Producer/Manufacturer: TenCate Geosynthetics
Primary Use: Main Fabric
Engineer Company 1
Universal Engineering Science
Brasfield & Gorrie
Please describe the project specifications
Construction of a new one-story hospital and four-story patient tower was planned for Fountain Medical in St. Augustine. Prior to construction, a geotechnical investigation was completed and found the presence of very weak organic soils where a temporary construction access road was to be built. Borings performed by Universal Engineering Sciences showed that these soils were located at the surface and extended to approximately five feet below grade. The contractor needed a cost-effective solution to stabilize the access road.
What is unique or complex about the project?
The contractor needed a cost-effective solution to stabilize the access road, which would be open for a minimum of six months and would be subject to daily loading from heavy construction vehicles. Mirafi® RS580i was selected to stabilize the access road because it is designed to increase sustainability to roadway structures in extremely soft subgrades. The design included a 14 inch thick cross-section that was designed to have zero maintenance during the roadway’s lifespan. A thinner cross-section was considered, but would have required maintenance during its service life. The thicker design was selected because there would be no loss of time during any necessary maintenance periods.
The geotechnical engineer on the project recommended total removal of the organic soils before construction of the roadway or the use of a stabilization geosynthetic. Complete removal would have been costly and time consuming because the section of the property where the organic soils were located typically remained under a few inches of water. Considering that the access road would only used during construction, the contractor wanted a more cost-effective solution.
To prepare for the placement of the RS580i, the contractor removed large branches and stumps from the anticipated roadway area. Once the site was cleared of debris, the geotextile was rolled out along the path of the roadway. Adjacent rolls of geotextile were overlapped three feet per the installation instruction provided by our company. The high waterflow rate of the RS580i allowed the standing water to flow freely through the material while containing the organics from contaminating the rock placed on top the high strength geotextile. The rock was placed in a single lift and then pushed into place. Equipment was used to compact it per the design. The placement of the geotextile and construction of the roadway were completed in a day.
The roadway was used for more than one year and was subjected to daily traffic from construction loads during this time. During the life of the access road, no ruts developed and no re-grading or maintenance was required. The success of the construction entrance resulted in an additional contract for the inclusion of RS580i in the paved section of the hospital entrance.
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