In the construction of pile foundations, concrete square piles and pipe piles are involved, and these two types of piles are different from each other in terms of appearance and characteristics.

The difference between pipe piles and concrete square piles:

1) Different bearing capacity

Concrete square pile bearing capacity is slightly larger than that of pipe pile, its pile itself bearing capacity is equivalent to 500 OD thick-walled pipe pile; the cost per KN bearing capacity is lower than that of prestressed pipe pile, which means that the designer can prefer square pile under the same design bearing capacity. Both types of piles are the foundation structure of the building and can be used to bear the pressure of the superstructure.

2) Different shear resistance

The theoretical calculated shear resistance of square pile is 2-3 times of the equivalent pipe pile, and according to the experimental test, it can even reach 4.5 times of the pipe pile, that is, the seismic performance of hollow square pile is very superior, suitable for promoting the use of foundation in areas with many earthquakes and high-rise buildings, large basement buildings, etc.

3) Different impact resistance performance

The square pile inherits and carries forward the characteristics of low breakage rate of the original concrete square pile construction. The high-strength concrete with square head has better impact resistance and much smaller breakage rate than the pipe pile; the square has larger welding perimeter than the round, which fully guarantees the effective welding strength between each section of the pile and greatly reduces the phenomenon of joint de-welding or displacement in the construction of the square pile, making its quality better.

Classification of pipe piles:

1) Pipe piles are classified into prestressed concrete pipe piles (PC pipe piles), prestressed concrete thin-walled pipe piles (PTC pipe piles) and prestressed high-strength concrete pipe piles (PHC pipe piles) according to concrete strength grade and wall thickness. concrete strength of PC piles shall not be lower than C50 concrete, strength grade of PTC pipe piles shall not be lower than C60 and concrete strength grade of PHC piles shall not be lower than C80.

PC piles and PTC piles are generally maintained by atmospheric pressure steam, and generally take 28 days to be applied. As for PHC piles, after demoulding, they should be steam cured in autoclave, and the concrete strength grade up to C80 will only take three or four days after steam curing at 10 atmospheres and 180 degrees.

2) Square piles are divided into prestressed concrete, prestressed high-strength concrete square piles codenamed PC and prestressed high-strength concrete square piles codenamed PHS according to the concrete strength grade and wall thickness. The concrete strength of PS piles shall not be lower than C60 concrete and the concrete strength grade of PHC piles shall not be lower than C80.

The shape of square piles is easier to develop non-welded quick connectors, which can truly be constructed all-weather and faster, and can avoid the cracking of welded pile heads in high groundwater level.