Galvanized Steel Sheet Corrosion

               Depending on the applications, steel sheet will need to have an extra layer of protection to help defend corrosion that naturally occurs over time. In order for manufactures and distributors of steel products to ensure the material they are using in their projects will last, the steel is often galvanized. Galvanization is done via a hot dipping method, coating the product in a layer of Zinc.  While the protective coating is designed to further safe-guard the steel sheet’s future, corrosion is a process that is hard to fully avoid. galvanized steel sheet is still susceptible to corroding – whether that be because of natural, chemical or electrochemical conditions.

                The degree and speed of a steel product’s corrosion depends on a few factors – though in the majority of cases will gradually occur overtime.  The type of steel, the thickness of protective Zinc on the steel sheet, and the product’s environment all play major roles in steel sheet corrosion.

Natural Corrosion

              Galvanized steel sheet that has is exposed to the atmosphere and rainwater is likely to corrode overtime. The product develops a natural carbonate on it that becomes brittle and will eventually crack and split. The split exposes a new layer of zinc that will corrode, and it can even corrode enough to expose the base layer of steel to the atmosphere and its elements. 

Chemical Corrosion

               Steel sheet that has been galvanized has the ability to resist corrosion from a number of chemicals it comes into contact with including concrete, lead, tin and aluminum. However there are some chemicals that will reduce the products’ protection to corrosion: plaster and cement with chlorides and sulfates, acidic rainwater runoff, zinc plate condensation, moss, lichen, and pooled water on the exterior of the zinc coating.

Electrochemical Corrosion

              Certain electrolytes that come into contact with the zinc layer on galvanized steel sheet can cause an electrolytic reaction.  Some electrolytes that could have an effect include rain, fog, condensation and dew. In order to avoid the reaction, prevent contact between the galvanized steel sheet and electrolytes as much as possible. Another solution is applying paint to the galvanized product to thwart corrosion of the coating of zinc.

Types of Pipe Piling

               Pipe piling is used transfer the loads of structures from shallow, weak soils unable to support such a heavy foundation to stronger layers that are found deeper underground. Pipe piling is driven into the ground either open ended or closed ended. If it is open ended, soil is able to enter the tube or it is filled with concrete to provide additional support or capacity to the structural foundation. There are several materials available that are used to manufacture pipe piling including: Steel, timber and concrete. Each are equipped with various advantages and disadvantages, and deciding which to use relies mainly on the intended project for the product. Knowing some basic information and which benefits these different materials presents to consumers makes it much easier to choose the product specific to their needs.

Steel

               Steel is a popular choice for pipe piling application because of the many advantages it provides to consumers. One main advantage is that steel pipe piling come in a wide variety of sizes while pipe piling made of material like timber which is usually manufacture in shorter lengths. Steel is a widely-used choice because of its sustainability in hard-driving projects, and it is also easier to drive than other materials – especially through harder soils. Another benefits includes a minor displacement of the soil when steel in the chosen material. While there are a lot of advantages to steel, there also some downfalls. It can be costly and it tends to corrode. It also can present more challenges during delivery and is much louder to drive than a material like timber.

Timber

               Timber piles are constructed of wood, and due to the material wide availability piles made of timber are usually not as expensive as other material like steel or concrete. While the cost of timber piles is definitely an advantage to those utilizing the product, some timber piles – depending on the type of wood used and the source – may not be the most suitable choice for heavier loads. Other advantages to choosing timber include that it is easy to handle and made of wood – a material that doesn’t corrode. Also, in most cases timber pipe piling is resistant to decayed if it is fully driven into the ground but it may require treatment beforehand to prevent damage from decay and insects, which can be a disadvantage to some. Another disadvantage is timber piles are more likely to be damaged during driving.  

Concrete

               Lastly, concrete pipe piling is another available choice. Some positive aspects of choosing concrete are that it is relatively inexpensive and resistant to corrosion – unless utilized in marine applications. It is also a good choice because the length of concrete pipe piling can be easily adjusted to match customers’ specifications and it as a low level of noise as it is driven into the ground. However, on the flip side concrete does have some disadvantages to the consumer. It is hard to handle and transport, and splicing concrete can be a real problem.

What to Know about Pipe Piling

                    Structural pipe piling is a variation of steel used as a driven pile foundation. Having the capability to either be driven open end or closed end makes for a versatile foundation option. If driven open end, soil and other loose materials make their way into the pipe through the bottom. Pipes required to be empty for construction can simply apply pressurized water to remove the loose materials inside the pipe post driving. For closed end pipe piling, the bottom of the pile is covered with a steel plate or even a specially designed steel shoe.

