Dick Gernant, P.E., reviews six project types that are often good candidates for ground improvement and don’t necessarily require expensive solutions.
The geotechnical industry is heavily based in research and development, and our team is constantly looking at ground improvement techniques to improve existing and future projects. But we do come across projects of similar type that often have the need for soil stabilization.
Whether you are planning new construction or an addition to an existing structure, utilizing ground improvement techniques can create effective alternatives to driven piles or over-excavation while supporting the heavier loads of modern structures.
Here are six project types that often benefit from ground improvement for sustainability.
There is a greater focus on renewable energy. Throughout 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 rural sites often have soft, deep soils that are too expensive to dig out.
In our experience, on average, about one in six turbine sites on a large wind farm can have some type of soft or poor soil conditions. Sometimes we’re brought in for two out of 100 sites or for 30 out of 50 sites, and our solutions typically support five feet down to 30 feet below the bottom of the mat. But we have also provided replacement-reinforcing solutions (traditional Geopier GP3® technologies) in limited depth, soft cohesive soils that normally require shallow undercuts of two feet or more.
The beauty of ground improvement includes settlement control, cost savings and efficiency in the construction schedule as well as foundation performance.
Projects with multiple stories often need a ground improvement solution, especially if the project is on a tough site with multiple soil types. We are frequently called in to discuss alternatives to costly foundation solutions for multi-story housing and parking garages.
The use of Rammed Aggregate Pier® displacement technologies, such as Geopier Rampact® or Geopier Impact,® for example, are extremely effective to strengthen loose sands and semi-cohesive soils while still allowing for conventional shallow footing support. These solutions can save the project hundreds of thousands of dollars and still provide long-term differential settlement control.
We work on a lot of school additions and new buildings. Identifying the ground improvement needs for the site of an education facility will help you save time and money during the construction of the project — and help to extend the life of the building. This is important for schools and universities with tight construction deadlines and budgets.
Working early with the design team, we can discuss alternatives to over-excavation or construction of special load transfer platforms, even for building designs with wide spans such as performing arts centers and field houses.
You would probably never guess the level of difficulty presented by large containment structures such as clarifiers or aeration basins. Often, these projects are built over previous settling basins or in areas near waterways. This can present a number of challenges with soil types consisting of organic laden and stratified layers of varying composition materials, groundwater or flooding.
We understand how important the location of city municipal facilities is to the well-being and quality of life for residents. Ground improvement solutions can help these projects move forward, even when less than ideal soil conditions are present.
Cementitious grout can be introduced into Geopier® reinforcing elements to maintain the integrity of the system over time (when organic portions of the soil profile may decompose), or we can include free-draining aggregates to allow for rapid drainage of groundwater when needed.
Your geotechnical engineering consultant should understand a combination of poor soil strategies such as over-excavation and replacement as well as ground improvement techniques like Geopier® soil reinforcing and deep pile foundations. This can help you to identify settlement control solutions for grain bins and other agribusiness storage facilities that will carry heavy loads but can also tolerate higher total settlement magnitudes provided they are relatively uniform across the structure.
Reinforcing solution patterns can be tailored to match the loading conditions so that the more detrimental effects of differential movement are kept low even if overall uniform movements may exceed standard 1-inch values required for buildings and other more sensitive structures.
Grain storage bins are heavily loaded over large areas so that they have a deep influence into the soil profile. Reinforcing solutions only account for the upper depth of the profile while deeper zones need to be addressed by traditional geotechnical analyses. Our solutions offer a variety of options to provide direct contact support while managing settlement, uniform and differential, within acceptable levels.
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.
We have found that ground improvement approaches can strengthen existing soils more economically and faster while being less intrusive on existing traffic flow compared to over-excavation and soil replacement methods. Equipment required for installing reinforcing elements consists of two or three machines which are highly mobile and can accommodate limited working areas.
If the soil conditions of your site are less than ideal, consider ground improvement for a variety of these project types. Time is valuable in the construction world. Working with a firm like Ground Improvement Engineering can save you time, money and headaches throughout your project.
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