Thursday
Jan112018

Leading Thoughts: 1/11/18 Geopier GeoConcrete® Column System replaces traditional Piles

We discussed the Geopier GeoConcrete® Column system with Aaron Gaul, P.E. He designs ground improvement projects in Colorado, Missouri and Oklahoma.

 

 The Geopier GeoConcrete Column system is a “Rigid Inclusion” alternative to conventional deep piling due to its simplicity and cost. This system allows structural engineers to design conventional spread footings over extremely soft and compressible soils. The GeoConcrete columns (GCC) provide high stiffness and support capacity.  They require a compacted granular pad to transfer the loads from the foundations to the GCC elements.

Our installers can build GCC elements very rapidly; this helps with client schedules. Plus, there is no structural tie-in between the footing and the ground improvement element. This eliminates thick, heavily reinforced pile caps.

Quality control is extremely important as would be for any conventional piling approach for soft and weak profiles. During Geopier GCC installation, a full-time Quality Control (QC) representative is present on site to verify and report all QC installation procedures and prepare Daily Geopier Progress Reports.

The Geopier GeoConcrete system is most suitable for soil profiles with compressible soil up to 50 feet below grade with a stiff layer below the compressible material. Depending on the geology, this system could be used anywhere in the United States.

 

The Residences - Oklahoma City, Oklahoma

Project Description:

The Residences is a 334 unit urban mixed-use development with retail, dining, and office space in the film row district of downtown Oklahoma City.  The project consists of six separate structures spanning three city blocks.  Two five-story wood framed apartment buildings make up the largest percentage of housing, along with a five-story concrete and wood frame clubhouse building with a rooftop pool and fitness center.

Parking is handled by multistory cast in place "Podium" parking as well as two precast parking garages over six stories tall.

This project will totally transform the west side of downtown Oklahoma City for years to come, creating an entire new community around the Historic Fred Jones Manufacturing Plant (currently the 21c Hotel).

Subsurface Conditions:

The site had a deep soft soil profile which consisted of  lean clay and sandy lean clay overlying sandy silt, silty sand, and sandy lean clay layers. Bedrock was about 45 feet below grade.

Solution:

Aaron Gaul, P.E. with Ground Improvement Engineering (GIE) designed the Geopier GeoConcrete Column system as an alternative to conventional deep piling parking garage.  Geopier Rammed Aggregate Pier® systems were used to support the lighter structures.

Monday
Nov202017

Project Spotlight: 11/20/17 Geopier Armorpact® is an Effective Method in Organic Soils

We talked to Stephen Weyda, P.E., a senior engineer with Ground Improvement Engineering who works out of Wisconsin and Northwest Illinois. He has been using the Geopier Armorpact® System since 2009.

Geopier Armorpact Installation

In Wisconsin, we have a lot of soft, alluvial organic soils. These organic soils are largely present in undrained areas that are adjacent to waterways and have different grades of organics like a topsoil or peat. When building along a body of water such as a lake, river or wetland, you’re more likely to find these types of soils. These organic soils require a rigid inclusion system, which better supports heavily loaded structures than standard aggregate pier systems. When you’re building an aggregate pier, organic materials degrade and tend to soften around the aggregate. The purpose of the Armorpact shell is to prevent softening of the pier as the result of the degradation of soils outside of the pier. A mandrel pipe is used to fill the shell from the bottom to the top. The Geopier Armorpact System locks a confinement sleeve into place. You now have a system that is robust enough to support the structure. 


Sometimes a competitor will propose a conventional aggregate pier system. We often educate the design team as to the benefits of using a more robust system, especially the geotechnical and structural engineers who understand the soil conditions and need for structural support. Without a robust system in place, the structure could face ongoing settlement throughout its life. This could lead to minor drywall cracking or greater concerns regarding the structural function of the building. We also explain how the upfront cost of the Geopier Armorpact System could be a cost savings down the road for the owner or developer.
 
Recent Geopier Armorpact System Projects

Marling Lumber Redevelopment, Madison, WI
We recently completed a project for the redevelopment of the Marling Lumber on East Washington in Madison, Wisconsin. This large, mixed-use project included multi-family residential units, retail and office space and a parking garage. We used the Geopier Armorpact System for all structures on the site – almost an entire city block. During the bidding process, some of our competitors didn’t address of organic soils. As a bonus over other rigid inclusions, is the flexibility of the Geopier Armorpact System. Let’s say you have an isolated layer at 10-15 feet with footings that drop down to that range. The Geopier Armorpact System allows you to cut the shells to fit the proper elevation. On the other hand, grouting is much more difficult to stop at the correct elevation. This project had footings at multiple levels and we were able to provide a solution to fit the needs of the project.  
Confluence Arts Center (CAC), Eau Claire, WI
We also completed work on the Confluence Arts Center in Eau Claire, Wisconsin. The 130,000 square foot arts center is on the confluence of two rivers in Eau Claire’s downtown. Due to its proximity to the rivers, this structure required a robust system to accommodate the soft, organic soils. This project started in fall 2016 and is slated to open in fall 2018. 
 
