Applications, Design & Construction Considerations for EPS Geofoam

Originally posted on CE News online in Progressive Engineering

Geofoam: A lightweight fill alternative

Pacific Bridge

To widen the Pacific Street Bridge over I-680 in Omaha, Neb., Hawkins Construction excavated the soil between the existing abutment wall using EPS geofoam as lightweight backfill for the bridge approach.

Geofoam is a rigid, engineered, lightweight fill material typically made of expanded polystyrene (EPS). For fills, a key advantage of EPS geofoam is its low weight — approximately 1 to 2 percent the weight of soil. Typical densities for EPS fill are between 0.7 and 2.85 pounds per cubic foot, therefore maintaining a predictable compressive strength that is suitable for many structural applications (see “Geofoam physical properties”).

Today, geofoam is fully recognized and accepted as a lightweight fill alternative and has seen increased use in commercial and residential applications. Since the first installation of geofoam in 1965 (see “A short history of geofoam”), numerous projects around the world that have relied on the material to solve construction problems.

Given EPS geofoam’s low weight, strength, and ease of use, more project teams are using it to solve regular construction challenges in five basic applications.  Read the full article featured on CE NEWS as our Geofoam Specialist, Nico, discusses:

  • The five basic applications and specific project examples:  1.)  Lateral load reductions on structures  2.)  Soft soil remediation  3.)  Slope stabilization  4.)  Lateral and dead load reductions over buried utilities  5.)  Lightweight structural void fill.
  • Geofoam physical properties
  • Short history of geofoam
  • Construction considerations
  • Cost saving advantages

INSULFOAM GEOFOAM QUESTIONS

Nico Sutmoller, Insulfoam Geofoam Specialist

Nico Sutmoller, Insulfoam Geofoam Specialist

Contact Nico Sutmoller, Below-Grade & Geofoam Specialist

nico.sutmoller@insulfoam.com

Ask Nico to Connect on LinkedIn  |  Follow Insulfoam on LinkedIn

Read more on Insulfoam.com

Lightweight Geofoam Fill Supports Highway Construction

Originally posted on SitePrep online, March 2014

Working in the soft soils of Trinidad, the contractor specified EPS geofoam to reduce the load applied to the pile cap under the existing pier on this freeway interchange project.

Working in the soft soils of Trinidad, the contractor specified EPS geofoam to reduce the load applied to the pile cap under the existing pier on this freeway interchange project.

Although greenfield site preparation can involve a host of geotechnical challenges, in urban areas the need to work around existing infrastructure presents its own costly and complex design problems.

A new freeway interchange at Valsayn on the Caribbean island of Trinidad provides a clear example of the potential difficulties.  Traffic growth in the island nation required the development of a new grade-separated interchange between two primary highways – the Churchill-Roosevelt Highway (CRH) and the Uriah Butler Highway (UBH).

One challenge the project team faced was that the north and southbound lanes of the UBH needed to pass adjacent to (and on both sides of) a support column for an existing flyover ramp.  The new lanes required pavement of 9.8 to 10.5 ft. of embankment fill on top of the pier’s pile cap on very soft soils.  A concrete shaft of seismic activity.  The concrete shaft also keeps the pier in depended for the the new fill.

Designing infrastructure to mitigate earthquake damage is crucial in Trinidad, which lies near the boundary of two tectonic plates.  The island has been impacted by five earthquakes greater than magnitude 7.0 since the 1700s, including a 7.3 quake in 2007.

To reduce the load applied to the pile cap under the existing pier, and to avoid any modification of the pier’s seismic behavior, contractor Vinci Construction Grands Projects specified InsulFoam GF expanded polystyrene (EPS) geofoam as a lightweight fill.  Goefoam offers high compressive strength and predictability, yet weighs up to 100 times less than traditional soil fills depending on the EPS density selected.

EPS geofoam fill provided a cost-effective alternative to building a concrete slab founded on piles to support the load from the road and transfer it away from the pier pile cap.

EPS geofoam fill provided a cost-effective alternative to building a concrete slab founded on piles to support the load from the road and transfer it away from the pier pile cap.

Vinci Construction Grands Projets crews placed 2,100 cu. yds. of EPS22 geofoam fill in an 80 by 89 ft. area surrounding the pier in only three-and-a-half days. “Because of the ease and speed of installation, using geofoam allowed us to build this fill two times faster than a regular sand fill, especially in Trinidad where heavy rains can interrupt back filling activities for days,” says Cecile Huillard, construction engineer with Vinci Construction Grands Projets.

