The termTablestacasrefers to any type of retaining wall that a) is installed in the ground by ramming or ramming rather than pouring or grouting, and b) has a relatively thin cross-section and is light such that the weight of the wall does not support the stability of the wall.
The modern sheet pile industry is just over 100 years old and perhaps the most significant changes in terms of product type and selection have occurred since the early 1970's. Sheet piles have been used in a wide range of applications, most notably in bulkheads and levees. space is limited. Next to this, a special type of retaining wall is the cell box, which is widely used for both temporary and permanent construction.
Sheet piles are made from a variety of materials. The material chosen depends on several factors, including strength and environmental requirements. The designer must consider the possibility of material degradation and its impact on the structural integrity of the system. Most permanent structures are made of steel or concrete. Concrete can offer a long service life under normal conditions, but has a relatively high initial cost compared to steel sheet piles. They are more difficult to install than steel posts. Long-term field observations show that when properly designed, steel sheet piles offer a long service life. Permanent installations must allow cathodic protection to be retrofitted before excessive corrosion occurs.
1. MADEIRA
Thousands of years ago logs were driven or hammered into the ground to serve as rough retaining walls or dikes. Sometimes parallel rows of logs were set up and the center filled with earth to form a stronger wall. The logs were probably tied together with rope and a strong backing was added to combine the logs into a wall. Eventually, it was found that sawn and profiled logs fit better and lose less infill through the joints. This led to the first sheet piles being manufactured with a positive locking mechanism between each sheet pile.batteriesThey consisted of three flat pieces of wood. The middle section was offset from the outer sections, creating a tongue and groove for connecting adjacent piles. A variation on this system was a single piece of wood with the tongue and groove cut to the correct shape. Wakefield style sheet piling is still in use today (see Figure 1). Many timber sheet piles follow the "Marina Wall" design concept, which transfers loads to the log and uses standard-sized timber ridge piles for cladding.
Locking systems for timber or concrete sheet piles were based on the tongue and groove concept. This method serves to keep the wall flush while providing a longer path against leachate with more potential contact points than a simple butt joint. The efficiency of such connections depends on good installation practices, but long-term effectiveness is often compromised by wave action or settlement. The development of filter fabric membrane material to line the back of these walls has reduced the need for more positive interlocks in walls made with these products. As a result, many flat timber bulkheads are constructed of full-size timber. important position in the industry and offers relatively inexpensive bulkheads for homes, commercial properties and marinas. Wood panels are also commonly used in support work for shallow trenches and cofferdams where water intrusion is not a concern.
2. STEEL CUT STACK
Sheet piling was a natural step in the development of this product as we entered the 'Iron Age' in the mid 19th century. Cast iron has been used to make some rough cuts but they have not been successful due to lack of ductility. Around the turn of the century, Bessemer steel was developed and the plants began hot rolling I-beams, U-profiles and angles.
among other structural forms. Freistadt type piles appeared around 1890 and were made from a section of rolled canal as shown in Figure 2. Z-bars riveted to the web provided a slot into which a channel flange could slide, forming a rudimentary but innovative lock. A 'Universal' type sheet pile introduced in Britain around 1895 used hot rolled I-beams and special brackets to connect the flanges of the I-beams. The efficiency of this wall was low as the I-beams were oriented in opposite directions - structurally .
2.1. LARSEN FORMEN
The inventors strove to develop a sheet pile that had locks rolled into the beam during the manufacturing process rather than later attached with rivets. Gregson (USA) patented a piston-jaw locking mechanism in 1899; however, this resulted in the production of a low profile with a relatively low modulus of resistance. Trygve Larssen received a German patent in 1904 for a hot-rolled deep section that greatly increased the strength and efficiency of steel walls and represented a breakthrough. The Larssen sheet pile assumed a "wave shape" when assembled and all subsequent developments for efficient sheet piles are based on this concept. The Larssen section still contained a partially manufactured lock, and it was not until 1914 that a rivetless Larssen interlock appeared in Germany.
