Vol. 14 Issue 2 PRACTICAL AND ENTERTAINING SINCE 1997 SUMMER 2011

braunintertec.com

THE POCKET

Consultant

By Scott Freitag, PrincipalBraun Intertec Geothermalsfreitag@braunintertec.com

Ground source heat pump (GSHP) based “geothermal” HVAC systems are rapidly gaining popularity. Given the benefits of low

Four rules to minimize expense and improve reliability of a geothermal HVAC system

operating costs and improved sustainability, it is easy to understand why. However, in spite of the benefits, broader acceptance of this technology continues to face significant headwinds. Construction complications, cost overruns, environmental risks, and, even in the best of situations, less than attractive first costs continue to deter widespread utilization.

Inside the building, heat pump based HVAC technology is nothing new. Many facility owners currently rely on dependable operation from water source heat pump (WSHP) systems. Like GSHP, a WSHP system uses a central water loop to convey heat to and from the heat pumps. However, in contrast, WSHP systems use a fuel fired or electric boiler, together with a water chilling device, to create and reject heat. WSHP systems compare in first costs to other conventional HVAC methods, and can be installed without noteworthy exposure to construction or environmental complications. However, the cost to own a WSHP system is about the same as other conventional methods, and much greater than its GSHP cousin.

In the early 80’s, a company called WaterFurnace International successfully tweaked a water source heat pump to operate using a broader range of entering water temperatures and, in place of the boiler and chiller, connected these new units to plastic pipes buried below ground. As a result, commercially viable GSHP technology was born. Comparably inefficient boilers and chillers were no

longer needed, fuel was no longer needed, and heating/air conditioning costs could be cut in half. All good, right? Not so fast.

Because GSHP technology relies on the earth’s temperature as a key component of the HVAC system, significant variability in deploying the technology was introduced. Today this variability remains the primary reason that the technology is not being used by the masses. GSHP systems require large ground heat exchanger (GHX) systems to derive sufficient capacity to condition a given facility. How large? Roughly, and for most of you reading this article, every 600 square foot of interior space conditioned requires an average of 500 feet of 1-inch polyethylene heat exchanger pipe buried in the ground. For a typical 100,000 square foot building, drilling and excavation is required to facilitate installation of 20 to 25 miles of heat exchanger pipe.

Braun Intertec Geothermal, LLC is providing the thermal and environmental site characterization, ground heat exchanger system design, construction documentation and construction observation and testing services on the BH Whipple Federal Building in Minneapolis. The project represents one of the largest geothermal heat pump systems in Minnesota.

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In the vast majority of larger commercial and institutional projects, insufficient site area is available to support such an installation, unless a vertical configuration is used. This is the primary reason why residential style, open trench horizontal methods are impractical. Solution? Drill, baby, drill.

Vertical bore, closed loop GHX installations are the standard for larger projects. To install the miles of pipe vertically in the ground, hundreds of 4-inch to 6-inch diameter bores are drilled to depths ranging from 100 to 500 feet. These will contain the heat exchanger piping and slurry of clay or cement to establish conductance between the pipe and the earth, and re-establish the natural barriers between grade and among subsurface aquifers. These types of installations are common, and in fact, Braun Intertec Geothermal has been very involved in the design and installation of numerous large institutional and commercial projects.

However, because geology is unpredictable, and because we humans have a checkered past of improperly disposing chemical wastes, turning our sites into pin cushions can be a dicey proposition. GHX installation costs are highly dependent on geologic conditions. If a site is impacted by soil or groundwater contamination, the costs increase due to the special and potentially expensive care required to prevent migration of contaminants to uncontaminated aquifers. What this means, combined with other variables, is the cost to install a GHX system can range between $5 and $35 per square foot. Controlling costs to the lower rather than the upper limit depends on how closely the following rules are observed and applied:

