Fabric name: Mirafi
Fabric producer: TenCate Geosynthetics
Fabric supplier: TenCate Geosynthetics
Engineer: Southern California Geotechnical (SCG) and RBF Consulting
Design: RBF Consulting
Fabrication: TenCate Geosynthetics
Subcontractor: Oltmans Construction Company
Project manager: Sares Regis Group
Installation: Oltmans Construction Company
Location: 16300,16388, 16397 Fern Avenue and 16380 Euclid Avenue, Chino, California
Please describe the project specifications.
A. Geotextile: a. The geotextile shall be woven from super high-tenacity polypropylene yarns with a weave pattern to maximize strength, water flow, soil interaction and soil retention. The yarns shall be from high-tenacity long-chain synthetic polymers composed of at least 95 percent by weight of polyolefins or polyesters. They shall form a stable network such that the filaments or yarns retain their dimensional stability relative to each other, including selvages. b. The geotextile shall meet the requirements of Table 1. All numeric values in Table 1 except AOS represent MARV in the specified direction. Values for AOS represent maximum average roll values. c. All geotextile products shall have a separation factor of 0.9 or higher per ASTM D422, Modified. d. Approved geotextiles are as follows: Mirafi® RS380i
What was the purpose of this project? What did the client request?
The purpose of the project was to develop four (4) new commercial/industrial buildings ranging from 89,100± ft2 to 789,084± ft2 in size and accompanying truck loading docks and parking lots using a durable high strength geotextile in conjunction with onsite recycled concrete debris.
What is unique or complex about the project?
Portions of the proposed building sites were located over former detention ponds and compressible soils that were very soft and saturated. These areas were not suitable for placement of new engineered fill that could support the building foundations that required up to 30’ of fill. The building sites were also littered with concrete debris that needed to be taken to a landfill. Rather than haul this debris away, it was crushed down to 8” particle sizes and used in conjunction with TenCate Mirafi® RS380i, a permeable high modulus geotextile, to create a 2’ thick stable platform for placement of engineered fill below the structures. Mirafi RS380i was first placed over the existing wet soils, followed by a layer of crushed concrete to create a separation layer (without the separation function provided by Mirafi RS380i, the crushed concrete would disappear into the muddy subgrade and provide no stabilization benefit). The high permeability of Mirafi RS380i allows water to pass through it into the clean free draining concrete layer above (without a free draining layer provided by Mirafi RS380i – a wet subgrade behaves in a fluid manner like a waterbed). The high tensile modulus of Mirafi RS380i combined with the crushed concrete increased bearing capacity, allowing construction equipment to place fill over these unstable areas (construction equipment will sink into an untreated saturated soft subgrade without first placing a high modulus geotextile).
What were the results of the project?
The installation of the high modulus geotextile in conjunction with the recycled concrete debris had the added benefit of saving valuable landfill space and carbon emissions that would have resulted from removing old concrete debris and hauling in new stone to stabilize the underlying soft subgrade. The stabilization layer that used the recycled concrete debris with the TenCate Mirafi RS380i was noted to be firm and unyielding beneath the weight of the huge CAT 837 scrapers (used to place and compact the new engineered fills) and other grading equipment. The fill soils were successfully compacted to project specifications, which pleased the geotechnical engineer. The use of the TenCate Mirafi RS380i geotextile allowed the contractor to use recycled debris and treat the very poor subgrade conditions to create a very stable building platform. The TenCate Mirafi RS380i has very high durability and it remained undamaged during the placement and compaction by heavy equipment of the highly angular 2-8 inch crushed concrete over it. The result is a completed firm stabilized platform for construction of the 4 commercial buildings & surrounding parking lots & loading docks.
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