In the United States, as early as 1910, Lackawanna Steel Co. (later acquired by Bethlehem Steel Corp.) had a flat sheet pile design and various arch types with integral roller locks. Carnegie Steel Co. (US Steel Corp.) offered three sections flat with rolled latches and one fabricated section. In 1929, the Carnegie Catalog illustrated four deep arches, two shallow arches, and two straight sections. Some of these and other historic sheet pile sections are shown in Figure 3.
2.2. Z-FORM
The Z-shaped piles followed Larssen's concept for an undulating profile, but with the added benefit of serrations being formed in the outer members of the section. It's best to use extra metal as long as it's far from the neutral axis of the wall. The Larssen locks are on the neutral axis. Surprisingly, Z-shaped piles were made in Europe as early as 1911. Ransome's profile closely resembled some of today's lightweight Z-shaped piles. Introduced around 1913, the deeper lamp Z-stack resembles a modern ball-head Z-stack.
In Europe, Z-type shapes fell out of favor when Larssen's U-types were developed. Two forms of the Z were introduced in the United States in the 1930s and became very popular. The PZ-38 and PZ-32 offered wider and deeper sections than any bow shape available at the time. Z-shaped piles gained prominence in the US due to the long-standing controversy over the actual moment strength properties of arch and U-shaped sections.
Z-shaped spigots fit into the ends of the wall, forming a solid web connecting the two flanges. When the PZ-27 section was introduced in the 1940s, it was 30.2 inches.3/ft was almost triple what was published for the arch section with the same weight per square foot of wall. This section later became the most popular sheet pile section in history. Z-Forms are now made with section modules from 8.6 to approximately 85 inches.3/ foot of the wall.
Z-Pile is primarily used in flood and retaining wall applications where flexural strength drives the design and deflection (rolling) between shells is not required. Most manufacturers guarantee no sway, although some can usually be achieved or the plane built up by providing some curved parts as you go. Curves in the wall alignment can be executed with bent or prepared corners. Typical configurations are shown in Figure 4.
Z-piles are not used in applications where locking force is required, such as B. filled cells. These sheets would tend to stretch and flatten out in these cases. For this reason, no minimum detent resistance is offered. If latch tension is the primary design consideration, a cambered or straight bar should be used.
23. DIRECT WEB SECTIONS
Flat sections were originally made only because of rolling limitations. Competition and customer demand led to expansion into structurally efficient sheet piles. It has been found that these flat sections have a tensile strength that is advantageous for the construction of circular structures filled with sheet piles. Around 1908, on the Black Rock River in Buffalo N.Y. built a cofferdam for large cells. to drain water from the site to a new lock. This concept was successively expanded to include circular and membranous cells for piers and breakwaters, which may have been previously built on wooden or masonry cradles.
The use of large-diameter cellular cofferdams received a particular boost in the 1930s when the Tennessee Valley Authority initiated a series of hydroelectric power plants and naval blockades on this river system in the southeastern United States. TVA engineers not only developed new design methods to create these large structures, they also developed better ways to install and maintain them.
Flat panels have low strength to resist bending, but have very strong interlocks to resist "edge" stress. Thosebatteriesthey are used almost exclusively to build large filled cell structures. The flat plates must provide some "wiggle" ability between the plates in order for a circle to be completed. Most manufacturers guarantee at least 8 to 10 degrees of wobble between adjacent planks at standard pile lengths. In the case of overly long pieces, these guarantees usually have to be negotiated.
