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Bringing Stability to an Unstable World

With this summer’s extremely wet weather conditions across the country, building access roads is a major challenge.  Muddy, soft ground is causing construction delays when it comes to moving heavy vehicles and equipment over the soft soils.

Presto’s GEOWEB® Soil Stabilization System offers a way to build roads even with these site challenges using low-cost, local fill—and has been doing so for over 30 years. In fact, the GEOWEB system is the go-to solution for many oil companies in remote areas like the Canadian oil sands and the Amazon basin. Recently, EnergyNow Media featured an article on GEOWEB roads addressing the latest access challenges in the energy sector. The EnergyNow article is republished below.


Reprint of recent article written by “EnergyNow Media” (North American Energy Magazine)

Presto Geosystems: Bringing Stability to an Unstable World

Oil and gas is a tricky business. Everything from resource extraction to site management to processing is fraught with difficulties, challenges, and trials. However, one often-overlooked aspect within this industry is that of simply being able to access the resource site in the first place. Once access is established, it’s crucial that there is a clean, stable platform to work on and transport resources back out. As anyone familiar with the industry knows, energy resources are rarely discovered in local, easily accessible areas. Rather, oil and gas drilling most often takes place in the most far-flung reaches of wilderness imaginable, where even constructing safe, reliable roads and working platforms can be a near-insurmountable challenge.

In these situations, Presto Geosystems truly excels.

Established in Appleton, Wisconsin, Presto Geosystems specializes in soil stabilization and cellular confinement technology. In 1978, Gary Bach developed the Presto Geosystems crowning achievement: the 3D geocell. Since then, Presto Geosystems has lead the way in their field, culminating with the most recent iteration of their flagship soil stabilization product: GEOWEB®, which offers the highest and longest-lasting performance of any geocell stabilization system on the civilian market today. The GEOWEB product is designed to handle the abuse from repeated heavy truck and equipment loading over some of the worst, wet soft soils.  Able to use local on-site fill – even sand – makes the 3D geocell system the quickest way to build roads and platforms in remote areas with limited aggregate resources.

“It’s critical that the weld is consistent so that you can count on the strength of these systems, and know how much load you can carry,” Presto Geosystems Director, Bill Handlos, explains. “The tensile strength of the strip is important so that it’s not too stiff, or too soft…there’s a blend that’s just right. This is what we’ve perfected.” It’s this dogged pursuit of excellence that has made the Presto Geosystems name synonymous with quality and stability when it comes to building site access roads, oil pads, work platforms, surface pipeline protection, construction mats, and much more.

In addition, Presto Geosystems works to provide project support from the very inception of an endeavour all the way up to the completion of a satisfactory installation. “We shine because we’re willing to start during the project conception and vision,” Handlos states proudly. “We do a lot of work with engineers to define the problem and give them evaluations to get them started. As (loadings) become more defined, we often refine and revise designs. We take a journey with our clients without asking for a dime. As they purchase the material, we go to the site with them to give them tips and tricks to help lay down the product faster.” It takes an incredible amount of commitment and dedication to provide so much hands-on assistance even once the product has been sold and shipped out the door, but for Presto Geosystems, that’s simply another part of day-to-day operations.

Providing outstanding levels of client support is one thing, but that doesn’t amount to much if the end product isn’t up to standard. As in all things, however, Presto Geosystems holds itself to an exceptionally high level of excellence and quality when it comes to the materials it develops and advocates for. “We’ve proven that our products work for almost four decades,” Handlos confidently states. “The fact that we invented the product speaks volumes as well. Our models are spot-on in forecasting how the product will hold up, and we have the experience and knowledge to quickly get the product in the ground.”

More than that, Presto Geosystems is made up of team members who have a profound level of respect for the environment, and encourage green practices and policies whenever they are able to. “Our most successful people are those who value the lower carbon footprint that our product creates,” Handlos tells us. “You’re using less natural resources, and saving money all around. We are the green solution, and that matters quite a bit to oil and gas companies, as they are trying to do things with as little impact as they can. We play a role there.”

