CMI is constantly introducing new products as low cost solutions to our customer’s needs. Every new and existing product is scrutinized extensively by our engineering personnel to ensure that they will meet and exceed the performance standards our customer’s desire.

CMI’s detailed engineering design program, in conjunction with extensive analytical, field and experimental performance results, provide peace of mind for our customers in knowing that we have thoroughly evaluated and proven the performance of all of our products.

CMI continues to provide sheet piling design innovations through extensive research and development, and relies on a world-class engineering team to establish material capabilities as well as the interaction of stresses experienced in the finished product. It is of paramount importance that all factors of the products performance are analyzed carefully. And although it is relatively simple to determine the moment capacity of a sheet piling relying solely on coupon tests and simple engineering calculations, this type of analysis can provide misleadingly high results.

Our products are not only designed with a simplified theoretical overall bending strength, but all aspects of cross sectional loading and buckling as well as ancillary stresses and deformations are analyzed and tested by advanced computer modeling and Finite Element Analysis techniques by both internal and third party engineers.

Finally, finished product performance is proven through extensive internal and third party testing of both material coupon cut outs, and full length full product sections.

· Finite Element Assessment of Two Interlocking PVC Sheet Piling Designs by The Ohio State University
· C-Loc Sheet Piling FEA Analysis by Product Design Center
· Full Section Deflection Testing of Sheet Piling by Crane Component Company
· Evaluation of Deflection of Sheet Piling by the Ohio Department of Transportation
· Flexural Modulus Evaluation by FTI/SEA Consulting · Evaluation of ShoreGuard Rigid Vinyl Sheet Piling by BF Goodrich Company
· Strength Evaluation of Sheet Piling by Science Applications International Corporation
· Deflection Analysis of ShoreGuard Sheet Piling by Materials International
· 16-year Creep Study of PVC by Brown University
· U.S. Army Corp of Engineers, CMB Report 02-008, Results of Vinyl Sheet Pile Materials Investigation for New Orleans District by Joe G Tom and Judy C. Tom
· 1,000 hour QUV Test (ASTM G53-96) by the Illinois Department of Transportation, Bureau of Materials and Physical Research · Physical Property Retention - 5 Year Weathering Study by BF Goodrich., Cleveland, OH · Evaluation of BF Goodrich Geon Vinyl for Use in Plastic Sheet Piling System by BF Goodrich Company, Advanced Engineering and Design Laboratory

The structural performance of all materials is primarily controlled by two main factors:

Stress (σ) – Applied force over a given area. Usually given in pounds per square inch (psi), or pascals (Pa) Strain (ε) – The amount of deformation or stretch of a material. Usually given in inch per inch (in/in) or percentage (%)

Stress and strain for isotropic materials are related by Hooke’s law:

Where E is the modulus of elasticity and usually given in pounds per square inch or pascals.

Therefore E is a number that describes the amount of stress required for a unit elongation, or more simply put the stiffness of a material.

The maximum amount of stress or strain a material can with stand before failure are known as:

Ultimate Stress (σult)
Ultimate Strain (εult)

E, σult, and εult are material properties only and are not controlled whatsoever by cross sectional or other shape parameters.

The bending performance of a particular beam is largely controlled by a cross section property known as the second moment of area or more commonly known as the moment of inertia (I).

The moment of inertia is based solely on the shape of a cross-section, or area, and not controlled whatsoever by material properties.

Moment of inertia is calculated as follows:

Where the moment of inertia of area A is calculated about axis x.

The units for moment of inertia are most commonly inches to the power of four (in4), or millimeters to the power of four (mm4)

When a component is subjected to beam loading (i.e. the loading is applied perpendicular to the components longitudinal axis), there is an occurrence known as a bending moment induced in the beam. The induced bending moment is a factor of the supporting and loading conditions only and not material properties or beam crosssection, and varies through the length of the beam.

The loading configuration of a sheet piling wall is extremely complicated, therefore for this section we will examine more simplified loading cases for illustration purposes. Please refer to Fundamentals of Wall Design, a CMI White Paper for more detailed information on sheet piling loading configurations.

For a simply supported beam with a uniformly distributed load (Figure 1), the maximum bending moment occurs at mid

span and can be calculated as follows. Where Mmax is the maximum moment, w is the distributed load, and L is the span. Bending moment can be visualized as a forced applied at a distance or moment arm and is usually reported in foot pounds (ft-lbs) or newton meters (N-m).

The bending stresses induced in the cross section of the beam are primarily tensile stresses in the bottom section reaching a maximum at the bottom edge, and compressive stresses in the top section reaching a maximum at the top edge. The bending stresses can be calculated as follows:

Where y is the distance of the stress element from the neutral axis of the cross section.

To calculate the maximum bending stress, y is replaced by the distance from the neautral axis to the outside edge of the cross section (c).

For a symmetric cross section, c can be assumed to be half of the cross section depth.

In order to simplify calculation the previous equation can be replaced by:

Where Z is known as the Section modulus, and, for a

semetric cross section:

Section modulus is usually reported in inches cubed (in3) or milimeters cubed (mm3), and is a shape property only.

The deflection of a beam is principally a function of the moment of inertia of the beam cross section, and the modulus of elasticity of the beam material. Generally speaking, the higher the moment of inertia and modulus of elasticity of a particular beam, the lower the deflection and therefore stiffer the beam will be in bending.

For the situation noted in Figure 1 in the bending moment section, the maximum deflection will occur at the center of the span and can be calculated as follows:

Where Δmax is the maximum deflection usually reported in inches (in) or millimeters (mm).