Steel Sheet Pile Solutions for Port and Harbor Protection

You are standing at the edge of a busy port. Ships come and go, waves hit the quay wall, and the soil behind the wall wants to slide into the water. The wall must hold for 50 years or more.

Steel sheet piles are the ideal solution for port and harbor protection. They provide a strong, durable, and watertight retaining wall that can withstand wave action, ship berthing loads, and corrosion. Z-type piles (AZ series) are preferred for deep water, while U-type piles are used for moderate depths and curved alignments. Marine grade steel (ASTM A690) is recommended for seawater environments.

I have supplied sheet piles for ports and harbors across the Middle East, Southeast Asia, and Africa. A port in the UAE used AZ 26 piles for an 18-meter deep quay wall. A harbor in Southeast Asia used U-type piles for a curved breakwater. Let me walk you through the steel sheet pile solutions for port and harbor protection.

Sheet pile steel grade

The steel grade for sheet piles in port and harbor protection must provide adequate strength and corrosion resistance¹ for the marine environment.

The most common steel grades for port sheet piles are ASTM A690² (marine grade, 345 MPa yield) for North American projects, and EN 10248 S355GP³ (355 MPa yield) with added alloying elements for European and international projects. For less corrosive environments, ASTM A572 Grade 50⁴ (345 MPa yield) or EN 10248 S270GP (270 MPa yield) may be used.

Steel Grade Selection for Ports

Let me explain the steel grades best suited for port and harbor applications.

ASTM A690² – Marine Grade

• Yield strength: 345 MPa (50 ksi) minimum
• Tensile strength: 485 MPa (70 ksi) minimum
• Chemical composition: Contains copper (0.20-0.50%), nickel (0.20-0.50%), phosphorus (0.07-0.12%)
• Corrosion resistance: 50% better than carbon steel in seawater
• Best for: Ports, harbors, seawalls, marine terminals
• Cost premium: 15-20% over A328

EN 10248 S355GP³ – European High-Strength

• Yield strength: 355 MPa minimum
• Tensile strength: 490-630 MPa
• Corrosion resistance: Standard carbon steel, but can be ordered with added alloying elements
• Best for: Port projects using European standards
• Cost: Moderate

ASTM A572 Grade 50⁴ – High-Strength Low-Alloy

• Yield strength: 345 MPa (50 ksi) minimum
• Tensile strength: 450 MPa (65 ksi) minimum
• Corrosion resistance: Slightly better than A328
• Best for: Deep excavations, heavy loads, freshwater ports
• Cost: Moderate

ASTM A328 – Standard Carbon Steel

• Yield strength: 240 MPa (35 ksi) minimum
• Tensile strength: 410 MPa (60 ksi) minimum
• Corrosion resistance: Standard carbon steel
• Best for: Temporary works, freshwater ports
• Cost: Lowest

Grade Selection Guide for Ports

Environment	Recommended Grade
Seawater, permanent structure	ASTM A6902 or S355GP with marine alloying
Seawater, with cathodic protection	A572 Gr50 or S355GP
Brackish water	A690 or A572 with coating
Freshwater port	A328 or A572
Temporary works	A328

My Experience
For a port project in the UAE (seawater, permanent structure), we used ASTM A690² sheet piles. The marine grade steel provided the corrosion resistance¹ needed for a 50-year design life without cathodic protection.

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Az-700 sheet pile

AZ-700 is a specific section in the ArcelorMittal AZ series of Z-type sheet piles. The number indicates the section width in millimeters.

AZ-700 sheet pile¹ has a width of 700 mm, making it one of the wider Z-type sections. It is used for deep water ports² and heavy-duty retaining walls. The section modulus depends on the thickness, with common variants including AZ 18-700, AZ 26-700, and AZ 34-700. The wide section reduces the number of piles needed per meter of wall.

AZ Series Overview

Let me explain the AZ series and the -700 designation.

AZ Series Naming

• AZ: ArcelorMittal Z-type sheet pile
• Number (18, 26, 34, etc.): Section modulus in 100 cm³/m
• -700: Width in millimeters (optional)

AZ-700 Sections

Section	Width (mm)	Height (mm)	Thickness (mm)	Weight (kg/m)	S (cm³/m)
AZ 18-700	700	340	9.0	73.0	1,800
AZ 26-700	700	390	13.0	106.0	2,600
AZ 34-700	700	440	17.0	140.0	3,400
AZ 42-700	700	480	21.0	173.0	4,200

Advantages of AZ-700 for Ports

• Wide section (700 mm) means fewer piles per meter of wall
• High section modulus for deep water applications
• Ball-and-socket interlock for water tightness
• Available in marine grade steel (ASTM A690 equivalent)

My Experience
For a deep water port project, we used AZ 26-700 piles. The 700 mm width meant we needed only 1.43 piles per meter of wall (compared to 2.5 piles for 400 mm U-type). This reduced installation time by 40%.

