When a pile has been driven to refusal It means that?
A rod or pile has been “driven to refusal” when five more blows of an adequate hammer will not budge the rod or pile.
What are three causes of failure of piles?
Flowing strata caused by adjacent excavation or bank sloughing. Tension failure of concrete pile for lack of reinforcement. Eccentricity due to bowing or falling out of plumb. Decay due to lower ground water level.
How the steel pile is driven to the ground?
Prefabricated piles are driven into the ground using a pile driver. Driving piles, as opposed to drilling shafts, is advantageous because the soil displaced by driving the piles compresses the surrounding soil, causing greater friction against the sides of the piles, thus increasing their load-bearing capacity.
How do piles fail?
The main positions of damage are joints between pile head and pile cap or the top of pile. The main failure modes are tension, compression and compression-shear failure. (2) Pile Failure due to excessive bending moment and shear force at the interface between soft and hard soil layer.
Why do piles fail?
1- Inaccurate determination of the bearing capacity of the pile. 2- When the pile load is greater than the design load. 3- Poor and defective workmanship while casting the pile. 4- Corrosion of the timber pile because of assault by insects.
How is pile refusal related to resist Ance?
Pile refusal involves the driving of pi les towards their struct ural limit. The level at which thi s occurs is a function of both the driving resist ance and structural capacity of the pile. (Crapps, 2008).
How to calculate impact of pile driving refusal?
In the case of SPT refusal extrapolate d values were used by directly convert- ing to a 300 mm standard penetration. A total of 403 poi nts fr om 67 impact dr iven prestressed concrete (PSC) pile s across 17 bridge sites were used in the analysis. Piles were general ly 450 to 550 mm octagonal.
How does the toe SPT affect pile refusal?
The influence of the toe SPT increased when piles penetrated rock. A refusal criteri a was established fr om the results to guide both the estimation of bore hole depths and likely pile lengths during the design stage. develop preliminary refusal criteria. concerning the estimation of refusal in rock using the SPT.
How are refusal criteria used in hole design?
A refusal criteri a was established fr om the results to guide both the estimation of bore hole depths and likely pile lengths during the design stage. develop preliminary refusal criteria. concerning the estimation of refusal in rock using the SPT. Pile refusal involves the driving of pi les towards their struct ural limit.