Ultimately, everything circles back to the outstanding, innovative line of products and services that Presto Geosystems has created and continues to offer to the world stage. “We’re in 60 countries with our products, and are proud to offer free designs for our customers, as clients see the value in these savings,” Handlos lets us know. “We stabilize an unstable world. We are a solution when others won’t work, or are too expensive to deploy. We make it easy to design and construct. We stand behind our product. We’ve set the standards for our industry.

For more information on the pioneering services and products offered by Presto Geosystems, visit them online at www.prestogeo.com, or contact Bill Handlos at 1-800-548-3424 or bill.handlos@prestogeo.com.

Choosing the Right Geocell

Written By: Bryan Wedin P.E., Chief Design Engineer, Presto Geosystems

Not all geocells are created equal. While most manufacturers can provide similar-looking written specifications, you need assurances that the material delivered for your project is of the high quality that you expect. Important factors in the success of your geocell project include:

Quality

The geocell material is proven, strong, and will last

  • Require only the highest quality virgin High Density Polyethylene (HDPE) resin
    • Low quality or recycled resin can lead to weak and/or inconsistent seam strength, putting the success of your project at risk.
    • Non-HDPE materials cannot match the nearly 40 years of in-ground experience of HDPE geocells and plastic alloy proprietary blends can mask cheap stiff filler materials.
  • ISO Certification
    • Important, but the manufacturer sets the testing protocol for the certification. Require a Certificate of Analysis (COA) for the material that is shipped to your project. An ISO certification that does not require continuous testing is lacking.

Integral Components

The complete solution includes proper components

  • Non-corrosive, high-strength panel connection method (ATRA® Keys vs. weak staples or zip ties)
  • Anchors that provide secure connections to the geocell (ATRA® stakes vs. J-hooks)
  • Load Transfer Devices for tendon applications that are non-corrosive and offer a secure connection to the cell walls (ATRA® tendon clips vs. washers, knots or pipes)

Certification

The geocell material “as shipped” meets proven industry standards

  • Insist upon signed material certs showing the proper testing/certification for your application
  • Unscrupulous providers supply special material for testing and ship lower quality material

Design and Specification Support

You receive proper tools and engineering guidance

  • Require the manufacturer to provide project design assistance for their specific material. Variations of resin and of anchoring and connection methods on the market make it “critical that designs from one manufacturer not be used for alternate material.”
  • Require the manufacturer to provide a complete specification/submittal package

Installation Support

The contractor receives proper installation tools and training

  • Many contractors are not experienced in the installation of geocells. Require pre-construction training and on-site field supervision by a certified manufacturer’s representative to ensure your project is installed correctly and economically.

Certainty

Your owner and your reputation are protected

  • All of the above factors combine to provide you the level of confidence you expect from the material you specify. Why risk this certainty for the small savings (savings that come from the use of inferior resin, non-engineered components and a lack of project support) that come with allowing inferior, alternate material suppliers?

 

Bryan Wedin P.E., Chief Design Engineer, Presto Geosystems
P: (920) 738-1342
bryan.wedin@prestogeo.com
www.prestogeo.com

Creep Not a Factor for Geocell Load Support

Written by Matthew Kuester and Bill Handlos, PE

An accurate understanding of creep resistance is essential to proper material selection when using polymers, and in the case of geocells, this science is being misapplied.  The definition of creep deformation is the tendency of a solid material to move slowly or deform permanently under the influence of mechanical stress.  Creep is something that creates fear and uncertainty with all designers where the possibility of creep factors exist. Yes, creep can occur in almost all materials including plastics, metals and concrete.  In cases such as bridge and building design, it is important to properly understand creep factors and account for creep in engineering calculations.  Yet, in the case of designing with geocells for load support, creep factors have no relevance.

What Causes Creep?

In order for creep to occur there must be; a constant load applied and a sustained deformation.  Creep only applies when there is a sustained load on a material for an extended period.  In a case of repeated on and off loading, this would be governed by fatigue and not by creep.  The second required factor for creep to occur is an ability to undergo sustained deformation of the material.  When a polymer has a load applied, the molecules of the material start to pull apart and stretch which leads to elongation of the material in one direction and typically a thinning of the material’s thickness.