Huillard notes the use of EPS geofoam fill provided a cost-effective and simple alternative to building a concrete slab founded on piles to support the load from the road and transfer it away from the pier pile cap. No heavy equipment was needed for the fill placement, as crews were able to install the geofoam blocks by hand. Additionally, the geofoam resulted in lower and smoother post-construction differential settlements of the roadway in both the transversal and longitudinal directions. The use of geofoam also eliminated the need for additional geotechnical investigation for potential additional piles.

Using EPS geofoam as a lightweight fill reduces labor and material costs without the need for over-excavation.

Using EPS geofoam as a lightweight fill reduces labor and material costs without the need for over-excavation.

EPS geofoam does not typically require surcharging, preloading or the staging often necessary with other fills. It resists moisture, freeze-thaw damage, insects, mold and decomposition. The product is inert, does not emit undesirable gases or leachates, and is reusable or recyclable. EPS geofoam is available in multiple strengths suitable for a wide range of engineered applications. The EPS22 geofoam specified in the CRH/UBH interchange project has a compressive resistance of 1,051 psf at 1-percent deformation.

In addition to soft soil remediation and reducing vertical loads on existing infrastructure and utilities, engineers have used EPS geofoam to solve a range of other geotechnical challenges, as outlined in the adjacent article, Applications for Lightweight Geofoam Fill.

Applications for Lightweight Geofoam Fill

Given EPS geofoam’s low weight, strength and ease of use, more project teams are using it to solve regular construction challenges in five basic applications:

1. Eliminate or reduce lateral loads on structures.

2.     Create a zero loading factor for soft soil remediation.

3.     Lighten the driving block of a landslide for slope stabilization.

4.     Reduce lateral and dead loads over existing or newly buried utilities.

5.     Use as lightweight structural void-fill for numerous concrete and landscaping applications.

STRUCTURE LOAD REDUCTION

EPS geofoam significantly reduces lateral loads on retaining walls and building foundations. The material has an extremely low Poisson’s ratio (.05) and high coefficient of friction (.6), which helps enable placement of blocks in a way that replaces the sliding soil wedge above the angle of repose. By replacing the active wedge with EPS geofoam, which can be completely freestanding and self-supporting, project teams can save up to 75 percent of total project costs compared to traditional concrete walls designed to retain soil.

Using EPS geofoam also reduces labor and material costs without the need for over-excavation, and requires much less robust forming, reduced structural steel and concrete wall thickness, and fewer footings. The material can also reduce or eliminate the need for geo-grids and/or mechanical tiebacks. Project teams are able to construct a retaining wall with EPS geofoam paired with a lower-cost fascia (which acts more like a fence).

Another key advantage of using the material in retaining wall applications is the allowance for taller walls in narrower rights-of-way. This reduces time and cost spent on property acquisition, as well as minimizes lane closures and encroachment into wetlands or neighboring properties.

SOFT SOIL REMEDIATION

Ground with soft soils or soft clay makes construction difficult. These soft surfaces are notoriously poor foundations for many projects, and can require extensive remediation.

Instead of choosing costly (surcharging) and time-consuming remediation of soft soils, projects of all sizes can install EPS geofoam, which provides high load-support while maintaining a low weight.

SLOPE STABILIZATION

EPS geofoam’s low weight makes it an excellent option for stabilizing steep slopes, without the need to change the final slope geometry. As the material is much lighter than other fills, it greatly reduces the weight of a slope’s driving block and lowers the risk of costly and dangerous slope failures.

Additionally, since slope stabilization generally happens on steep and uneven terrain, using EPS geofoam simplifies construction, because crews can move and place it without heavy earthmoving and compaction equipment, thus greatly speeding up the construction schedule.

UTILITIES LOAD REDUCTION

Throughout the world, existing buried utilities create challenges for new construction. Notably, utilities frequently are not designed to have additional loads placed upon them. So, utilities either have to be moved or upgraded at high expense.

Instead, geofoam can be an ideal option to reduce dead and lateral loads on underground pipes, culverts and tunnels, while at the same time providing high thermal insulation values that protect against temperature fluctuations.

Another advantage is geofoam can protect utilities during seismic activity by reducing in-situ vertical/lateral stresses.

STRUCTURAL VOID FILL

Given its low weight, EPS geofoam is also well suited as a structural void fill in concrete forming operations. Crews can easily fabricate virtually any shape or slope, and the material eliminates separate concrete pours for vertical wall sections and topping slabs.

Applications include bridge column formwork, stadium seating in auditoriums and sports arenas, stairways, podiums, loading docks and rooftop pool decks. EPS geofoam can be manufactured into custom-cut blocks in various shapes and sizes to enable contractors to quickly build up these and other similar features.

Article featured on SitePrep 

“Because of the ease and speed of installation, using geofoam allowed us to build this fill two times faster than a regular sand fill, especially in Trinidad where heavy rains can interrupt back filling activities for days.”  - Cecile Huillard, Construction Engineer, Vinci Construction Grands Projects

INSULFOAM GEOFOAM QUESTIONS?

