“All the good sites are gone.” Have you heard that one before? I think we all have. Well, there are still a lot of good sites remaining; they just take a little more creativity to develop. At least that’s what I like to think.
One issue with many development sites is the presence of soft soils. These sites typically require fill to raise them out of flood plains or up to surrounding grades. This amount of fill, combined with building loads, can often lead to significant settlement. In the past, these sites may have been passed over for a better one, but today many of them are considered prime locations.
In many cases, pre-loading and/or post-grading waiting periods are recommended to allow the natural soils to settle, therefore reducing post-construction settlement. The waiting periods for some sites can be measured in weeks, months, or sometimes years. Maybe you don’t have time to pre-load, or maybe there is an existing structure on site that wasn’t designed to handle the settlement of adjacent soils or the added lateral load of new fill.
Whatever the case, lightweight fill may be an option. By reducing the weight of the fill material, you can significantly reduce the load applied to the natural soils and help limit settlement.
One form of lightweight fill is EPS (Expanded Polystyrene), also commonly referred to as geofoam. Geofoam is extremely lightweight, weighing as little as 5 percent of typical soils. It can be designed and manufactured based on project requirements and applicable ASTM standards, and it can be installed during inclement weather.
Geofoam is delivered in various block sizes, can be easily cut to required dimensions in the field, and is extremely efficient to install. These characteristics can make it a useful option for projects involving soft or compressible soils, grade changes, settlement concerns, or construction where reducing loads on underlying soils is important.
Other forms of lightweight fill that are commonly used include foamed concrete, waste material from local industrial and process facilities, and wood chips or fiber. Each of these materials has unique characteristics and may also be applicable depending on project conditions.
If you have questions about lightweight fill, geofoam, soft soil settlement, or ground improvement options, or have a project you would like to discuss, contact SCI Engineering to learn more.