Creep not a factor in Load Support

Now, consider a geocell load support application.  The geocell material is expanded out on site and then an infill material is placed into the cells.  At this point, there is not an applied load or deformation occurring in the material.  Next, the infill material is compacted.  This compaction applies a load to the cells, but this load is removed as soon as the compaction equipment is no longer positioned over the cells.  In addition, as an individual geocell is loaded it exerts a force (as it starts to bulge slightly) but each of the adjacent cells around it push back on it (passive resistance) and prevent any sustained deformation.  Thus, at the time of compaction, there is not a constant load nor is there a sustained deformation.  Thus far, the material is successfully installed without any creep effects.

 

After the geocell load support system has been installed, the two types of live loads that will affect the system are driving loads and stationary (parked) loads.  When a vehicle drives over a geocell system the load is applied vertically and as the geocell distributes the load laterally there is a temporary load applied to the geocell material.  The load is not a sustained load and therefore would not have a creep effect.  In the case of stationary loads, the load is continually applied to the geocell so it meets the first criteria for creep.  Due to the pressure from all of the adjacent cells surrounding the loaded cell(s) there is no ability for the cells to move enough to have any appreciable sustained deformation.  Therefore, creep cannot effect this scenario.

ASTM D6992 Creep Test Not Applicable

Those who make claims about potential for creep in load support have cited ASTM standard methodology.  ASTM standards provide an accepted means for standardizing testing to be able to directly compare products.  It is important to review the intention and scope of a test to ensure that it is appropriate and will give relevant results.  The Stepped Isothermal Method (SIM) is used to accelerate creep testing.  ASTM D6992 uses the SIM method to predict the expected deformation of geosynthetics over time when used for reinforcement applications.  This method can be effective yet it is not suitable for polyethylene geocell evaluation.  ASTM D6992 5.3 Note 1 states, “Currently, SIM testing has focused mainly on woven and knitted geogrids and woven geotextiles made from polyester, aramid, polyaramid, poly-vinyl alcohol (PVA) and polypropylene yarn and narrow strips.”  Additionally, the note continues with a warning against expanded scope of the test saying, “Additional correlation studies on other materials are needed.”  So while this test has applicability for geogrids and geotextiles, the test is not intended for evaluating geocells and correlations for polyethylene have not yet been established.

Further, D6992 cannot be considered in isolation.  D6992 states, “Results of this method are to be used to augment results of Test Method D5262 and may not be used as the sole basis for determination of long term creep and creep-rupture behavior of geosynthetic material.”  This reinforces the importance of reviewing each test standard to ensure that the product is within the scope of the test and that the results are relevant and complete.  In the case of geocell evaluation, using ASTM D6992 is inappropriate as it has not been properly correlated to provide accurate evaluation of polyethylene and without ASTM D5262, it provides an incomplete overall evaluation of the product.

HDPE’s Long History of Success and Repeatability

HDPE has been used as the industry standard material for geocells since it was invented over 40 years ago.  HDPE is a material that has been extensively researched by independent scientists throughout multiple industries which allows for a complete understanding of its performance capabilities.  Using a virgin HDPE material allows for direct verification of resin consistency through laboratory testing to ensure that each manufacturing location and production lot have consistent material performance.  This laboratory verification also allows for the comparison of the material to independent scientific results and not just manufacturer’s claims.

Inelastic Materials

A few geocell manufacturers are promoting a Fabricated Inelastic Blend (FIB) to cut manufacturing costs and increase material stiffness utilizing recycled and other unpublished polymer materials.  These FIB based materials can vary widely, even for the same product.  Due to the vast number of combinations possible with these FIB materials, they pose two key problems when included as a material choice: validation and consistency.  Due to the unpublished nature of the blending mixture there is no way to validate this material in comparison with published testing.  Any testing of FIB materials must start from the beginning without any experience to rely on for long-term performance.  The second concern with FIB materials is controlling consistency of the blend.  Because each FIB blend is so variable, there is no way for a 3rd party tester to fully determine consistency of the blend between different manufacturing plants or even between different production lots.  This inability to determine consistency creates uncertainty because there is no way to determine if there has been improper blending or changes to material blend.