Nico Sutmoller, Insulfoam Geofoam Specialist

Nico Sutmoller, Insulfoam Geofoam Specialist

Contact Nico Sutmoller, Below-Grade & Geofoam Specialist

nico.sutmoller@insulfoam.com

Ask Nico to Connect on LinkedIn  |  Follow Insulfoam on LinkedIn

Read more on Insulfoam.com

Expanded Polystyrene (EPS) Geofoam Vs. Traditional Fill

Public Works_2013 cover photo

2013 Public Works Magazine

Developed in the 1960′s as an engineered geotechnical material, expanded polystyrene (EPS) geofoam performs well in numerous applications and was designated by the Federal Highway Administration (FHWA) as a “priority, market-ready technology” in 2006.  As outlined in the spring 2013 Public Works magazine annual reference “Manual”, geofoam is 100% recyclable and non-toxic and it’s lightweight fill is used to reduce vertical stresses beneath embankments and lateral stresses on retaining walls, abutments, or foundations.  

Read more in the Public Works magazine:

  • geofoam defining properties
  • how to choose a geofoam supplier
  • per-cubic-yard costs of various fills
  • public works applications
  • key benefits
  • EPS goefoam cost vs. other fills

Read more on Geofoam:

QUESTIONS?

Nico Sutmoller, Insulfoam Geofoam Specialist

Nico Sutmoller, Insulfoam Geofoam Specialist

Contact Nico Sutmoller, Geofoam Specialist

nico.sutmoller@insulfoam.com

Connect with Nico on LinkedIn

Reducing Loads for Soft Soil Remediation

Geofoam Installation, Phillis Wheatley Elementary

Geofoam Installation, Phillis Wheatley Elementary

Built in 1954, Phillis Wheatley Elementary School in New Orleans has been closed since Hurricane Katrina flooded the area and was left in a state of disrepair.  The 57 year old school was originally built as a segregated school for African Americans and was decided to be demolished and rebuilt after much opposition, debate and protests.  Demolition was completed in 2011 and the new school is in construction.

InsulFoam Geofoam was chosen as a lightweight fill to raise the main slab from its original elevation and lighten up loads on the subsoils.  Geofoam’s lighweight nature takes up space without adding stress to the underlying soil or structure.  There are many benefits of using InsulFoam Geofoam for reducing loads for soft soil remediation such as:  INCREASES speed of installation and productivity, DECREASES rights-of-way concerns, traffic closures, heavy equipment costs, soil removal costs, borrow-fill placement, ELIMINATES surcharging time/cost, soil settlement, and secondary compaction.

InsulFoam Geofoam is also environmentally friendly and 100% recyclable, containing no HCFCs or formaldehyde. With superior stability and long-term R-value, InsulFoam Geofoam resists insects, mold, decomposition and severe weather conditions, including freeze-thaw cycles and moisture penetration.

CLICK HERE to see Phillis Wheatley Elementary GEOFOAM construction installation photos

Phillis Wheatley Elementary, Geofoam Installation

Geofoam Installation, Phillis Wheatley Elementary

Phillis Wheatley Elementary

Geofoam questions or need to discuss your project?

Contact Nico Sutmoller, Geofoam Specialist

nico.sutmoller@insulfoam.com

Connect with Nico on LinkedIn

Local Governments use Geofoam to Overcome Common Geotechnical Challenges

US50 near Montrose, CO

Over 100 times lighter than soil, EPS Geofoam continues to prove to be successful in high-volume fill and soil stabilization projects such as roads, bridges, levees and buildings.  Local city and county agencies have used Insulfoam Geofoam in many projects to simplify construction and reduce costs for public works projects.  Geofoam has many features and benefits to help overcome common geotechnical challenges:  high load-bearing capacities, does not decompose, decay, or produce undesirable gases or leachates, fully recyclable, durable and does not require maintenance under normal conditions throughout service life, unaffected by freeze-thaw cycles, moisture, and road salts.

Read more on how the following Geofoam applications were used from project to project in Government Engineering Journal’s article, Geofoam:  A Primer.

Slope Stabilization:

  • US50 near Montrose, CO
  • Highway 12 near White Pass in WA State
  • US101 in Northern CA

Lightweight Void Fill:

  • Fairfeld-Suisun Water Treatment Plant channel walls in Solano County, CA
  • Idaho Transportation Department

Lateral load reduction on Retaining Structures:

  • Pacific Street Bridge Widening in Omaha NE

Soft Soil Remediation:

  • Alaskan Way Viaduct replacement in Seattle, WA
  • I-80/I-65 interchange widening in Gary, IN
  • North Creek Levee raising in Bothell, WA