Retaining walls - Steel Piling Group (2022)

Until the advent of the Eurocodes, geotechnical design of retaining walls was carried out to BS 8002:1994, with additional reference to CIRIA 104 ‘Design of retaining walls embedded in stiff clay’.13 An updated CIRIA Guide C580 ‘Embedded retaining walls – guidance for economic design’ was published in 2003. The design approach methodology contained in CIRIA C580 was based on the draft Eurocode 7 in development at the time. Whilst the concepts are similar, the actual design approaches set out in the final Eurocode 7, published in 2004, differ in the detail.

In 2015 BS 8002 was published providing designers with the guidance they need to implement the requirements of Eurocode 7 with regards to gravity, semi-gravity and embedded retaining walls. The standard also gives further details on how retaining structures should be designed according to limit state principles and provides information missing from Eurocode 7 but of importance to UK practice. At the same time, advances in retaining wall technology over the past 20 years are reflected in the fully revised text.

Most recently in 2017, a new guide CIRIA C760 Guidance on embedded retaining wall design was published. This guide is intended for use in the design of sheet pile, king post, contiguous bored pile, secant bored pile and diaphragm walls. It supersedes CIRIA guide C580. This new guide is compatible with the relevant Eurocodes and its range of application has been extended to include soft clays and weak rocks.

Structural design of steel sheet pile retaining walls is carried out in accordance with Eurocode 3 Design of Steel Structures Part 5 Piling, replacing BS 5950 ‘Structural Use of Steelwork in Building’.

The design guidance documents mentioned above are primarily for land based structures. However, maritime structures form an extensive market where steel piling solutions are most attractive. Hence for specific design requirements for maritime structures (quay walls, cofferdams etc) reference shall be made to BS 6349-2.

Sheet-piled walls

Steel sheet piles are the most widely used embedded retaining wall elements in quays and jetties. They are relatively light and easy to handle, they can be supplied in long lengths and can be extended and cut without undue difficulty.

(Video) Retaining Walls Explained | Types, Forces, Failure and Reinforcement

NOTE 1 Guidance on the installation of steel sheet piles is given in BS EN 12063, and this includes guidance on welded joints and many other issues.

This type of pile can be driven to considerable depth with low displacement in a wide range of ground conditions and into weathered rock. Where hard driving is encountered, the pile section required might exceed the section needed to resist bending. This should be taken into account in assessing the reduction of moments. With various forms of pre-treatment, steel sheet piles may also be installed in solid rock, in a trench backfilled with concrete, by pre-splitting the rock or by the use of toe dowels as detailed in BS EN 12063.

The interlocks are generally tighter than for timber or concrete piles.

The principal disadvantage of steel sheet piles is corrosion, however this can easily be allowed for in design, see the durability section for more detail.

Some types of floating fenders can cause abrasion of steel sheet piles or their protective coatings, and this should be taken into account in selecting the form of fendering to be adopted.

The most commonly used interlocking pile sections for steel embedded retaining walls are the U- and Z- types. Several combined wall sections are also available, usually comprising H-piles, box piles or tubular piles with either interlocking sheet pile elements or separate interlocks.

Additional bending resistance can be achieved, where the piles are to be driven to a predetermined level, by welding reinforcing plates to the pile flanges in zones of maximum bending moment.

NOTE 2 Examples of interlocking steel pile sections and combinations of elements suitable for use in embedded retaining walls are given in BS EN 1993-5.

(Video) Retaining wall synthetic sheet pile driving

Construction tolerances should generally be in accordance with 8.13 and BS EN 12063.

NOTE 3 The ICE specification for piling and embedded retaining walls gives further guidance on tolerance

Soldier piles and sheeting

Embedded retaining walls constructed using soldier piles and horizontal sheeting are not widely used in maritime works, owing to the high cost of the diving work involved and the tight constructional tolerances required to avoid loss of backfill. However, this type of wall might be a suitable way to provide a deeper retaining face outside an existing wall, where minimum interference with port operations is essential.

The piles may be of steel or concrete, either precast or in situ: pre-stressing is normally advisable to reduce weight and improve durability. Preformed piles may be installed, by driving or placing in a preformed hole, in any seabed material, but might require an excessive penetration in soft clays and silts. In-situ concrete piles are subject to the usual limitations of bored piles.