                                    

                    Alternatively, some construction projects require the pipe piling to be filled with concrete. This is done in order to contribute increased resistance to corrosion. Some countries avoid this route altogether in order to cut costs. If this occurs, protection against corrosion is furnished by accounting for a sacrificial layer of steel or by utilizing a higher grade of steel pipe. When a concrete filled pipe piling corrodes, a majority of the load capacity of the pile remains intact from the concrete. In an empty pipe piling the structural load capacity would lost, therefore, no longer structurally sound.

                   Calculating the structural capacity of pipe piling is determined by the strengths of both the steel and concrete, if the piling is concrete filled. Depending on conditions of the construction site and/or building codes, a certain leeway is made for corrosion of the steel piling. 

                   Generally made out of newly manufactured steel, pipe pilings for deep foundation construction can even be made from reclaimed steel. Typically the reclaimed steel is tubular casing that had been used previously in the exploration of oil and gas.

                   On some occasions, the piling is driven into soil that runs a high risk of corrosion. To slow down the corrosion process and protect the steel from rust, either a coal-tar epoxy or cathodic protection is applied. Although, corrosion of the pipe piling is calculated and accounted for when deciding on the size and which grade of steel pipe to use.

Seven Solutions for Cold Rolled Sheet Pile

                      Cold rolled steel has many end uses that make it essential to many manufacturing companies.  Each of the sizes of cold formed sheet pile has a particular purpose to serve in various applications.  Sizes of the pile sections are classified by their measurements and surface areas. 

Z Series Sheet Pile

With five options to choose from, sheet pile sections in the Lightweight Z Series come in laying widths from 24 ½ to 25 inches wide.  Wall depths of these sections range from a few hundredths of an inch less than 4 ½ inches to a few hundredths more than 4 ½ inches.  Overall section area for this series of piles varies between 5 square inches up to 7 ½ square inches.

             Sheet pile sections of the Intermediate Z Series are just narrower than the lightweight pile options, measuring in at roughly 22 inches. However, the wall depth of this series is 3 inches deeper than its lightweight counterpart, roughly 7 ½ inches.  Intermediate sheet piles share a similar overall section area when compared to the lightweight piles, ranging between 5 square inches up to 7 ½ square inches.

            Next in the Z Series sheet pile line is an intermediate heavy option.  These sections of sheet pile are 2 ¾ wider than the lightweight option and 2 inches deeper than the intermediate option.  Sections measure in at 26 ¾ inches wide and 9 ⅖ inches deep.  Average section area for this series is roughly 12 square inches per pile.  That is almost double the section area (in square inches) of the two smaller pile solutions. Intermediate Heavy Z Series sheet piles are also offered in 6 different size sections, whereas the most sizes any other option offers is 5.
                                  
                                   

            Looking for a sheet pile with a depth of more than 10 inches?  Pile sections in the Mid Heavy Z Series fall into that category with a depth of 10 ¾ inches.  Even with a narrower laying width, the area of each pile is similar to that of the Intermediate Heavy Z Series.  The similarity in area is largely due to the increased depth of the mid heavy option. 

            A Heavy Z Series pile is only offered in four section sizes.  With all available choices in this series being virtually similar in laying width and depth, the differences lie within the section area.  Each section is offered with a width of 22 inches long, and a depth of 12 ¼ inches.  The section area of each pile is 12, 13, 13 ¼, and 14 ¼ square inches respectively.  Compared to smaller styles, this series of piling is quite something.

                                               

            Mega Z-18 Series sections are 1 of 2 sheet pile styles that fall into the “heavy duty” category.  Wall depth and laying width of sections in this series are virtually the same across all five options.  Laying width across all solutions is 29 inches while the wall depth is 17 ¼ for each available pile in the series.  Section area per pile makes a drastic jump when comparing mega series piles to the heavy series alternative.  This particular series has an average section area just over 16 ¾ square inches, that is over 4 square inches larger than an intermediate series pile.

            The last series of cold rolled sheet pile is the Mega Z-19 Series.  Each of the four available section options have a monstrous wall depth measuring in just under 18 inches.  Just as there is a uniform wall depth, the laying width is uniform as well at 27 ½ inches for all sections.  When stacking up the Z-19 Series against the Z-18 Series, the Z-19 Series has a larger section area which is barely under 17 ½ square inches.  Talk about a massive steel wall.

        

Conclusion:

            Every size of sheet pile serves a particular purpose in a certain application.  Some situations may require a smaller pile with very little surface area.  Larger projects may be better suited by using a sheet pile that is wide and deep with a significant amount of surface area.  No matter the project, the sheet pile Z Series has something the get the job done.