The HZ®-M Steel Wall System

New standard en 10248 - Part 1: 2023

The development of the HZ®-M Steel Wall System

The demand for deeper berthing facilities due to larger vessels has led to the development of combined walls, integrating primary (king pile) and secondary (intermediary sheet pile) elements. ArcelorMittal pioneered the HZ-ZH system in the 1970s, later enhancing it with HZ/AZ system, widely adopted globally. With the rise of mega ports, ArcelorMittal met the challenge by developing the HZ®-M Steel Wall concept, offering deeper sections with thicker flanges for increased capacity and productivity. This innovative solution, launched in 2008, has since proven its effectiveness in major projects, showcasing the company's commitment to continuous improvement and collaboration across departments.

Launched in 2021, the EcoSheetPile™ Plus label certifies that the steel sheet piles are produced from 100% recycled steel and 100% certified renewable electricity. 

This is covered by an Environmental Product Declaration (EPD), based on dedicated life-cycle analysis. EcoSheetPile™ Plus is an essential part of ArcelorMittal’s XCarb™ recycled and renewably produced initiative to reach carbon neutrality by 2050.

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en English The HZ-M Steel Wall System | EN – 2024.pdf us English (USA) The HZ-M Steel Wall System – 2024 – Imperial.pdf de German Das kombinierte HZ-M – Spundwandsystem.pdf fr French Le nouveau rideau mixte HZ-M/AZ.pdf it Italian Parete combinata HZ-M.pdf es Spanish El sistema de pantalla combinada HZ-M/AZ | SP – 2022.pdf Pt Portuguese O Sistema de Paredes Combinadas HZ-M/AZ | PT – 2022.pdf
The HZM Steel Wall System
Properties per meter of wall
Durability The HZM Steel Wall System
Characteristic values of water pressure
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The HZ®-M Steel Wall System

The HZ-M Steel Wall System is one of the most preferred solutions for port structures and other deep excavations. It is an HZ/AZ combined wall system that comprises the following elements:

  •  HZ-M king pile elements, fulfilling two different structural functions: withstand soil and hydrostatic pressures as well as bear vertical loads;
  • a pair of AZ sheet piles as an intermediary element that has a soil-retaining and load-transferring function and is generally shorter than the HZ-M king piles; 
  • special hot rolled connectors (RH, RZD, RZU) connecting infill sheet piles and HZ-M king piles to guarantee a continuous wall.

Definition of the HZ®-M Steel Wall System

The outstanding feature of the HZ/AZ combined wall system is the extensive collection of possible combinations using the entire AZ sheet pile range (6 solutions for each HZ-M section; AZ range including all rolled-up and rolled-down AZ sections). 

The combinations are based on the same principle: structural supports comprising 1 or 2 HZ-M king pile sections alternating with intermediary double AZ sheet pile sections, or as alternative without any infill sheet piles. 

Durability

For temporary structures, corrosion is usually not a concern, but for permanent ones, it's crucial to assess its impact over the service life. While steel typically withstands atmospheric corrosion well, marine environments pose greater challenges. Analyzing the residual section properties after corrosion in HZ-M Steel Wall Systems requires careful consideration due to higher corrosion levels on the water side. 

ArcelorMittal offers additional protection methods like surface coatings, cathodic protection, and concrete capping beams. They've also developed a corrosion-resistant steel grade, AMLoCor®, available for all HZ-M system elements, with different yield strengths. 

Resistance to water pressure

The HZ-M system demonstrates remarkable resilience to high hydraulic pressures, making it suitable for applications like cofferdam construction in rivers. Extensive testing, including mechanical laboratory tests and finite element simulations, evaluated the system's performance under water pressure. 

Tests conducted at the University of Stuttgart assessed various AZ sheet pile profiles, confirming the system's ability to withstand water head differences of up to 13m for AZ-700 profiles and up to 10m for AZ-800 profiles. The results underscore the reliability of the connectors and interlocks, with no instances of declutching observed during testing.