The penetration of the piles into the seabed should be calculated to take into account the consequences of failure of the ground support.

The heads of all piles should be temporarily supported until the capping is cast and the anchors installed.

The sheeting in quay walls of this type is usually of precast concrete planks. The sheeting should be secured to the soldier piles to prevent differential movement and consequent loss of material. Figure 1 shows an example of such a construction. Care should be taken to provide appropriately sealed joints to prevent loss of material.

Construction tolerances for soldier piles should be in accordance with 8.13.

(Video) Quantity Management (Special): Interlocking Steel Sheet Piles

NOTE The ICE specification for piling and embedded retaining walls gives further guidance on tolerances.

Combined steel sheet piles

In combined steel sheet-piled walls in which the intermediate sheeting is required to contribute to the bending resistance, welding of the interlocks will in many cases be required. If the modulus of the H-section, box or tube far exceeds that of the intermediate sheeting, it may be assumed that all horizontal actions are transmitted to the large modulus elements and no welding of interlocks is then required. The intermediate sheeting, in the latter case, may be of lighter section than would be necessary if it were designed to span vertically. Soldier-piled walls are also designed assuming that all horizontal actions are transmitted to the soldier piles.

Actions and effects of actions on embedded retaining walls

The actions on a retaining wall are summarized in BS EN 1997-1:2004, 2.4.2 and some or all of these will be appropriate to the design of a specific structure.

The stresses obtained by analysis should be in accordance with BS EN 1992, BS EN 1993, BS EN 1995 or BS EN 1997 as appropriate to the material under consideration. Crack widths (see 4.4.2.3) should be calculated for the serviceability limit state.

These stresses in steel and timber elements should be based on the wall section at the end of the design life.

The maximum bending moment in embedded retaining walls does not usually coincide with the most severe zone of corrosion, and this should be taken into account in the analysis of steel sheet-piled walls.

The geotechnical parameters should be established in accordance with the requirements of BS EN 1997-1 through an appropriate geotechnical investigation. The partial factors to be applied to actions, and the method to be used for combining actions, should be in accordance with Clause 5 of the present standard. The partial factors applied to the geotechnical parameters should be taken from BS EN 1997-1.

The driving of steel sheet and timber piles should be in accordance with BS EN 12063.

(Video) Secant Pile Wall & Vor Der Wand Installation

Where support fluid is used in the excavation of in-situ concrete embedded retaining walls, the permissible bond stress of deformed steel reinforcement might have to be reduced.

Further guidance is given in the ICE specification for piling and embedded retaining walls.

Walings should be designed in accordance with BS EN 1993-5.

Cellular sheet-piled structures

Cellular sheet-piled structures consist of cells formed by interlocking straight-web steel sheet piles, driven or placed with their tops above water level. The cells are filled with granular material. The superstructure may be a solid in-situ concrete capping, or a reinforced concrete edge retaining wall which is backfilled and the top surfaced.

Cellular sheet-piled walls are gravity structures that function partly as cantilever walls where pile embedment can be achieved.

Sheet-piled cells may be founded on soft rock, granular material or very stiff clay. Where soft clays exist, they should be removed before filling the cells. This soft material should be dredged prior to cell construction at sites where the soft material layer is very thick, to avoid causing compression of the cells. Cellular structures may be used for both quay walls and jetties. They use less steel than double-wall sheet wall structures because the steel resists the lateral soil actions in hoop tension rather than bending, and walings, tie rods and bulkheads are generally not required.

This type of structure is particularly liable to damage by wave action during construction without the provision of adequate robust temporary works. This form of structure possesses little resistance to horizontal actions before the internal filling is completed.

Read more about Steel Bearing Piling Design

(Video) Secant Pile Wall Construction Methodology

FAQs

What is piling retaining wall? ›

Sheet piling

Sheet pile retaining walls are usually used in soft soil and tight spaces. Sheet pile walls are driven into the ground and are composed of a variety of material including steel, vinyl, aluminum, fiberglass or wood planks.

What type of piles act as a retaining wall? ›

Steel sheet piles are used for temporary and permanent retaining walls. In temporary works and cofferdams the sheet piles enable deep excavations to be made to facilitate construction below ground and water level of other permanent works.

What is steel piling? ›

Steel sheet piles are long structural sections with a vertical interlocking system that create a continuous wall. The walls are often used to retain either soil or water. The ability of a sheet pile section to perform is dependent upon its geometry and the soils it is driven into.