#1 Invest in a comprehensive preplan, prepared by an experienced consultant Nothing is more important to the cost-effective installation of a GSHP system than a comprehensive GHX preplan. Properly prepared early in the schematic design, preplans help to determine the most suitable GHX type, most advantageous use of the geology, realistic site programming, and an accurate estimation of installation costs. Further, they are intended to uncover potential deal killers caused by soil/groundwater contamination, cultural encumbrances, difficult geology, and/or regulatory compliance. Also, a comprehensive preplan dictates the specific scope of work required to properly characterize a site’s thermal, geologic and, if necessary, environmental conditions. Invest in the most experienced consultant available as hundreds of thousands of dollars of first costs may be at stake. #2 Characterize your site thoroughly Change orders due to unforeseen conditions can be devastating to any construction budget. Unless properly characterized, the earth beneath any given site is nothing but an unforeseen condition, and the risk of expensive drilling change orders is very real. For the same reason that multiple geotechnical borings are required to help determine a building’s structural integrity, convergence of data from multiple geothermal test bores is required to effectively address geologic variability. A professional geologist’s observations and logging in accordance with applicable ASTM standards can further decrease the risk of inaccurate characterization and the potential for change orders.

Thermal transfer efficiency can vary dramatically at differing depths and within a given site. Designing GHX systems based on data from a single test may lead to over or under sizing, exposing the owner to the potential for significant unnecessary expense, and/or a lifetime of unsatisfactory performance.

Finally, if contamination is suspected, extra care should be taken during test drilling. Otherwise near-surface contamination could find its way down the boreholes into pristine aquifers. It is important to note that if the geothermal and environmental characterization events are planned properly, both scopes of work can be combined for considerable savings.

#3 Understand the implications of over or under designing the ground heat exchanger Designing a GHX is difficult to do with precision. The GHX must not only perform properly at start up, but also throughout the life of the project. Again, the earth’s variability significantly affects outcome.

Hydrocommissioning is performed after the entire system is completed and connected. Proper preparation of the ground heat exchanger system and heat transfer fluid help to minimize maintenance and provide for proper operation of the HVAC system. The system is controlled by PLC, which allows continuous data collection.

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Our team of GHX designers, engineers and hydrogeologists has designed more than 80 large-scale GHX systems. We have performed more than 250 thermal response tests, and we have managed the construction of more than 40 projects.

Depending on hydrogeologic conditions, the earth’s temperature within the GHX installation area changes due to operation of the GSHP system. The amount of increase/decrease, and therefore, the effect on operational dependability, is unique to each site and project conditions. Currently no viable means is available to quantify ground temperature change over time, and it can only be approximated through the use of software programs. However, because such tools are incapable of accounting for hydrogeologic variability, and their solutions typically don’t correspond, determining proper GHX sizing is anything but a straightforward process. Oversizing the GHX typically results in spending too much money on excessive equipment and installation labor. Undersizing the GHX can lead to unsatisfactory performance because of the system’s inability to provide an adequate entering water temperature, requiring additional demand on the system to heat/cool, and potentially resulting in inefficient overall operation.

Without the benefit of hydrogeologic and GHX design consultation, many mechanical designers often rely on a single program to dictate the owner’s investment and long-term reliability of an HVAC system. This may expose the owner to the potential for risk, which can be measured in tens or even hundreds of thousands of dollars.

A precision GHX design requires experienced interpretation of output from several software programs, combined with thorough measurement and understanding of geologic variability and hydrogeologic thermal recharge. Additionally, boilers and/or cooling devices should be included in the design as a strategy to balance installation and operation costs. Our team of GHX designers, engineers and hydrogeologists has designed more than 80 large-scale GHX systems. We have performed more than 250 thermal response tests, and we have managed the construction of more than 40 projects. #4 Confirm quality of construction Problems associated with improper design or installation of a GHX system may not become evident until long after the contractor receives final payment. Inspection won’t be possible without excavating the parking lot or other expensive landscaping features. Warranties may be difficult to enforce if the root cause of any relative issue cannot be determined.

