SY390 U-type steel sheet pile is a U-shaped sheet pile rolled to the SY390 steel grade of JIS A 5528. It is a hot-rolled section with a symmetrical open U-shaped cross-section; a formed interlock extends the full length along each of its two vertical edges, and when one pile is set beside the adjacent pile the interlocks engage - once the whole row is driven, it forms a continuous watertight earth-retaining wall.
Chemical Composition of the SY390 U-Type Sheet Piles
The SY390 grade is produced with a controlled chemical composition that maintains weldability while ensuring yield strength. The typical limits for hot-rolled U-type supply are as follows, subject to the applicable execution standard:
| Element | C | Si | Mn | P | S | Cu | Ni | Cr | Mo |
|---|---|---|---|---|---|---|---|---|---|
| Max. content (wt%) | 0.22 | 0.55 | 1.60 | 0.040 | 0.040 | 0.35 | 0.30 | 0.30 | 0.10 |
Note:representative chemistry limits for orientation; the full composition of the supplied heat is stated on the mill certificate.
Mechanical Properties of the SY390 U-Type Sheet Piles
| Property | Value (per JIS A 5528) | Meaning in service |
|---|---|---|
| Guaranteed min. yield strength | 390 MPa min. | Stress the pile can carry before yielding; sets wall capacity |
| Tensile strength | 490 MPa min. (typ. 540 MPa) | Headroom before rupture; matches the higher yield |
| Elongation (test piece No. 1A) | 16% min. (typ. 15–17%) | Ductility to survive interlock driving and handling |
Note:values per JIS A 5528:2021. Confirm the exact mechanical results, test-piece type, and grade against the mill certificate for the section supplied.
Sections Supplied for SY390 U-Type Piles
SY390 U-type piles are supplied in a range of sizes defined by width, depth, plate thickness, and pile length. A representative U-section is about 400 to 600 mm wide and 100 to 215 mm deep; the deeper the section, the higher its section modulus, so it can carry taller, more heavily loaded wall faces. Pile lengths are extended by splicing within the wall to achieve longer runs.
| Section | Width (mm) | Depth (mm) | Thickness (mm) | Section modulus (cm³/m) |
|---|---|---|---|---|
| 400-wide, shallow (e.g. PU 400×100) | 400 | 100 | 10.5 | 874 |
| 400-wide, deep (e.g. PU 400×125) | 400 | 125 | 11.0 | 1,042 |
| 500-wide (e.g. EU/PU 500×125) | 500 | 125 | 12.0 | 1,140 |
| 500-wide, deep (e.g. PU 500×150) | 500 | 150 | 12.5 | 1,445 |
| 600-wide (e.g. GU 600×130) | 600 | 130 | 13.5 | 1,610 |
| 600-wide, deep (e.g. PU 600×215) | 600 | 215 | 14.0 | 2,960 |
Why Choose the SY390 Grade?
Selecting SY390 over a standard grade lets the same-size section carry greater load, or a lighter section carry an equivalent load.
| JIS A 5528 grade | Min. yield strength (MPa) | Typical role |
|---|---|---|
| SY295 | 295 | Ordinary retaining and water walls |
| SY390 | 390 | Deeper, heavier or deformation-sensitive walls |
| SY400 | 400 | The same higher-duty role, marginally stronger |
Advantages of SY390 U-Type Piles
Watertight Interlocks. The formed interlocks close each pile into the adjacent one, retaining both water and soil.
Favorable Stiffness-to-Weight Ratio. The open U-shaped section delivers a high section modulus, letting a slender driven sheet line support heavily loaded walls.
Enhanced Load Capacity from the Grade. SY390 steel raises the depth and load a given section can carry relative to a standard-strength grade.
Fast, Recoverable Installation. The piles can be installed quickly by vibratory, impact, or static-press methods and extracted for reuse on temporary works.
Applications of SY390 U-Type Steel Sheet Piles
Because it combines a higher-strength grade with a well-proven watertight interlock, the SY390 U-type pile is used where the wall must carry loads beyond what a standard-strength section can bear while staying watertight:
Deeper retaining walls - carrying larger retained heights and surcharge.
Water-retaining and flood-control walls - where both a higher grade and watertight interlocks are required.
Quay and waterside walls - carrying berthing and ground loads.
Excavation pits and cofferdams - supporting the excavation without excessive deformation.
Protection works - such as pier protection against scour and impact.
How to Order SY390 U-Type Steel Sheet Piles?
To order SY390 U-type steel sheet piles, establish the section, grade, and execution standard as the basis of the order, and verify the supply against the mill certificate. The information to be confirmed for an order is shown in the table below.
| Order requirement | What it specifies | Governing item to confirm |
|---|---|---|
| Section | Width, depth, and thickness of the U-section | Section modulus against the required bending moment |
| Length | Individual pile length; spliced where a longer run is needed | Length and cumulative length to delivery |
| Grade | SY390 of JIS A 5528, or equivalent under GB/T 20933 / EN 10248 | Grade named in the mill certificate |
| Governing standard | The standard the section and grade are furnished to | Standard stated in the mill certificate |
| Quantity and delivery | Total quantity and destination | Quantity and dispatch to the agreed destination |
| Finishing | Any coating the medium and service require | Coating or interlock finish agreed with supply |
Note:the mill certificate states the section, the grade, the mechanical results (yield, tensile, elongation) and the standard.
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FAQ:
What exactly is an SY390 U-type steel sheet pile?
It is a U-section sheet pile rolled to the SY390 grade of JIS A 5528 - the U-section is the shape, and the SY390 the steel with a guaranteed yield of 390 MPa. Together they define this one pile.
What does SY390 mean?
SY390 is a JIS A 5528 grade: S for steel, Y for yield, 390 for a guaranteed minimum yield strength of 390 MPa.
What sections is the SY390 U-pile available in?
Representative U-sections span about 400 to 600 mm in width and 100 to 215 mm in depth, from a shallow 400-wide to a deep 600-wide section carrying the highest section modulus.
Why choose SY390 over a normal grade?
Because it carries a wall at a larger load or a smaller deformation: a deeper or heavier wall holds to an acceptable deformation, or a lighter section carries the same load.
What must a quotation confirm?
Confirm the section (width, depth, thickness, length), the grade SY390 or its equivalent, the governing standard, quantity, destination, and verify the mechanical results against the mill certificate.