How long does steel sheet piling last? ›

An average good coating will have an effective life of about 5 or 6 years. Poor coating, including poor workmanship, will fail in less than a year, with the best going to an 8 to 9 year life. Cathodic Protection $360,000. Protective Coatings, using re-coating every 5 years $480,000.

What is retaining wall and types? ›

A retaining wall is a structure designed and constructed to resist the lateral pressure of soil, when there is a desired change in ground elevation that exceeds the angle of repose of the soil. Retaining walls are used for supporting soil laterally so that it can be retained at different levels on the two sides.

What are retaining walls made of? ›

A retaining wall is a structure that holds or retains soil behind it. There are many types of materials that can be used to create retaining walls like concrete blocks, poured concrete, treated timbers, rocks or boulders. Some are easy to use, others have a shorter life span, but all can retain soil.

What is CFA piling? ›

Piling. Request a quote. Continuous flight auger (CFA) piles are drilled and concreted in one continuous operation enabling much faster installation time than for bored piles. Reinforcement is placed into the wet concrete after casting, enabling the pile to resist the full range of structural loading.

When would you use a Secant pile? ›

Typically used for

A secant pile wall consists of overlapping (secant) piles to form structural or cutoff walls and achieve the required water tightness. The design can incorporate steel bar or beams for reinforcement and anchors can provide additional lateral support, if needed.

Can you use corrugated metal as a retaining wall? ›

Corrugated metal can work like any stone or wood retaining wall. It can stand tall, not just make a low wall. This is a vertical patterned corrugated metal sheet that runs along the hilly side of the front yard landscaping.

What are the two types of piles? ›

The two main types of piling are end bearing and friction piles: End bearing piles transmit loads directly to a deeper strong soil or rock layer some way below the surface. Friction piles transfer load by friction between the surrounding soil and the surface of the pile over its full length.

What are advantages of steel piles? ›

Advantages of Steel Piles:

Steel piles have a large bearing capacity. Steel piles can penetrate through stiff layers or boulders. The volume of soil displaced during the driving of steel piles is less. Steel piles can withstand rough handling.

Where steel piles are used? ›

Steel pipe piles and steel pipe sheet piles are widely used in ports/harbors (piers, seawalls, and breakwaters), urban civil engineering (earth-retaining walls and cofferdams), bridges (foundations for steel pipe sheet pile foundations), and other applications, along with widening their applications due to enlargement ...

What are the disadvantages of sheet piles? ›

Sheet pile wall disadvantages are:
  • Sections can rarely be used as part of the permanent structure.
  • Installation of sheet piles is difficult in soils with boulders or cobbles. ...
  • Excavation shapes are dictated by the sheet pile section and interlocking elements.
  • Sheet pile driving may cause neighborhood disturbance.

How deep should sheet piles go? ›

Pile lengths required around the pier range from about 50 feet to 90 feet at the pier's deepest point. The sheet piles installed in the 1980s had deteriorated in many places. The new piles, at 0.625-inches thick, should have a longer service life of 50 to 60 years.

Is sheet piling waterproof? ›

On this basis, a steel sheet pile is watertight in all parts of its structure other than the part which needs to connect to other sheet piles – the interlock. Such interlocks are typically located at 600 to 800mm centres along the length of a steel sheet pile wall.

What type of retaining wall is best? ›

Concrete and Masonry Retaining Walls

Poured concrete is the strongest and most durable choice for retaining walls. It may also be carved and formed to look like mortared stone depending on your taste.

What is the main used of retaining walls? ›

Prevent Erosion

As previously stated, one of the main purposes of a retaining wall is to hold back soil. If the soil slopes downward, it could easily create erosion in the area. Retaining walls can also be used to hold back water.

What is the best material to build a retaining wall? ›

Retaining walls can be made from wood, bricks, natural stones or concrete blocks. For DIYers, it's best to use concrete retaining wall blocks, which can be interlocking and are heavy enough to stay in place without cement or other adhesive. Interlocking blocks fit together and add extra security to the wall.

What material goes behind a retaining wall? ›

Backfill refers to the dirt behind the wall. In order to provide proper drainage, at least 12 inches of granular backfill (gravel or a similar aggregate) should be installed directly behind the wall. Compacted native soil can be used to backfill the rest of the space behind the wall.