Manufacturers using FIB materials promote the advantages of increased material stiffness.  This stiffness is often a function of multiple generations of recycling.  It is important to review the differences between elastic and inelastic materials and how they affect geocell performance.  An elastic material is able to undergo a deformation (strain) and then spring back to its original state without permanent (plastic) deformation.  Conversely, an inelastic material ends in catastrophic (complete) failure.  Many of engineering’s worst failures have come due to catastrophic failures of inelastic materials that were loaded in unexpected ways.  This absolute nature of inelastic failure puts projects at great risk because it does not give indication prior to collapse.  Conversely, with elastic materials as material limits are reached the material will stretch and yield prior to complete material failure.

True HDPE Performance vs FIB Results

FIB materials bring a new uncertainty to the geocell market.  These materials are of unverifiable composition so connecting material to performance is nearly impossible.  Ultimately, these FIB materials beg your trust in their performance touting their unnecessary creep resistance.  They hide the truth that creep resistance comes at a cost – inelastic material that can fail catastrophically.

After 40 years, HDPE continues to be the industry standard material for geocells.  Presto Geosystems’ proudly pioneered the use of HDPE material in its Geoweb products due to the well-understood performance and reliability of that material.

In the 40 years Geoweb has been used for load support projects all around the world, there has never been a failure due to creep effects.  While this consistency of performance may sound very impressive, it should not be surprising because creep forces simply do not matter in these applications.

A Simple Question

How long does it take to install? It is a question we hear every day. When it comes to cost and installation rates for geosynthetic construction products, there are no simple answers to what seems like simple questions.simple questions

In fact, beware of those who try to simplify determination of installation costs for their products with quick answers or charts and tables to determine construction rates. Experienced project managers and site supervisors of the crews charged with installation are in the best position to estimate productivity rates. They know best their crew’s capability and the characteristics of the site involved.

The variables that need to be considered include:

  • Crew size, talent, work ethic and workday length
  • Temperature, precipitation and length of day (sunlight)
  • Experience with product class
  • Size of the project
  • Site Access
  • Site Conditions (see weather)

Crew

The optimum crew size is important. Too small and you may lose the benefits of assembly line productivity. Too large and you will find that you fall over each other and pay for extra “inspectors”. All crews are not created equally. The familiarity with tools and techniques vary greatly as does the work ethic both between crews and by region and country.

Weather

Cold temperature can slow down project installation rates, due to need for heavy clothes and gloves and can even affect the way materials go together. In some cases, frozen ground can aid installation on soil stabilization rates by allowing firm surfaces on which to work. Extremely hot weather can also negatively impact productivity rates. Rain never helps and even recent rain can change a site condition to make working estimates degrade. Sunshine is short in northern climates and visibility can shorten the workday in winter. Delays in projects that push a project start date by months can add days to a schedule as daylight and conditions change by season.

Experience With Product Class

Installation rates do not include training time. Industry leading manufacturers offer trained installation representatives and tools that can help shorten learning curves and get installation efficiency off to a quick start. Size of the Project.

Large sites lead to higher efficiency and greater installation rates. Invariably, installation expertise only matters if the installation duration > learning curve duration. Large projects also offer opportunities to stage work, use multiple crews, and create repetitive motion improvements.

Site Access and Site Conditions

Not only is close proximity to the roadway important, but one must consider the benefits of multiple access points if available. Location of material storage can create long sub delivery times within a single site. Long narrow sites can be a challenge as leap frogging workers is not practical and may force linear progression.

So, when we are asked what installation rates can be expected for Presto Geosystems® GEOWEB® road, slope or retaining wall solutions; or when we are asked about the time to assemble our GEOBLOCK® or GEOPAVE® porous paving systems; or when a customer wants to know how long to assemble a GEOTERRA® construction mats; expect the questions to start….Just a few simple questions.