In the absence of effective construction evaluation, one may be forced to endure contentious meetings, expensive forensic analysis, and associated finger pointing. In the end, the problem will likely

be rectified at great expense to the owner because accountability could not be established. This unfortunate situation would likely be avoided through properly specified and executed construction

accountability between the designer and contractor. This information will be invaluable should problems in performance occur after owner acceptance. In summary, GSHP technology is important to our nation’s initiative to reduce energy consumption and our carbon footprint. It creates comfortable environments and is proven reliable when designed and installed skillfully. However, the first costs to realize these benefits can vary dramatically, and the expense to rectify poor design or installation can be considerable. Project owners and their representatives should understand the risks and take an active role in selecting their consulting, construction and testing teams. For more information about our geothermal consulting services, contact Braun Intertec Geothermal at 320.632.1081.

An example of a directional bore installation using an emerging technology that is among the ground heat exchanger options Braun Intertec Geothermal is capable of performing during design.

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testing and observation.

The process of installing GHX systems is challenging. Observation and testing at key intervals throughout the installation enables determination of contractor conformance and helps to establish clear

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Trust: A Foundation for Lasting SuccessAsk the Professor

By Charles Hubbard, PE, PGchubbard@braunintertec.com

It’s the time of year at Braun Intertec when we look back over last year’s successes and challenges, review our role accountabilities

and competencies, and set goals for the year to come. We are fortunate. We strive to perform our staff reviews within an environment of collaboration, where direct reports can discuss and set goals for their professional and operational growth. We also want to build a sense of trust that breeds motivation and encourages the expression and resolution of, even if it doesn’t eliminate, doubts, concerns and conflicts.

In my opinion, goal-setting is pretty easy. We know that our engineers and scientists need to be technically competent. We know that they have, to varying degrees, both project management and business development responsibilities. We know that to grow they need to consider focusing less on just doing and more on selling, coordinating and/or training. These are all general competencies that reflect the nature of our consulting business.

Building trust is harder. Trust is not built on promises or even the mere delivery of those promises, but instead on the character and actions of the leaders making and delivering on them. Trust comes when the responsibilities given, and the expectations associated with them, are supported appropriately and proportionately by the resources and personnel needed to do the job. Trust comes when those at all levels within an organization, whether acting in a directing role or supporting role, are recognized for their talents and given a stake in their own success as well as that of the firm. Trust comes when leaders who could easily take or retain control instead release it, and then trust – and even advocate for – those to which they have assigned responsibility.

Sounds simple, doesn’t it? So how, then, can it sometimes be so challenging to develop? The answers are many and, in some sense, mysteries. From a purely logistical standpoint, resources and personnel take time and are an investment. From a behavioral standpoint, recognition, empowerment and advocacy require thoughtfulness and discipline, actions that can get lost in the flood of day-to-day activities. But there also must be an element of consideration through which all things flow – this element may be natural or may need to be nurtured and grown. Some leaders can’t help being heroic and controlling not only the outcome of a project or initiative, but also the means to get there. (I’ll fess up – letting go is hard for me too!) Some may feel vulnerable trusting

others with less experience to take the reins. Others have different opinions on strategy or staff utilization and don’t collaborate well with others to discover better ways of doing things. Some have trouble recognizing or accepting their limitations, or the value or skills of those around them. (The leaders I’m most fond of have all preferred shining their light on those they lead, not themselves.) All in all, it requires a great amount of effort and discipline to focus more on building up and supporting those we lead than it does to continue building up and supporting ourselves.

What’s the benefit of building trust? Employees who understand their role, have what they need to do their jobs, feel appreciated for their skills, are included in discussions that impact their success and that of their firm, are empowered to help steer their company’s path and are recognized and advocated for, are happier, more confident and more productive. They are going to be motivated and willing to motivate others. Indeed, they often end up surprising their leaders as well as peers with all they have to offer. The positive energy that arises from such an environment also spills over into the conversations, meetings and projects on which we collaborate with our clients and other consultants. Working collaboratively, supporting and recognizing the talents of those we work with and serve helps our clients and others trust that their success is our primary goal. After all, if you win, we win too, right?