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Az steel sheet piles

AZ steel sheet piles¹ are Z-type sections manufactured by ArcelorMittal. They are the standard choice for deep water ports and heavy retaining walls worldwide.

AZ steel sheet piles¹ are hot-rolled Z-type sections with ball-and-socket interlocks². They are available in widths from 630 mm to 700 mm, with section moduli from 1,200 to 5,000 cm³/m. The AZ series is known for high structural efficiency³, excellent driving performance, and good water tightness. They are used for port quay walls, deep excavations, and marine structures.

AZ Series Complete Range

Let me provide the complete AZ series range for port applications.

AZ Series Sections

Section	Width (mm)	Height (mm)	Thick (mm)	Weight (kg/m)	S (cm³/m)	Best Port Depth
AZ 12	630	260	7.0	57.8	1,200	Up to 8 m
AZ 18	670	345	9.0	75.0	1,800	8-10 m
AZ 26	670	396	13.0	109.0	2,600	10-12 m
AZ 34	670	444	17.0	143.0	3,400	12-14 m
AZ 42	670	487	21.0	177.0	4,200	14-16 m
AZ 50	670	529	25.0	211.0	5,000	16-18 m

Key Features for Ports

• High section modulus per kilogram (structural efficiency³)
• Ball-and-socket interlocks for water tightness
• Available in marine grade steel⁴ (ASTM A690 equivalent)
• Wide sections reduce number of piles
• Proven performance in ports worldwide

AZ vs PU (U-type) for Ports

Feature	AZ (Z-type)	PU (U-type)
Structural efficiency	Higher	Good
Width	630-700 mm	400-600 mm
Best depth	Deep water (10-18 m)	Moderate (up to 10 m)
Curved walls	Difficult	Excellent
Water tightness	Good	Good

My Experience
For a major port expansion in the Middle East, we used AZ 26 piles for the main quay wall. The piles were 18 m long (exposed) plus 11 m embedment, total 29 m. The AZ series provided the strength needed for the deep water application.

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U type hot rolled steel sheet piles¹

U type hot rolled steel sheet piles¹ are the traditional choice for port and harbor protection. They are symmetric and easier to install in curved alignments.

U type hot rolled steel sheet piles¹ have a symmetric U-shaped profile with Larssen ball-and-socket interlocks². They are available in widths of 400 mm and 600 mm, with heights from 100 mm to 210 mm. U type piles are ideal for moderate water depths (up to 10 m) and curved harbor alignments³. They offer excellent water tightness and are available in marine grade steel⁴.

U Type Series for Ports

Let me provide the U type series range for port applications.

U 400 Series

Section	Width (mm)	Height (mm)	Thick (mm)	Weight (kg/m)	S (cm³/m)	Best Port Depth
U 400 x 100	400	100	10.5	48.0	1,080	Up to 5 m
U 400 x 125	400	125	13.0	60.0	1,590	5-7 m
U 400 x 170	400	170	15.5	76.1	2,470	7-9 m

U 600 Series

Section	Width (mm)	Height (mm)	Thick (mm)	Weight (kg/m)	S (cm³/m)	Best Port Depth
U 600 x 130	600	130	10.3	61.8	2,350	Up to 7 m
U 600 x 180	600	180	13.4	81.6	3,820	7-9 m
U 600 x 210	600	210	18.0	106.2	5,730	9-10 m

Key Features for Ports

• Symmetric shape for easy installation in curved alignments
• Larssen ball-and-socket interlocks² for water tightness
• Available in marine grade steel⁴ (ASTM A690)
• Proven track record in ports for over 100 years

When to Use U Type for Ports

• Curved harbor alignments (breakwaters, marina berths)
• Moderate water depths (up to 10 m)
• Projects where installation simplicity is important
• Smaller ports and marinas

My Experience
For a marina project in Southeast Asia with curved berths, we used U 400 x 125 piles. The U-type piles followed the curve easily, and the installation was straightforward. The wall has performed well for over a decade.

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Conclusion

Steel sheet pile solutions for port and harbor protection include AZ series (Z-type) for deep water¹ and U-type for moderate depths. Use marine grade steel (ASTM A690 or S355GP with alloying)² for seawater environments. AZ-700 offers wide sections for efficient installation. U-type piles are ideal for curved alignments.

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