Our experts are here to help answer your geosynthetics questions. Meet the Presto Geosystems team >>

Seven Key Factors to Choosing the Right Geocell

Written by William G. Handlos, P.E.

Choosing the Right Geocell

Does excellent quality and support matter to you? Of course it does. But, you are smart enough to know that there is no free lunch. Low cost alternatives are less expensive for a reason. So, what do you need to look for to recognize the right geocell for your project?

GEOWEB

1.  Quality Feedstock

Insist upon verifiable proof that your geocell is manufactured only with virgin high density polyethylene. While it is possible to achieve poor weld strength with virgin materials, it is impossible to achieve consistently excellent weld strength unless only virgin high density polyethylene is used.

2.  Integral ComponentsA geocell slope failure

Choose a geocell that offers connection components, tendons, stakes, load transfer clips and installation tools that are specifically tailored for the system. Using rope, staples, bent rebars (J hooks) and zip ties that are not specifically designed for use with a geocell engineered solution is unwise and potentially catastrophic. Use only designs that recognize the critical nature of these components to the overall success of the project.

3.  Experience and Warranty

Choose a manufacturer who has thousands of projects and decades of experience. It is shocking how little some manufacturers understand about the principles and practices of engineering and soil stabilization solutions. Consider the value of a warranty offered by a company who just appeared on the scene or from private label pass through companies who source from numerous suppliers (unknown to you). Pass through private label resellers source from different manufacturers (from different countries) and you have no ability to control the quality of your material if you don’t know where it is being made. The value of a warranty is directly proportional to the stability and longevity of the company offering it.

4.  Certification and Testing

Look for indications of product quality such as CE marking or manufacture certification under the ISO 9001 standard. Ask for proof of certification to make sure that you are not buying “empty acronyms”. Insist on a Certificate of Analysis (COA) that certifies the resin lot number, seam peel strength, and other key criteria of your geocell run to ensure the material shipped to the jobsite meets printed specifications. Everyone has a spec sheet. The value of a spec sheet is that it represents the characteristics of the product. Does the material that shows up at the site meet those specs? Make sure that higher quality “special run” material is not used for testing, while lower quality material is shipped to the job site. Test samples should be taken from warehouse floors, not made special for testing requests.

5.  Design Support

If your geocell provider does not employ full time engineers and provide free design evaluation….ask yourself, why not? Excellent geocell manufacturers are solution providers….not just material mills.

6.  Installation Support and Distributor Network Strength

Contractors should insist that their resellers be trained in construction methods so that geocell is properly placed and so that the contractor can get in and get out quickly. Good providers have tips, methods and custom tools to speed installation. Great manufacturers care about installation……not just moving material.

7.  Certainty

There should be no question about any detail and NEVER a question about the success of a project. Contractors and engineers deserve reputation assurance. Insist upon only geocell providers who are market leaders and who champion the category.

Follow these guides and you will sleep well knowing that your project will be a success.

Impervious Gravel vs. Porous Aggregate Paving Systems

Written by William G. Handlos, P.E.

For two decades, I held the position of City Engineer and frequently had to explain to disbelieving homeowners, developers and elected officials – that gravel driveways and parking lots were not porous. I would explain that for purposes of stormwater runoff, such gravel pavements must be treated exactly as we would concrete and asphaltic pavements. They often bristled at the idea that gravel did not percolate water and were upset to find that their gravel driveway, lots and roadways were assumed to shed 100% of rainwater.

So it is with more than a dose of irony that I now have found myself in the position of regularly explaining to local and state officials that aggregate pavements are not necessarily impervious. Stakeholders are so accustomed to repeating the impervious gravel mantra…that they forget to notice that porous aggregate is not the same thing as gravel. I think it is best to start with a primer on the vernacular.

Good Gravel and Good Porous Aggregate

A “good” gravel (Image 1) should have 40 to 70% stone, well-graded from 1/4” to 2-1/2” diameter; 20 to 50% sand; and 10% +/- fines. It should resist abrasion, shed water and be capable of being compacted.