If your site has organic soils, you need to focus on what’s important to you as the owner or developer. Are you adverse to risk? What are your expectations for the long-term performance of the structure? The Geopier Armorpact System is a robust, long-term solution that reinforces the soils for more heavily loaded structures and it may just be the system for you.

 

 

Monday
Nov062017

Leading Thoughts: 11/6/17 Six Project Types that Benefit from Ground Improvement

As an engineering firm focused on Geopier® ground improvement, we at Ground Improvement Engineering work on many types of projects, each with its own unique challenges. Whether new construction or a building addition, properly designed ground improvement solutions will help the project construction go smoothly.

Our team is heavily based in research and development, so we are constantly looking at how we can improve. Here are six project types that benefit from ground improvement.

Grain Bins Agricultural yields are booming and with that comes the need for additional storage. Your geotechnical engineering consultant will explore the soils and anticipate how they will react to the loadings. They should also understand poor soil strategies such as over-excavation and replacement as well as ground improvement techniques like Geopier and deep pile foundations. After all, you do not want to be in a position where your site cannot support the grain bin and its contents.

Multi-Story Housing and Retail Construction projects that are multiple stories will often need some sort of ground improvement solution, especially if the project is on a tough site with multiple soil types. Solutions such as the Geopier Densipact® system or Geopier Rammed Aggregate Pier® Systems are used to densify or reinforce the soil so it can support the loads of the multi-story building.

School and University Buildings We work on a lot of school additions and new buildings, including the Integrated Science and Engineering Laboratory Facility (ISELF) at St. Cloud State University. Identifying the ground improvement needs of the site of an education facility will help you save time and money during the construction of the project, and help extend the life of the building. This is important to note as schools and universities can have tight budgets and construction deadlines.

Sports Fields and Stadiums You would probably never guess the level of difficulty presented by the Augustana College Football Stadium site. Click here for a full project overview. We understand how important the placement of a sports field or stadium is to the team and its fans. Ground improvement solutions can help these projects move forward, even when less than ideal soil conditions are present.

Walls and Embankments Depending on the size of your project, soil conditions can vary throughout a site. Before erecting a wall or embankment, you’ll need to know if there is any need for an increase in bearing capacity. From there, a ground improvement solution like Geopier GP3 System can be used (as it was for this project) to limit the need for more expensive solutions. Geopier elements can also perform a dual role as ground improvement and drainage if needed.

Wind Turbines In recent years, a greater focus has been placed on renewable energy. We are currently working on multiple wind farms across the Midwest. Our job often starts by working with the geotechnical engineers on the feasibility of wind energy projects before they go out to bid. Due to their location, these sites often have soft, deep soils that are too expensive to dig out. Most commonly, we will use the Geopier GP3 System and Geopier X1® System for ground improvement because they make the most economic sense. Learn more about our experience working on wind energy projects here.

If the soil conditions of your site are less than ideal, you need to consider ground improvement to help ensure the safety and efficiency of your crew. Time is valuable in the construction world. Working with a firm like Ground Improvement Engineering can save you time, money and headaches throughout the project. 

Wednesday
Oct252017

Leading Thoughts: 10/25/17 Pump Up the Footing Bearing Pressure

Why build a large structure on low bearing pressure footings?  It’s inefficient, costly, and consumes more energy and more of your schedule.  It also brings a feeling of defeatism right away to the project team (okay maybe that is going a bit far!)

We know that Geopier Rammed Aggregate Pier® is many times stiffer than the surrounding soils, especially when the soils are soft.  We have university and peer-reviewed studies and thousands of load tests to prove it.

One of the fringe benefits of this stiffness, besides settlement control, is the potential for high bearing pressures.

Your structural engineer smiles when he sees a high allowable bearing pressure.  And why not?  He can size smaller footings with less reinforcing steel.  The General Contractor can build the footings more quickly and with less cost.  The Owner can spend the savings on things they can actually see!  Like jewelry, fixtures, larger conference table, upgraded golf clubs, etc.

