(Photo, Left - Mirafi 500X, Mirafi 600X Geotextile Fabric)
Mirafi 500X – Lakeland, Florida
The parking lot for a retail area in Lakeland, Florida was almost completely composed of sandy soil. This area also had phosphate sludge in the soil that needed to be removed and replaced. In order to do this, they needed to employ the use of geosynthetics which are synthetic products used to stabilize soil. The chose a separator fabric that is a very strong polypropylene and bi-axial geogrid. This area was designed for a parking lot for the retail facilities. In order to reduce ground settlement, reduce costs for construction, and make the system long lasting, geosynthetics were chosen.
The engineering firm originally suggested a different bi-axial geogrid but due to the wet conditions, it was determined that a strong geotextile that would separate, filter, and reinforce would be needed. Mirafi® HP570 was chosen along with a lightweight woven separator fabric Mirafi® 500X and bi-axial geogrid Mirafi® BXG12. The designers were instrumental in getting the Mirafi products approved by the engineer. Geotextiles and geogrid would reduce the undercutting in the parking lot and reduce the amount of material needed to remove other materials from the site. Using Mirafi® products would allow work to continue and save on costs and time.
The construction started in the summer of 2005 and completed in the summer of 20017. The installation of the geotextile was subcontracted to a contractor who fastened the material together for a better coverage and allowed extending over the phosphate sludge.
Mirafi® geosynthetics saved both time a money and gave a great deal more flexibility to the contractor and designer. The products were available for installation whenever the contractor needed them. The geosynthetic system offered a long lasting, more staple formation level for the parking lot for a very long time to come.
For additional information, and CAD details please see the TenCate website.
Mirafi 500X – Minneapolis, MN
The backyard of a a high-end home had been built on an unusable slope that led to a fairway on the golf course. The objective was to create a living and hardscape area for outdoor entertainment with the limited space that was available. At the same time, maintaining a green buffer from the fairway.
The Designing Process:
The owner realized the backyard required a drastic design change after the house was built. He wanted something to separate the yard from the fairway and have a hardscape for entertaining. Keystone Block and Miragrid® Geogrids were specifically designed to separate the grade changes to the 2 properties. This product was approved by both the owner and the golf course association. After the retaining walls were in place and the grade was positioned, Mirafi® 500X was implemented to separate the clay sub-base from the 3/4” limestone.
Excavation for the modular block wall was performed along the property line. The soil in the parking lot was a heavy clay so placing 500X over this area was essential along with placing a 3/4" limestone along the base footing. The standards of Keystone were used and 3 courses were used for a footing. Mirafi® 5XT was implemented to reinforce the poor soil and to create a staple foundation for the hardscape surface. All base work used 100% crushed limestone and 500X. A fine wash granular sand was then used to set the hardscape surface.
The owner was extremely pleased with the finished project. Due the extensive knowledge of the engineer and contractor allowed them to develop a useable backyard for entertaining. They designed the landscaping structures using geosynthetics and concrete products. In turn, the owner received a useable backyard which originally had a steep slope. This project was performed in 2001 and to date, the construction still performs like new.
Mirafi 500X – Mirafi 600X - St. Louis
The construction company created the Metrolink light rail system for the St. Louis area. The system covered 35 miles of track and cost $339 million for this St. Clair County development. The project would require 42 retaining walls adding up to up 169,000 feet.
The Designing Process:
Designing the walls needed global stability calculations, analysis of the foundation, seismic calculations, AASHTO design procedures, and area fees. Most of the walls were sitting on poor soil and in some cases, the foundation stabilization treatment extended to 15 feet below the base. It was deemed that many of the walls would settle a considerable amount during and after construction due to the new fill weight. The MSE wall system is good for settlement but posed a problem at various locations with hard surfaces. Box culverts would have various settlements that could destroy the blocks.
A good design would have to implemented to allow for this settlement without stalling the construction or causing stress to the blocks. It was decided to saw-cut a settlement joint at the edged of the structure. Even though blocks moved differently, from a distance it would not be noticeable.
The foundation was extremely soft and required various improvements in order to support the retaining walls. The options available were to excavate into the water table or use a strong fabric to give load support. Using one layer of Mirafi® 500X and a layer of HP Series would offer the strength needed to create a safe design. Many of the retaining walls in this area were sitting on a slope and very close to the creek which was made up of very soft soil. The combination of the base of the wall along with this soft soil and fee loading required a review of several options to offer a safe structure. By increasing the Mirafi® geogrid length and improving the soil would offer the most cost-efficient solution for the contractor.
Using innovative ideas saved on cost by optimizing the geogrid's strength, the number of layers required in the designing, looking at various foundation options, and using very strong geotextiles. Mirafi® 500X and 600X have extended the pavement life in the parking lots and Mirafi® HP fabrics stabilized the project.