A “good” porous aggregate (Image 2) should be poorly-graded from 3/8” to ¾” diameter; with 25 to 40% porosity. It should pass the heaviest of rainfall, is easily rutted/shoved and nearly impossible to suitably compact. Such good porous aggregate is often called open-graded base course (OBGC) when used under pavements.

Some municipal and state regulations continue to deem aggregate surfaces as impervious. This is due to inertia and old school thinking and it is past time to change these outdated standards. With the help of engineered high density polyethylene containment products, such as the GEOPAVE® porous paving system, OBGC porous aggregate can be stabilized to offer a highly porous, strong, abrasion resistant, rut proof, aesthetically pleasing and inexpensive alternative to porous asphalt or pervious concrete.

Injection molded and designed specifically for use with open aggregate designs, this system confines the otherwise unruly OGBC to individual cells with an attractive herringbone wall pattern that is designed to be seen and is reminiscent of a paver system. Resistant to frost heave when placed over an OGBC base for storage or sandy soils for fast infiltration, the system gives a very low cost alternative that is highly sought after by those municipalities seeking to meet demanding stormwater goals.

GeoPave® Porous Pavement System

Check to see if your local or state regulations allow for Porous Aggregate Systems and, if not; send a note to info@prestogeo.com with your location, the regulation, and a contact at the agency. We will follow up on all requests personally.

Porous Pavement Systems in Extreme Weather

Porous Pavements

Customers are always coming up with new applications for our GEOBLOCK® Turf Protection System, but the University of Wisconsin-Madison just took it to another level. In early 2014, their Space Science and Engineering Center purchased the GEOBLOCK® Pavers to aid in staging their ice coring drills in Greenland and Antarctica.

The GEOBLOCK System was utilized for two specific applications.

The first application was for a footer under the frame of the drill tent(s). This application allowed the weight of the drill tent building to be distributed across the snow’s surface and provide support. Due to the GEOBLOCK System’s rigid design and load transfer tabs, the same characteristics that make it a strong, durable turf protection system, also delivered value over snow.

GeoBlock® Porous Pavement System

In the second application, the GEOBLOCK Units served as a flooring system inside the drill tent. Researchers liked the grid surface as it provided a non-skid surface and easy installation at sub-zero temperatures (-40°F). The rigid design also wasn’t affected by on-site drilling fluids (due to the non-reactive and inert polyethylene construction).

The GeoBlock® Porous Pavement System Works With A Variety of Infills

Researchers also capitalized on the light-weight design and reusability. The remote location required air-lifting the material and hand construction. The GEOBLOCK® system proved it can deliver results, even in the most extreme conditions.

Learn more about the GEOBLOCK Pavers >>

Request a Quote >>

The Market for Lightweight Construction Mats

Written by William G. Handlos, P.E.

Lightweight Construction Mats

Construction access in soft soils present a common challenge engineers and project managers face while attempting to complete a project on-time and within budget while avoiding scheduling delays and associated costs. These soft soil sites may also be located in remote, difficult to access areas making construction impossible without a good site access system. Popular construction mat systems are made out of a range of materials including timber, laminate, steel and composite mats. They can be effective, but are also costly. They can also put laborers at risk as they require heavy equipment to install. The ideal mat system for access road construction would be designed to have a high utility-to-weight ratio and would deliver an eco-friendly alternative to current technology.

A lightweight construction mat system made from high density polyethylene (HDPE), GEOTERRA®, was created by Presto Products in 2003 to meet the needs of major oil and gas companies working in remote areas of the Amazon jungle. Transporting materials to these sites by helicopter precipitated the need for light, yet strong mats for work platforms and roadways. As the first of its kind, the mats capitalize on the sustainable characteristics of recycled polyethylene and offer an efficient, lightweight design for a variety of remote access applications.

The GeoTerra® Portable Mat System is an efficient lightweight construction mat system.

Lightweight portable mats are easy to deploy and install without heavy equipment, even in remote areas such as for oil & gas access and platforms.

