    Pile driving leads that align the pile and the hammer in proper positions throughout the driving operation shall be used.  Leads shall be constructed in a manner that affords freedom of movement of the hammer while maintaining alignment of the hammer and the pile to ensure concentric impact for each blow. 

    The leads shall be so designed as to permit proper alignment of battered piles when applicable.

   Leads may be either fixed or swinging type.  Swinging leads, when used, shall be fitted with a pile gate at the bottom of the leads.  The leads shall be adequately embedded in the ground or the pile constrained in a structural frame such as a template to maintain alignment.  

Driving

    Unless approved by the Engineer, piles shall be driven to

• the required ultimate pile capacity, or
• the required ultimate pile capacity and minimum tip elevation, if specified, or
• the specified tip elevation

    The ultimate pile capacity is usually confirmed by achieving the specified blow count which is the number of hammer blows required to cause one foot (300 mm) or one inch (25 mm) of penetration.  The blow count shall always be measured, either during initial driving or by re-driving with a warm hammer after a wait period, as determined by the Engineer.

    For diesel hammers the stroke shall be recorded.  Either energy or impact velocity shall be recorded for hydraulic hammers.

    If water jets are used in connection with the driving, the ultimate pile capacity shall be determined from the results of driving after the jets have been withdrawn.

    The procedure used in driving the piles shall not subject them to excessive and undue abuse producing crushing and spalling of the concrete, injurious splitting, splintering and brooming of the wood, or excessive deformation of the steel.   

Accuracy of Driving

    Piles shall be driven with a variation of not more than ¼ inch per foot (1:50) from the vertical or not more than 1/2 inch per foot (1:25) from the batter shown in the contract documents.

     After driving, the pile head shall be within 6 inches (150 mm) of plan locations for all piles capped below final grade.

    No pile shall be nearer than 4 inches (100 mm) from any edge of the cap.   Any increase in pile cap dimensions or reinforcing caused by out-of-position piles shall be at the Contractor's expense.