  

Example Project

We recently finished a project in Ames, Iowa with heavy column loads (up to 2,000 kips) over moderately stiff glacial clay till.  Due to settlement control issues the Geotechnical Engineer could not provide a practical design bearing pressure.

Enter Geopier and Ground Improvement Engineering.  We were able to stiffen these soils using the Geopier GP3® system for a bearing pressure of 8,000 pounds per square foot.  That allowed for reasonable footing sizes.  We also controlled settlements to 1-inch. 

We performed modulus load testing to confirm the pier stiffness.  The test imposed a load of 155 kips on a single 30-inch diameter Geopier element; the deflection was less than ½-inch.  Now that is performance!

 

Final Thoughts

You shouldn’t have to settle for a low foundation bearing pressure when your loads are heavy. Give us a call whether you have soft clay, fill, loose sand or peat and organic silt.  We will listen and develop a tailored Geopier solution.

And you can take the savings to the bank. 

Monday
Sep182017

Leading Thoughts: 9/18/17 Why the Geotechnical Engineer Role is critical in Ground Improvement

We sat down with Dick Gernant, P.E. to discuss the benefits of working with a geotechnical engineering firm like Ground Improvement Engineering (GIE). Dick has been a Principal Engineer with GIE since 2003.

Soils are complex. You need someone with practical experience who knows how the soil on your construction site is going to respond under various loading conditions. A geotechnical engineer is the best person to understand the complexities of the soil profiles and how the structural loads are going to affect the soils.

When should the geotechnical engineer be introduced?

Identifying the qualities of the right geotechnical engineering firm starts at your initial point of contact. Many firms provide a sales person as the initial point of contact. This person may not have an engineering background and may hand you off to another point of contact after you’ve hired the firm. Look for a firm like Ground Improvement Engineering, which provides you with one point of contact – always a geotechnical engineer – who will see the project through to completion.

What are the qualities of an experienced geotechnical engineer?

Look for someone with wide range of practical experience working with a variety of soil profiles and projects. Each project has different concerns and constraints. You also want the engineer to look out for best interest of the project including its future uses or implications from an overall, environmental standpoint. You can tell you’re working with an experienced geotechnical engineer when they can anticipate and troubleshoot any complex issues before the crew gets out to the field, including what problems are associated with the soil that they might encounter.

What are the red flags that someone might be working with an engineer who isn’t trained or qualified to do the work?

The biggest red flag is receiving a geotechnical study that is underdeveloped or under scoped. For example, perhaps the program is too short or too widely spaced for the loading. They might also suggest technology or construction processes that aren’t appropriate for the soil type of the project. They need to provide appropriate technology or methods for the soil to respond and behave appropriately.

How can you spot these red flags? Ask them questions about how they would address compaction or excavation on a site, based on the soil profiles. You may also spot these red flags during a project, such as if a soil profile indicates high groundwater and they allow for excavation without appropriate dewatering.

Describe the technology that is available to geotechnical engineers.

There are a number of databases that describe soil conditions with soil survey maps, bedrock maps and soil geology applications. Many of these databases are available through public entities like the county conservation offices. Geotechnical engineers often use this information to plan their investigations to analyze how the soil will respond to planned structure development.

There are various technologies for the exploration of soil strength methods that are more appropriate than others. Your geotechnical engineer should have an understanding of the available exploration methods and what is appropriate for your project. From there, computer modeling allows us to look at the site as a 3D model and determine how the soil is going to respond to the expected load conditions. This improves the construction process, as the appropriate ground improvement solution is applied and makes for a smoother project.

What questions should a client ask before choosing an engineer?

Ask questions how their experience relates to your project. Consider the size of the project footprint and load. Is it a small, single-story building or a large, multi-story construction project? Is it an agriculture structure, such as a large diameter grain bin or fluid tank? Every project requires a familiarity of the implication to the loading onto the soils. If you’re in the transportation industry, you’ll want an engineer with roadway construction or civil construction experience, not a building engineer.

Also ask about their experience working with soil conditions similar to that of your sites. You’re looking for years of practical experience.

Why might someone be hesitant to hire a geotechnical engineer?

Unfortunately, not everyone sees the value of hiring a geotechnical engineer. But keep in mind, the up-front cost of an appropriate soil assessment could save you six figure construction costs or time on schedule.

What are the benefits of hiring a geotechnical engineer?

A geotechnical engineer can anticipate areas of concern, such as loading and stability, as well as help to avert hidden construction issues. Above all else, when you hire a firm like GIE, you will have a geotechnical engineer provide the up-front budget and design analyses, proposals, the ground improvement design and follow the project through completion.

Learn about our geotechnical experience by checking out our case histories