Reinforced Concrete and Jack Pile Underpinning
JACK PILE UNDERPINNING
This method can be used when the depth of suitable bearing capacity subsoil is too deep to make traditional underpinning uneconomic. Jack pile underpinning is quiet, vibration free and flexible since the pile depth can be adjusted to suit subsoil conditions encountered. The existing foundations must be in a good condition since they will have to span over the heads of the pile caps which are cast onto the jack pile heads after the hydraulic jacks have been removed
NEEDLE AND PILE UNDERPINNING
This method of underpinning can be used where the condition of the existing foundation is unsuitable for traditional or jack pile underpinning techniques. The brickwork above the existing foundation must be in a sound condition since this method relies on the `arching effect' of the brick bonding to transmit the wall loads onto the needles and ultimately to the piles. The piles used with this method are usually small diameter bored piles
Cantilever Beams
This method stabilises existing wall foundations either internally or externally whichever the most appropriate. Two mini-piles are installed, one compression and one tension. A pocket is broken out into the existing wall and a reinforced concrete beam is cast linking the two piles.
This system is used where traditional underpinning is not appropriate due to the existing foundations being deep, or that good-bearing strata is so deep that it is uneconomical to dig. (Depths greater than 1.5m). Or needle beams cannot be used due to access constraints.
Reducing the span between cantilevers can accommodate high loads. However, the bearing capacity of the underlying strata will determine the number, diameter and spacing of piles used.
Advantages of this system are:
Faster than traditional underpinning.
Access from one side only. Occupants can stay in the property during construction.
Economical
This method can be used when the depth of suitable bearing capacity subsoil is too deep to make traditional underpinning uneconomic. Jack pile underpinning is quiet, vibration free and flexible since the pile depth can be adjusted to suit subsoil conditions encountered. The existing foundations must be in a good condition since they will have to span over the heads of the pile caps which are cast onto the jack pile heads after the hydraulic jacks have been removed
NEEDLE AND PILE UNDERPINNING
This method of underpinning can be used where the condition of the existing foundation is unsuitable for traditional or jack pile underpinning techniques. The brickwork above the existing foundation must be in a sound condition since this method relies on the `arching effect' of the brick bonding to transmit the wall loads onto the needles and ultimately to the piles. The piles used with this method are usually small diameter bored piles
Cantilever Beams
This method stabilises existing wall foundations either internally or externally whichever the most appropriate. Two mini-piles are installed, one compression and one tension. A pocket is broken out into the existing wall and a reinforced concrete beam is cast linking the two piles.
This system is used where traditional underpinning is not appropriate due to the existing foundations being deep, or that good-bearing strata is so deep that it is uneconomical to dig. (Depths greater than 1.5m). Or needle beams cannot be used due to access constraints.
Reducing the span between cantilevers can accommodate high loads. However, the bearing capacity of the underlying strata will determine the number, diameter and spacing of piles used.
Advantages of this system are:
Faster than traditional underpinning.
Access from one side only. Occupants can stay in the property during construction.
Economical