How do we avoid the pitfalls that erode or prevent the establishment of trust? I believe that, in addition to supporting, recognizing, empowering and advocating for others, good leaders need to be accountable and authentic. Leaders must demonstrate their belief in, and hold themselves accountable to, the same values and standards to which they hold others. (Those accountabilities must also be clearly stated.) If the values we declare to be the foundation of our actions and the basis by which we judge the attitudes, decisions and behaviors of our employees are selectively adhered to or violated (and people will know we have violated them, whether we intend for them to know or not), then all trust is lost. See TRUST - Continued on page 5

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Some additional perspective on this, I think, can be gained by defining how we lead. Many of those in leadership positions direct or are called directors. People obviously need to have direction to get where they want to go. But more people than not can probably navigate that path on their own or as a team. I like to think of leaders instead as conductors. In an orchestra, the conductor directs only the tempo and prominence of the many musicians, and guides them through their arrangements to help the orchestra complete its task. He or she cannot play each and every instrument and thus trusts and depends on the talent and experience of each musician to bring the music to life. Conduct also has a nice ring to it in terms of personal character. Merriam-Webster defines conduct as: “The act, manner or process of carrying on; a mode or standard of personal behavior especially as based on moral principles.” Dictionary.com defines conduct as relating to: “Personal behavior; a way of acting; bearing or deportment; the act of conducting; guidance; escort.”

In reviewing my own leadership goals, I will be thinking of ways I can better conduct my direct reports and others within our organization, as well as myself, and better support you, who have been so considerate to read and hopefully enjoy this publication. I think that is an assignment from which we can all benefit.

Good to Hear from You!

Gary Rueter of Fraser Construction Company recently wrote to ask our Deep Foundation expert, Matt Glisson, PE, if low-strain integrity tests could be performed in lieu of static load tests on 20-foot long, 4- to 5-inch diameter micropiles. Here’s what Matt had to say: “Low-strain integrity tests will not tell you how much load a pile can carry like a static load test will, Gary. So, no, low-strain integrity tests cannot replace static load tests. Depending on the loads and equipment availability, we may be able to help you identify a drop weight or pile hammer system that could be used with high-strain dynamic (PDA) testing, however, to help evaluate the compressive and/or uplift capacity of the micropiles.”

We’d love to hear more from our readers. (It will encourage our staff to submit more articles for future issues!) Questions are always worth sharing, as are lessons learned. Please submit your questions or experiences to Charles Hubbard, PE, PG, at chubbard@braunintertec.com.

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Most permanent retaining structures are equipped with one or more drainage components (granular or synthetic vertical drain, drain pipe, etc.) to collect infiltrating surface drainage and subsurface groundwater, and limit the total lateral load the structures need to accommodate. Fluctuating groundwater levels, however, and poorly positioned, poorly performing or overwhelmed drainage components can cause hydrostatic pressures to build up against permanent retaining structures. Many temporary retaining

structures (sheet pile cofferdams, for example) must retain water as well as soil.

Under drained conditions, determining the total lateral load on a retaining structure is easy – you only need to know the moist unit weight of the retained soil and the soil’s earth pressure coefficient. When water is added, however, things get complicated. As shown in the illustration, under undrained or partially drained conditions, the retained soil’s moist unit weight only applies above the water surface; below the water surface, the soil load is determined using the soil’s buoyant unit weight, which is equal to its saturated unit

Hydrostatic Loads Critical to Retaining Structure Design

weight minus the weight of water. (The saturated unit weight is not the same as the moist unit weight. In a saturated soil, the pore spaces are full of water, and the soil is heavier; in a moist or unsaturated soil, the pore spaces are not full of water, and the soil is lighter.) Below the water surface, the hydrostatic load – the load exerted on the wall from the weight of the water alone – must also be determined. The hydrostatic load is based on the unit weight of water and is not factored with an earth pressure coefficient (unlike soil, whose strength supports a portion of its self weight and thus transfers only a portion of its weight horizontally to a structure, water has no strength and thus transfers its full weight horizontally onto the structure).