Typical construction mat applications include working platforms for oil and gas exploration as well as maintenance and access roads to transmission lines, pipelines, wind power generation, and mining operations. In addition, construction mats have also been used in a variety of other applications including walkways in soft soils, storage pads and helipads. The GEOTERRA® mat system may also be used as a tracking pad to remove excess soil from vehicle treads. This may mitigate problems associated with the use of traditional aggregate tracking pads which are difficult to work with, costly and hard to remove.

Lightweight HDPE mats are installed without heavy equipment. This decreases the risk of injury and minimizes equipment needs for construction site access. Utilizing a steel torsion tightened “PadLoc®” these mats provide strong connections for load transfer between sections and may be pre-assembled for quick installation in remote site applications.

This lightweight mat system does not degrade, weather, or leach into the subsurface as it is made from up to 97% recycled polyethylene. The ability to dissipate pore water pressure over the existing soil is essential to providing a safe, dry working surface for construction equipment and workers. The high strength geotextile underlayment eliminates soil upwelling in open cells and will allow the system to “float” over poor soils If the underlying soil is pervious, the open cell mat design allows it to act as a porous pavement which reduces the necessity for extra drainage components. If that is not the case, a one or two-sided geocomposite may be used in conjunction with the mat system to effectively direct the precipitation off of the working surface.

The GeoTerra® Portable Mat system helps bridge soft. organic, soils while supporting heavy loads

The strong, permeable mats effectively bridge soft or organic soils while supporting heavy loads.

Even the most difficult site challenges can be overcome by combining lightweight portable mat systems with the correct under layer and anchoring system. Very soft soils with a CBR (California Bearing Ratio) of two or less may require additional load support which may be provided by cellular confinement (geocell) systems.

The Dangers of Breaking Specs and Bid Shopping

Get what you signed up for, hold your specification

HOLD YOUR SPECS

Written by William G. Handlos, P.E.

Specifying Engineers and Architects work tirelessly to build plans and specifications that capture the essence of their vision as they work to write the guiding documents for their project. They make decisions about product types, grades, and take great pains to build into their documents citations of certifications and standards to assure only quality materials are allowed on the site. Yet, when challenged to accept “or equal” substitutions, it seems that all the standards of care can sometimes be lost and substandard materials seem to too easily find their way onto the site.

The reason for this lapse is often a result of the timing of the hand-off between the design team and the project management team occurring just as the contractor award occurs. Contractors are concerned about leaving too much money on the table (the difference in value between the winning and the second bid). Just moments after the bid opening or notice of award, bid shopping commences. Bid shopping on publicly-funded projects is disallowed by legislation in some localities, but even when formally disallowed, informally it occurs widely.

With the economic power of the project award and with the pressure of the potential to lose work, suppliers and subcontractors are often asked to re-quote materials. This is also the point of “specification slide”- when substituted, knock-off material providers join the game with inferior products that do not exactly meet the specification, but are promoted as equals. A busy professional may not have intimate knowledge of the factors to know the difference, doesn’t have the time to do due diligence, or feels pressured to accept the substitution or alternatives.

Close enough may be acceptable for some sites, but when you consider complex and critical civil works projects, the differences in design strength and performance could be the difference between success and failure. There may also be components of the complete “system” solution (e.g. connectors, load transfer devices or customized accessories) that contribute significantly to the design strength and speed of installation that all providers cannot provide. These providers simply jury rig together their version or ignore appurtenances altogether yet still offer the cobbled together system as an equal. The problem with this approach is that either the contractor finds out at the site that assembly was not considered or worse yet that the “or equal” product or system’s weakness does not get revealed until put into service. When the project fails to perform, when the slope erodes, when the pavement fails, or when the channel fails………who pays the price? The contractor pays as he is drawn into extra days and rework. The specifying engineer or the project manager gets hurt by reputation. Most of all, the owner loses, as he gets less value for his money and has the consequences of a failure on his hands.

You put thought and hard work into your P,S&E….Holding your spec is the right thing to do for everybody.

Need design or installation support? Speak with our design engineers today at 920-738-1328 or email.