What is the cheapest type of retaining wall? ›

The cheapest type of retaining wall is poured concrete. Prices start at $4.30 per square foot for poured concrete, $5.65 for interlocking concrete block, $6.15 for pressure-treated pine, and about $11 for stone.

What is the difference between CFA and SFA piling? ›

CFA piling utilises the same installation principle as SFA, but CFA employs a concrete fill instead of grout. CFA rigs are bigger and better suited to larger sites where they can work continuously.

What are CFA piles used for? ›

Continuous Flight Augering (CFA Piling), also known as auger cast piling, is a technique used to create a concrete piled foundation solution. The CFA process is virtually vibration free and one of the quietest forms of piling, making it ideal for environmentally sensitive areas.

How deep can CFA piles go? ›

Diameters generally within the range of 450mm to 1200mm with maximum depths normally up to 29 metres. Used for bearing piles and contiguous, interlocking and secant piled walls.

How deep can secant piles go? ›

Capability: Depending upon ground conditions, using CFA or LDA technology, we can build from 600mm to 1180mm diameter, to a depth range up to 24m (primary pile) with secondary pile (male) carrying on till 60m, depending upon technique.

What is the difference between tangent pile and secant pile? ›

Primary secant piles are installed first with secondary reinforced secant piles constructed in between primary piles once the latter gain sufficient strength. Pile overlap is typically in the order of 3 inches (8 cm). In a tangent pile wall, there is no pile overlap as the piles are constructed flush to each other.

What is the difference between contiguous piles and secant piles? ›

The piles may be constructed so that they virtually touch each other (contiguous). The gaps between the piles can be grouted to form a watertight retaining wall. Alternatively (secant piles) every other pile may be constructed, with their centres less than two diameters apart.

How long will corrugated steel last? ›

Longevity: Like other steel and metal products, corrugated metal will last much longer than other materials. Regardless of how you use it — inside or outside — you can expect it to last between 40 to 70 years.

How long will corrugated metal last in ground? ›

Where generally standard galvanized coating (610 g/m2) corrugated steel pipe provides a life of 45 years or more, a suitable alternative when such a life span isn't required is coating Z 275.

Does corrugated steel rust? ›

Corrugated metal is also resistant to rusting, so it will keep its desired appearance regardless of the weather. The material is also resistant to rot and mold, so you won't have to worry about the corrugated fence falling apart prematurely or becoming filled with termites.

What are the three types of piles? ›

There are three types of pile foundations according to their construction methods which are driven piles, cast-in-situ piles, and driven and cast-in-situ piles.

What is piles and its types? ›

Grade 1 hemorrhoids remain in the rectum without prolapsing (protruding out of the anus). Grade 2 hemorrhoids prolapse when a person passes stool, then return inside on their own. Grade 3 hemorrhoids are prolapsed and must be pushed back in. Grade 4 hemorrhoids are prolapsed and cannot be pushed back in.

Are there different types of piles? ›

Types of Piles (Haemorrhoids) Haemorrhoids can be grouped into four main types: internal haemorrhoids, prolapsed haemorrhoids, external haemorrhoids, and thrombosed haemorrhoids.

Do steel piles rust? ›

It is important to understand that Steel Piles are made of 'Carbon Steel' that will naturally corrode over time, with the deterioration rate depending on exposure to oxygen, water and accelerating agents (such as salt, contaminants etc.).

How do steel piles work? ›

Piling – The Way It Works

Piling works by inserting large amounts of wood, steel or concrete into the soil of the ground. The deep insertion of these elements ensures a sturdier base for the construction project to take place.

What are steel piles made of? ›

Basically, steel piles are a big screw, made of galvanized steel with a helical flange that not only helps to insert the pile, but also helps secure it into the ground. By using a mini-excavator with special attachments, a drill can enter the ground while measuring the load bearing capacity of the soil.

What is steel sheet piling used for? ›

Sheet piles are most commonly made of steel, but can also be formed of timber or reinforced concrete. Sheet piles are commonly used for retaining walls, land reclamation, underground structures such as car parks and basements, in marine locations for riverbank protection, seawalls, cofferdams, and so on.