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By Ben Dzioba, PE, PMPbdzioba@braunintertec.com

As with many transportation construction projects, there are three major concerns for those involved: cost, schedule and quality. One way to address these concerns is by

Three keys to attaining quality on transportation design-build projects

using the increasingly popular design-build construction method. Design-build is a process where the design and construction of a project is delivered through one contract between the owner and the design-build team. While the design-build team may include subcontractors, a major single contract between the owner and the overall project team encourages collaboration and innovation, maintains the continuity of professional oversight, and fosters the creation of a better product.

Design-build also provides a fast delivery method for critical projects overlapping design and construction for the project. Traditional design-bid-build projects require that the entire design be completed prior to the start of construction. Design work is typically performed under a separate contract with the owner. This has advantages and disadvantages. One of the main disadvantages is that when issues arise with the plans, the owner is often responsible for the costs associated with making a correction in the construction. On a design-build project, however, design and construction are under one contract, and it is the design-build team’s responsibility to modify the plans and construction to produce the correct product for the owner.

One of the most well-known design-build projects in Minnesota is the new I-35W Bridge. Braun Intertec provided drilling, geotechnical, environmental and testing services for the project.

Design-build projects are increasingly becoming more popular, especially for large and complex construction projects where time is a concern.

Based on numerous studies, including several by the Federal Highway Administration (FHWA), the design-build construction method completes a project faster and more cost-effectively than traditional building methods, while maintaining an equal or higher level of quality. Specific requirements and measures need to be obtained for design-build projects that often include separate roles to administer the quality program, such as a quality manager, critical activity point manager or a material testing coordinator. Design-build projects are increasingly becoming more popular, especially for large and complex construction projects where time is a concern, such as bridges and transportation projects, sports and health care facilities, office buildings and even complex restoration projects. Braun Intertec has been involved in a number of transportation-related design-build projects, including TH 610, Bridges of Mower County, TH 494, Hastings Bridge, TH 169/494, and Anoka 14, the first county design-build project in Minnesota.

There are many aspects of any given project that impact its overall success and quality. However, experience has shown that there are three keys to producing a high-quality design-build project: having a strong plan, enforcing quality checks and maintaining a degree of flexibility. Each project is unique, with its own set of challenges that require adaptability and flexibility to overcome.

The first key to design-build project success is to have a quality plan tailored to the specific needs of the project. Each site and project is unique and presents unique challenges. One of the great things about design-build is the flexibility and innovation that can occur during the design. Conversely, this may create problems in

maintaining quality as new and creative ideas are implemented. The quality plan should address specific concerns of the contractor’s team and the owner’s team regarding key aspects of

the project, including how to maintain or maximize quality during the design and construction portions of the work. For example, for a current design-build project, because of on-site materials, it was determined that spread footings may be an appropriate foundation for several bridges. This deviation from typical Mn/DOT construction required a quality procedure to be devised for evaluation of the footings during construction.

The quality plan also defines and establishes expectations and responsibility for quality for personnel involved with the project. Once established, it is important that the parties “buy-in” to the plan prior to work. Successful project teams tend to have an attitude of quality that contributes to the project’s overall success. Encouraging team members to take on this attitude may involve special training sessions and the creation of other initiatives designed to increase awareness of the impact each person has on

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the project. Additionally, a quality plan facilitates communication between project designers, contractors and owners, as many times project activities occur simultaneously. As issues and questions arise throughout construction, constant feedback to designers can reduce future questions in the field and produce a higher quality end-product.

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acceptance by the owner. Multiple-level quality review activities can identify problems early in the construction process so they can be addressed in a timely manner, minimizing rework on the project. Rework and patch may ultimately be acceptable solutions but are rarely able to meet the same level of quality that there would have been if the work was done correctly the first time.