For a shatterproof design, the available toothing resistances must be known in advance. Most manufacturers guarantee a "minimum" locking force based on tensile tests on several representative production samples. Experience has shown that interlocking dimensional tolerances that are within certain limits provide characteristic stress levels throughout the production cycle. Flat sheet piles are only available as a hot rolled product as the cold finishing process does not provide a lock with sufficient tensile strength. Locking forces were gradually increased due to the requirement to build larger cells for deeper cofferdams.
flatterTablestacasIt was used to build temporary cellular cofferdams. After first use, the sheets are removed and used elsewhere in the project, or perhaps sold to another project elsewhere. Other flat plates are used in permanent structures such as breakwaters, earth containment sites, piers and other applications. Cellular cofferdams are discussed in more detail in 1.2.1.4.
2.4. COLD FINISHED STACK
Since the early 1970's, a different method of manufacturing steel sheet piling has greatly expanded the availability and choice of sections. This new process uses coiled hot rolled sheets that are fed through a series of cold rolling stands to form complete "Z" or "arc" shapes with a simple hook-type interlock. This is a relatively cheap capital outlay compared to hot rolled products and has attracted many new manufacturers. These steel piles are cold-formed flat sections with a constant thickness of less than 0.25 inch and are manufactured in accordance with ASTM A 857. Yield strength depends on thickness and ranges from 25 to 36 kips per square inch (ksi). These profiles have a low section modulus and very low moments of inertia compared to heavy Z-profiles. Special coatings such as hot-dip galvanized, galvanized and aluminized steel are available to improve corrosion resistance. Lightweight piles should be considered for temporary or smaller structures. Light piles can be considered for permanent construction if accompanied by a detailed corrosion study. Field testing should include at least pH and resistivity measurements.
See Figure 5 for typical light meter sections.
2.5. HIGH MODULE SECTIONS
There is a limited but continuing demand for sheet piles with strength properties exceeding those available in standard products. These may be required for deep excavations, poor ground conditions, deeper excavator lines and other special conditions.
2.6. NOMENCLATURE AND IDENTIFICATION OF PLATE PILOTS
North American sheet pile manufacturers have standardized the identification of sheet pile sections so that they can be specified without reference to a particular manufacturer's product. The marking included a "P" (stack), "Z" (type or shape) and "27" the weight or PZ-27. Domed and flat shapes have been described similarly. Outside the US, cold finishers have their own "in-house" identification systems. Now there is no universal naming system. It is now common practice to specify the bending moment to be maintained, giving the contractor considerable flexibility in selecting a profile and supplier. This bending moment specification should not be used blindly, however, as many sheet pile designs (particularly those using vinyl sheet or pultruded fiberglass) are primarily driven by deflection.
2.7. CUTTING PLATES ORDER
Like other steel products, steel sheet piles can be ordered to a standard specification. In the United States, this standard is published by the American Society for Testing Materials (ASTM) 1916 Race Street, Philadelphia, PA 19103-1187. The basic specification ASTM A-328 and other listed specifications can be obtained in writing from the Society or on its website.//www.astm.org.
This specification includes the steelmaking process, chemical requirements, minimum performance and maximum strength. Delivery is mentioned in the ASTM A-6 specification. The ASTM specification does not cover spline tolerances, straightness, spline strength, or loaner or used goods. These lie between buyer and seller.
Other specifications are:
- Canadian specification CSA 44W, CAST 44W/70
- British Specification BS4360 - Various Grades
- European specification: ST SP 37; STSP 45; STSP 5.
2.8. TODAY'S STEEL CATCHES
Although the annual consumption ofTablestacasIt rarely exceeds 250,000 US tons in this country, the number of producers and the availability of profiles has increased dramatically in the last ten years. In 1960 there were two manufacturers in the USA each offering nine sheet piles. Today there are at least 14 US and non-US producers offering more than 200 sections in this country. Competitive factors have led to the development of new, wider and more efficient sections. Large Z-shapes are now available for deep designs with a section modulus nearly double that previously available. A wall system was developed using large H-profiles in combination with lightweight Z-profiles, which greatly increase the modulus of the profile. Lightweight "gauge" material is produced in cold-form mills for economical working in shallow trenches and bulkheads.
