King Pile Types and Configuration in Combi Wall System

What Is a King Pile Wall?

King piles and intermediate piles are the 2 main pile members in the king pile combi-wall system. It utilizes pipe piles, H piles, and welded box piles to meet the strength and stability requirements of heavy-duty water and earth-retaining projects.

• King pile is the primary bearing pile in various combined wall systems; the main forms include large-diameter pipe pile, H-section pile, and box pile. They connect to the intermediate sheet piles to form the earth-retaining structure.
• Intermediate sheet piles are the pile members between king piles, such as Larsen sheet piles (U, Z, and flat-type sheet piles), which are designed with interlocks to connect the king piles.

Note: Although pipe piles are the most widely used king piles, H-piles, box piles, double pipe piles, and concrete piles can also serve as primary load-bearing members in combi wall systems. The selection depends on structural requirements, soil conditions, and project economics.

Why Use King Piles in Combi Walls?

King piles are made into large-section, high-rigidity structural steel sections; they are the strongest pile members driven into the greatest embedded depth. Using king piles can provide the following advantages:

• Higher bending resistance
• Reduced steel consumption
• Capability for deep excavations and waterfront structures
• Flexible combinations with different sheet piles
• Suitability for marine and heavy-duty applications

King Pile Wall Types Introduction – Combi Wall Systems

Pipe piles, H piles and box piles are all suitable pile members can be used as king piles. Here are the 3 most commonly used combi wall systems: pipe king pile wall, H pile king pile wall and box pile king pile wall.

Pipe King Pile Combi Wall

Introduction: The pipe king pile combi wall structure has excellent stiffness; it is formed by large-diameter steel pipe piles interlocked with metal sheet piles. It is the most frequently used king pile wall form in deep-water retaining projects, such as quay walls, container terminals, cofferdams, and offshore structures.

Steel pipe piles used as king piles are generally made of Q345 or higher grade steel, with diameters ranging from 400 mm to 1200 mm and wall thicknesses controlled between 10 mm and 25 mm to accommodate different load requirements. The manufacturing process involves hot rolling or cold bending to ensure a smooth surface and dimensional accuracy.

H-Pile King Pile Systems

Introduction: An H-pile king pile wall structure is simply formed by H-piles and intermediate sheet piles; it is an economical king pile wall system featured with lightweight and easy installation. It is used mostly in temporary retaining wall projects of bridge foundations and deep excavations. AGICO supplies HZZ combi wall solutions, which is equivalent to the HZM combi wall system.

The HZZ beam has a unique structure with a drop-down nose and Larsen lock, formed directly on the flange of a hot-rolled H-beam, enabling direct interlocking of sheet piles and main piles. It is made in the hot-rolled process, and allows for an unlimited number of combinations of section height, web thickness, and flange dimensions.

Box Pile King Pile Systems

Introduction: The box pile king pile adopts steel box pile as the king pile and hot-rolled sheet piles as the intermediate pile; the steel box pile is produced by welding Larssen-type U or Z sheet piles. It is a heavy-duty king pile with a large section modulus and high bending capacity. The box pile king pile wall is suitable for deep harbor pile structures and large quay walls.

Steel box piles are a type of welded pile with 2 U-type sheet piles or 4 Z-type sheet piles or can be produced with 2 Z pile and 1 U shaped section steel sheet. A steel plate is usually welded in the box pile center to improve its strength. After the box pile section is formed, it offers a larger section modulus and improved bending capacity. Box pile combi wall is an excellent choice for a heavy-duty piling project.

Comparison of Common King Pile Types

Compared with steel sheet pile walls, the king pile combi-walls show the advantages of different levels of excellent section modulus and strength. Here is a comparison table of different kinds of king pile walls, including features and applications for reference.

Typical Applications of King Pile Combi Walls

• Port and Harbor Structures
• Quay Walls and Bulkheads
• Cofferdams
• Deep Excavations and Dry Docks
• Flood Protection Systems
• Seawalls and Breakwaters
• Lock Chambers and Navigation Structures
• Bridge Abutments and Riverbank Protection
• Industrial Waterfront Facilities