By Ron Shaffer, PErshaffer@braunintertec.com

Typically a property is purchased for its location or price. More often than not, however, the real cost of developing a property comes down to the site’s soil and groundwater

Six things to consider before developing your next property

conditions. If you are buying a property in an urban area, many of the “good spots” with suitable soil and groundwater conditions may seem to already be taken. We have seen a tremendous increase in construction on marginal sites and on a large number of problem sites in this area. Here are some things to consider when selecting a property to develop:

1. Primarily, you should look for evidence of marsh soils, uncontrolled fill and rubble, and high groundwater. In established urban areas, the prospective site might contain buried foundations and even contaminated soil and groundwater. Actually, almost any soil or groundwater condition can be found somewhere in the Twin Cities, including expansive soil, landslides, springs and caverns. 2. Look at the land around the prospective property. If the property is near a lake, park, athletic field, golf course or even

rail yards, there is a strong possibility of poor soil. A low site might have water problems. 3. The property’s history may yield insights about its condition. If it was used for farming, the property may be tiled for drainage and the upper three feet of soil may be extensively reworked and soft. A former service station could potentially be contaminated with gasoline. An old gravel pit might contain buried debris. 4. Don’t be deceived by what you see and hear. A level property might be naturally flat, but more likely it contains fill. If the seller says the property was prepared carefully and is “buildable,” ask for documentation. Large trees on a site are not a foolproof indication of good soil conditions, nor does high ground preclude any groundwater problems. 5. Contact an experienced geotechnical consultant and/or environmental professional early on in your property selection process, particularly if you have any reservations about the property. The consultants can quickly check files for existing information on your property. 6. Lastly, ask yourself, “If this property is so good, why is it still available?”

Design-Build offers very unique and positive advantages over more traditional delivery methods. One of the greatest of these, if properly implemented and administered, is the quality program.

The second key to design-build project success is to properly define how quality will be encouraged and enforced throughout the design-build process. There are many pressures put on the design-build team during the project, such as schedule, cost and public involvement. A process should be established for effective implementation of quality to help the project team determine if quality standards are being met and to keep a constant focus on overall quality. Most design and construction activities have quality control (QC), quality assurance (QA) and owner review components. The quality control process utilizes best management practices and fosters the development of procedures that should lead to construction of a product that meets quality standards. The product or project is then checked again by an independent reviewer during the quality assurance phase before

Lastly, with design-build projects, it is essential to maintain some degree of flexibility and adaptability. As with many construction projects, issues with materials or processes can

occur that should be documented, addressed and mitigated to avoid recurrence. Design-build offers very unique and positive advantages over more traditional delivery methods. One of the greatest of these, if properly implemented and administered, is the quality program. There are many other items to consider, but incorporating these three simple principles increases the chances of success of the project.

Ben Dzioba is a registered Project Management Professional (PMP) and a member of the Design-Build Institute of America.

Providing engineering and environmental solutions since 1957

11001 Hampshire Ave. SMinneapolis, MN 55438

Minneapolis 800.279.6100Bismarck 701.255.7180Cedar Rapids 319.365.0961 Duluth 218.624.4967Fargo 800.756.5955Hibbing 800.828.7313La Crosse 800.856.2098Mankato 800.539.0472Milwaukee 262.513.2995Rochester 800.279.1576Saint Cloud 800.828.7344Saint Paul 800.779.1196Geothermal 320.632.1081

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©2011 Braun Intertec Corporation

Questions, Requests and Comments

Charles Hubbard, PE, PG Braun Intertec Corporation 1826 Buerkle Road Saint Paul, MN 55110 Phone: 651.487.7060 chubbard@braunintertec.com

This newsletter contains only general information. For specific applications, please consult your engineering or environmental consultants and legal counsel.

As the flood waters recede, we sincerely hope your communities are unscathed or will experience only minimal damage. If you do find yourself facing flood damage, our building science, industrial hygiene, and environmental and engineering consultants can provide cost-effective, timely solutions, including:

• Damage assessment and mitigation plans• Industrial hygiene and air quality assessments for fungal, bacterial and chemical contaminants• Roadway examinations using nondestructive falling weight deflectometer (FWD) technology• Embankment and slope stability evaluations

For more information about how we can help you restore your community after a flood, contact:

Charles Brenner, PE, LEED AP cbrenner@braunintertec.com952.995.2280

Greg Olson, Senior Industrial Hygienist, CIPgolson@braunintertec.com952.995.2482