Higher strength steels up to a yield strength of 60 ksi have also been used successfully on sheet piling projects. These grades offer the opportunity to save weight or increase bending or locking strength over traditional grades. Stainless steel can also be specified for applications that require it.
3. CONCRETE
These piles are prefabricated panels ranging from 6" to 12" deep and 30" to 48" wide and come with tongue and groove or mortar joints. After driving, the mortar joint is cleaned and grouted to create a reasonably watertight wall. A notch at the bottom of the stack, toward theBatteryProgress, forces one stack against another during installation. Concrete sheet piles are generally prestressed to facilitate handling and driving. Special angle and corner profiles are usually made of reinforced concrete due to the limited number. Concrete sheet piles can be advantageous in marine environments, highly abrasive riverbeds and where the sheet piles must carry significant axial loading. Past experience shows that this pile (due to its own weight) can cause settlement in soft foundation materials. In this case, most likely, the tightness of the wall will be lost. Typical concrete cross-sections are shown in Figure 6. This stake type may not be available at all locations.
4. LIGHTWEIGHT ALUMINUM
Aluminum sheet piles are available as interlocking corrugated sheets of either 5052 or 6061 aluminum alloy. These profiles have a relatively low section modulus and moment of inertia, requiring assembly in most situations. A Z-profile is also available in 6" deep and up to 0.25" thick. See Figure 7 for typical sections.
5. VINYL-SPUNDBÄDEL
Vinyl sheet piling is a relatively new type of sheet piling that can be used in a variety of ways for ship walls and other sheet piling applications. It is generally made by continuous extrusion. The raw material, made of synthetic resin, is melted and pressed through a die. This die forms the plastic into the cross-section of the computer-aided design. The sheet is then cooled and cut to size. The panels can be extruded to the required length for various retaining wall applications.
Vinyl wrap comes in many configurations. The most common configuration is a type of Z-blade configuration similar to that shown in Figure 4. Others are similar to the aluminum sheets shown in Figure 7. Individual sheets have interlocking tongue-and-groove edges. Interlocking edges are extruded as part of the panel to ensure uniform strength throughout the retaining wall. As with other panels, vinyl panels require transition parts such as corners and crossings. These are designed to connect properly with the manufacturer's other blades.
Vinyl sheeting is made from modified polyvinyl chloride (PVC), making it suitable for most marine environments and not subject to leaching, corrosion, or similar degradation mechanisms. The technology that brought us vinyl siding for homes, plastic automotive parts like bumpers and dashboards, and durable appliances is now being used to make sheet piles for ship retaining walls, seawalls or bulkheads. The vinyl also contains a UV stabilizer to reduce deterioration from sunlight.
why vinylTablestacasBecause they generally have a low modulus of elasticity and strength compared to steel sheet piles, deflection often becomes the determining factor in wall construction and must be determined in the design process.
6. PULTRUDIATED FIBERGLASS LEAF
Pultruded sheet pile is a section of pile manufactured by the continuous processing of raw materials by drawing resin-rich reinforcements through a heated steel die to form profiles of constant cross-section and continuous length. The first reinforcement used in the profile is continuous glass fibers called "roving". The glass wick runs the full length of the pultruded profile and gives the shape its "longitudinal strength". To add multi-directional reinforcement, a continuous glass mat is added. The wick and mat now run through a resin bath in which the glass fibers are saturated with a liquid duroplastic resin. This process is commonly known as the "wetting" process.
The coated fibers are then brought into the right shape by a mold guide and finally fed through a heated nozzle (curing). Upon exiting the tool, the pultruded form is cooled and the resulting high strength reinforced composite sheet pile is cut to size.
Pultruded sheet piling is suitable for a variety of light duty bulkhead applications. As with vinyl sheeting, deflection is often the determining factor in design, although the strength of the material is many times that of vinyl.
More information can be found here.