What are the three main advantages of steel piles compared to concrete piles? ›

The head-to-head: Steel versus concrete piles

Lighter than traditional concrete piles, making them easier to ship and install. Easier to splice than standard concrete piles, via welding. Used for supporting heavier structures, such as skyscrapers and large bridges. Can penetrate hard layers in the ground.

How do you design a pile? ›

The design of pile foundation involves providing adequate pile type, size, depth, and number to support the superstructure load without excessive settlement and bearing capacity failure. Deep foundations are more expensive and technical than shallow foundations.

How does sheet piling work? ›

The concept of sheet piling is pretty straightforward. Wherever a wall or siding needs to be held back, steel sheets are wedged into the earth at predetermined intervals. The sheets are driven into the soil with vibratory or impact hammers. In some cases they may be installed with hydraulic presses.

What is a gabion retaining wall? ›

GABION RETAINING WALL SYSTEMS ARE MONOLITHIC GRAVITY MASS STRUCTURES THAT ARE IDEALLY SUITED FOR EROSION CONTROL APPLICATIONS AND FOLLOW STANDARD DESIGN METHODS FOR GRAVITY AND MSE RETAINING WALLS.

How are sheet piles installed? ›

The most common methods of installing steel sheet pile walls include vibrating, impact driving, hydraulic pushing, jetting, and trenching. The type of sheet piling often governs the method of installation.

What is concrete sheet pile? ›

Concrete sheet piles are prefabricated to eliminate the necessity for temporary wooden or metal form-work at site. This method can quickly and safely construct a strong high quality prefabricated structural wall. Additionally, this method does not disturb water flow in river and canal work.

What are the disadvantages of sheet piles? ›

Sheet pile wall disadvantages are:
  • Sections can rarely be used as part of the permanent structure.
  • Installation of sheet piles is difficult in soils with boulders or cobbles. ...
  • Excavation shapes are dictated by the sheet pile section and interlocking elements.
  • Sheet pile driving may cause neighborhood disturbance.

What are the advantages of steel sheet piling? ›

Advantages of sheet piling

It is light in weight, making it easy to lift and handle. It is recyclable and reusable. The pile length and design are easily adaptable. Joints are designed to withstand the high-pressure required to drive them into place.

What is steel sheet piling used for? ›

Sheet piles are most commonly made of steel, but can also be formed of timber or reinforced concrete. Sheet piles are commonly used for retaining walls, land reclamation, underground structures such as car parks and basements, in marine locations for riverbank protection, seawalls, cofferdams, and so on.

What is the difference between gabion wall and retaining wall? ›

Classic concrete walls or retaining walls are monolithic, while gabion retaining wall blocks, filled with local material, are more in sympathy with their surroundings.

What are the disadvantages of gabions? ›

Disadvantages/Problems

Gabions are more expensive than either vegetated slopes or riprap. The wire baskets used for gabions may be subject to heavy wear and tear due to wire abrasion by bedload movement in streams with high velocity flow. Difficult to install, requiring large equipment.

What is the lifespan of a gabion? ›

How long do gabion walls last? Gabions are designed to be used in permanent structures but their longevity is directly related to the environment they are installed in. This means life expectancy of gabion walls can be anywhere from 10 to 75 years depending on the install environment.

What are the methods of piling? ›

The two main types of piling are end bearing and friction piles: End bearing piles transmit loads directly to a deeper strong soil or rock layer some way below the surface. Friction piles transfer load by friction between the surrounding soil and the surface of the pile over its full length.

How deep do sheet piles need to be? ›

Pile lengths required around the pier range from about 50 feet to 90 feet at the pier's deepest point. The sheet piles installed in the 1980s had deteriorated in many places. The new piles, at 0.625-inches thick, should have a longer service life of 50 to 60 years.

When would you use a sheet pile retaining wall? ›

Sheet pile walls have been used to support excavations for below-grade parking structures, basements, pump houses, and foundations, to construct cofferdams, and to construct seawalls and bulkheads. Permanent steel sheet piles are designed to provide a long service life.

What is interlocking sheet steel piling? ›

Sheet piles are sections of sheet steel with interlocking edges that are driven into the ground to provide permanent or temporary earth retention and excavation support.

How thick is a sheet pile? ›

minimum thickness of 8 mm for GU 12N, to enhance durability; single pile width of 600 mm; ArcelorMittal Larssen interlock; steel grades from S 240 GP to S 430 GP.

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