ASTM A252 Steel Pipe Piles
ASTM A252 specification covers nominal (average) wall steel pipe piles of cylindrical shape and applies to pipe piles in which the steel cylinder acts as a permanent load-carrying member, or as a shell to form cast-in-place concrete piles. Pipepiles are produced as both welded and seamless products.
ASTM A252 steel pipe piles are classified into three grades based on their yield strength and tensile strength: Gr.1, Gr.2, and Gr.3.
ASTM A252 Gr. 2 is the most common general-purpose choice, with Gr. 1 for lighter duty and Gr. 3 for the most heavy-duty and challenging applications.
ASTM A252 steel pipe piles shall be made by the seamless, electric resistance welded, flash welded, or fusion welded process. The seams of welded pipe piles shall be longitudinal, helical-butt,or helical-lap.
Chemical Requirements Of ASTM A252 Steel Pipe Piles
The chemical analysis is quite important when ordering ASTM A252 steel pipes. The chemical analysis shall be performed by test methods, practices, and terminology ASTM A751. It shall be permissible for the buyer to make product analyses using 2 samples from each heat lot of pipe piles. The chemical composition thus determined shall conform to the requirement specified for phosphorus. The steel shall contain no more than 0.050% phosphorous.
Tensile Requirements Of ASTM A252 Steel Pipe Piles
ASTM A252 pipes must meet the tensile performance requirements listed in the table below.The yield point shall be determined by the drop of the beam, by the halt in the gage of the testing machine, by the use of dividers, or by other approved methods. When a definite yield point is not exhibited, the yield strength corresponding to a permanent offset of 0.2 % of the gage length of the specimen, or to a total extension of 0.5 % of the gage length under load shall be determined
TABLE 1 Tensile Requirements
NOTE 1-Where an ellipsis (...) appears in this table, there is no requirement.
| Grade 1 | Grade 2 | Grade 3 | ||
| Tensile strength, min, psi [MPa] | 50 000 [345] | 60 000 [415] | 66 000 [455] | |
| Yield point or yield strength, min, psi[MPa] | 30 000 [205] | 35 000 [240] | 45 000 [310] | |
| Basic minimum elongation for nominal wall thicknesses 5/6 in. [7.9 mm] or more: | ||||
| Elongation in 8 in. [203.2 mm], min, % | 18 | 14 | ... | |
| Elongation in 2 in. [50.8 mm], min, % | 30 | 25 | 20 | |
| For nominal wall thicknesses less than 5/16 in. [7.9 mm], the deduction from the basic minimum elongation in 2 in. [50.8 mm] for each 1/32 - in. [0.8 mm] decrease in nominal wall thickness below 5/16 in. [7.9 mm], in percentage points | 1.50A | 1.25A | 1.0A | |
| A Table 2 gives the computed minimum values: | ||||
| TABLE 2 Calculated Minimum Elongation ValuesA | ||||
| Nominal Wall Thickness | Elongation in 2 in.[50.8 mm],min,% | |||
| in. | [mm] | Grade 1 | Grade 2 | Grade 3 |
| 5/16 or 0.312 | [7.9] | 30 | 25 | 20 |
| 9/32 or 0.281 | [7.1] | 28.5 | 23.75 | 19 |
| 1/4 or 0.250 | [6.4] | 27 | 22.5 | 18 |
| 7/32 or 0.219 | [5.6] | 25.5 | 21.25 | 17 |
| 3/16 or 0.188 | [4.8] | 24 | 20 | 16 |
| 11/64 or 0.172 | [4.4] | 23.25 | 19.5 | 15.5 |
| 5/32 or 0.156 | [4.0] | 22.5 | 18.75 | 15 |
| 9/64 or 0.141 | [3.6] | 21.75 | 18.25 | 14.5 |
| 1/8 or 0.125 | [3.2] | 21 | 17.5 | 14 |
| 7/64 or 0.109 | [2.8] | 20.25 | 16.75 | 13.5 |
| A The above table gives the calculated minimum elongaion values for vanious nominal wall thickmesses.Where the specified nominal wall thickness is intermediate to those shown above, the minimum elongation value shall be determined as follows: Grade 1 E=48t+ 15.00 [E=1.90t+ 15.00] 2 E=40t+ 12.50 [E=1.56t+ 12.50] 3 E=32t+ 10.00 [E= 1.25t+ 10.00] where: E = elongation in 2 in.,%,and t = specified nominal wall thickness,in.[mm]. |
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Permissible Variations Of Astm A252 Steel Pipe Piles
- Weight-When specified on the purchase order, each length of pipe pile shall be weighed separately and its weight shall not vary more than 15% over or 5% under the theoretical weight,calculated using its length and its weight per unit length (as follows)
The weight per unit length shall be calculated as follows:
W = 10.69(D - t)t
[W = .0246615 (D - t)t]
where:
W = weight per unit length, lb/ft [kg/m],
D = specified outside diameter, in. [mm], and
t = specified nominal wall thickness, in. [mm].
- Outside Diameter-The outside diameter of pipe piles shall not vary more than 61 % from the specified outside diameter.
- Wall Thickness-The wall thickness at any point shall not be more than 12.5 % under the specified nominal wall thickness. The following calculation shall be used to determine the minimum wall thickness:
t n × 0.875 = tm
where:
tn = nominal wall thickness, and
t m = minimum permissible wall thickness.
The wall thickness is expressed to three decimal places, with rounding being in accordance with Practice E29.
Key Characteristics Of ASTM A252 Steel Pipe Piles
The key characteristics of ASTM A252 steel pipe are defined by its purpose as a structural foundation piling pipe. Unlike pipes designed for fluid transport (e.g., API 5L), A252 prioritizes strength and durability to withstand driving forces and permanent load-bearing in the ground.
- Purpose-Built: Designed explicitly to be driven into the ground as structural foundation piles.
- High Strength Grades: Available in three grades with progressively higher yield and tensile strengths (Grade 1, 2, 3).
- Dimensional Variety: Comes in a vast range of large diameters and wall thicknesses to meet specific engineering loads.
- Weldability Focus: Chemical composition is controlled to ensure good weldability for splicing sections.
- Tested for Integrity: Must pass flattening tests (for welds) and tensile tests to ensure it can withstand the forces of driving and long-term load-bearing.
Application of ASTM A252 Steel Pipe Piles
ASTM A252 piling pipes are cylindrical steel pipes specifically engineered for foundation support and load-bearing applications in construction, infrastructure, and industrial projects. They serve as either permanent structural members or shells for cast-in-place concrete piles, offering high strength, durability, and adaptability to diverse soil and environmental conditions.
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