Sheet piles are sections of sheet metal with interlocking edges that are driven into the ground to provide earth retention and excavation support. Sheet piles are usually made of steel, but can also be made of timber or reinforced concrete.
Sheet piles are commonly used for retaining walls, land reclamation, underground structures such as car parks and basements, marine locations for riverbank protection, seawalls, cofferdams etc.
The choice of steel sheet piles depends on factors such as
For example, the type of work. Whether permanent or temporary.
Site conditions.
The required pile depth.
The bending moment involved.
The nature of the structure.
The type of protection required.
Timber sheet piles
Z Type Sheet Piles
The Z-shaped pile follows Larssen's wave profile concept, but has the additional advantage of interlocking on the outer elements of the section. The extra metal is fully utilised as it is located away from the neutral axis of the wall. The Larssen interlocking device is located on the neutral axis. Surprisingly, Z-piles were being produced in Europe as early as 1911. the Ransome profile looks very much like some of today's lighter Z-piles. the deeper Lamp Z-pile introduced around 1913 resembled the modern ball-and-socket Z-pile.
In Europe, the Z-shape fell out of favour with the development of the Larsen U-shape. two Z-shapes were introduced in the USA in the 1930s and became popular. the PZ-38 and PZ-32 offered wider and deeper sections than any arch shape available at the time. the Z-shape pile gained some impetus in the USA from the long-running debate about the actual flexural performance of U-shapes and arch sections.
The Z-pile interlocks at the end of the wall and provides a strong web connecting the two flanges. When the PZ-27 section was introduced in the 1940s, its section modulus of 30.2 in 3 /ft was almost three times that published for an arched section of the same weight per square foot of wall. This section subsequently became the most popular sheet pile section in history. Z-shapes are now produced with section moduli ranging from 8.6 to approximately 85 in 3 /foot of wall.
Z-shaped piles are mainly used in retaining wall and flood wall applications where bending strength dictates the design and no deflection (oscillation) is required between the sheets. Most manufacturers do not guarantee any oscillation, although some oscillation can usually be achieved, or areas can be constructed by providing some bent pieces in operation. It is possible to use standard bending angles or prefabricated angles to turn in wall alignment.
Z-piles are not used in applications where interlocking strength is required, for example to fill batteries. In these cases, these sheets tend to stretch and flatten. For this reason, no minimum interlocking strength is provided. When interlocking tension is a major design consideration, arch or straight web piles should be used.
U Type Sheet Pile
It is available in various cross-sections and shapes. They can be hot-rolled sheet piles, cold-rolled sheet piles or cold-formed sheet piles. Steel sheet piles are enhanced in durability by corrosion protection measures such as painting and cathodic protection. Steel is the most common form of sheet pile because it has good resistance to high driving stresses, excellent watertightness and can be increased in length by welding or bolting. They are connected by interlocking. The four basic forms of steel sheet piles are square section, straight web section, box section and combined section.
An effective alternative to sheet piles for bulkheads, seawalls and impermeable walls. They are also superior to alternative materials such as concrete and timber. The main advantage of vinyl sheet piles is that they have excellent corrosion resistance when exposed to seawater and do not oxidise.
These are used for temporary structures and support sheets in excavation work. If used for permanent structures above the water table, they should be treated with some form of corrosion protection. Even with corrosion protection, the life expectancy of timber sheet piles is short and they are joined by tongue and groove joints. Timber piles are not suitable for use in strata consisting of gravels and boulders.
These are usually connected by tongue and groove joints. They are often used for permanent river banks, canals and other marine structures. The pile footings are usually cut at a slope to allow for driving and biting, while the pile heads are completed by pouring cap beams. These precast concrete elements are usually joined by tongue and groove joints. They are relatively heavy and bulky, discharging large amounts of soil during travel. This large volume displacement increases the driving resistance. Handling and piling should not damage the piles and appropriate reinforcement must be provided.
Jiasheng owns types of sheet piles and can be used for a variety of sheet pile installations in all environments. The in-house design allows us to tailor cost effective solutions for each project.
