SYNTEEN TECHNICAL FABRICS, INC. 3-DIMENSIONAL GEOGRIDS FOR ROAD APPLICATIONS

Transcription

1 SYNTEEN TECHNICAL FABRICS, INC. 3-DIMENSIONAL GEOGRIDS FOR ROAD APPLICATIONS

2 SYNTEEN 3D GEOGRIDS: AN ADVANCED APPROACH TO ROAD STABILIZATION A BETTER GRIP ON SOIL

3 GREATER INTERLOCKING WITH SOIL BETTER WHEEL LOAD DISTRIBUTION

4 EVERY APPLICATION HAS ITS REINFORCEMENT BASIC CONCEPT Geosynthetics are universally recognized as an extremely cost effective method of improving areas with low bearing capacity into areas suitable for a variety of load bearing purposes, particularly pavements. The basic concept is combining geogrid reinforcement with fill soil results in a composite material with improved mechanical performance. This produces cost savings thanks to the use of LESS locally available fill material. The increasing cost of transporting unsuitable soil to a suitable disposal area and the need to supply good quality inert materials from quarries, together with the growing concern for sustainability, have made the use of geosynthetic reinforcement more common. By reinforcing the granular base layers with Synteen biaxial geogrids with a high vertical profile and integral junctions, construction can be can be carried out cost effectively, quickly and with less environmental impact. BENEFITS Reduce aggregate thickness to support wheel loads by up to 45% Possibility to reduce excavation depths by as much as 45% Reduction of the disposal of material from site Substantial reduction in the use of natural resources, aggregates (e.g. quarry stone) Reduction of the frequency and quantity of construction vehicles carrying excavated or imported fill materials A BIT OF THEORY The concept of the plain strain condition in geotechnical engineering is relevant to conditions near strip foundations, embankments, retaining walls. It is appropriate for long structures, wherein the stresses in the long dimension are in equilibrium thereby limiting strain in that direction. This allows analysis of the structure in just two dimensions. This is a very common geometry in civil engineering as it also represents every road, railway structure where loads are distributed through a long channelized geometry, sometimes causing the formation of longitudinal ruts. Traditional flat horizontal layers of geogrid, characterised by an orthotropic (in two orthogonal directions) strength have been successful in reducing the applied bearing load from wheels and rails by increasing confinement of the load bearing soils being reinforced. Since the wheel or rail loads are being applied perpendicular to the orthogonal strengths of the flatly laid geogrids, there are difficulties in mobilizing the full geogrid strengths. By increasing the profile (height) of the orthogonal ribs in a flatly laid geogrid, a superior efficiency is created in mobilizing the geogrid s strength within the soil, and thusly improving lateral confinement. Better lateral confinement provides superior load bearing qualities for the soil being reinforced.

5 HEIGHT MAKES THE 3D DIFFERENCE THE IDEAL GEOGRID Synteen has created the ideal geogrid by adding profile (height) to the orthogonal ribs engaging that third dimension to improve performance. Increasing the rib profile provides a high level of lateral confinement capable of involving a thicker portion of soil, thus creating a true geogrid-soil composite Increasing the rib profile improves stress distribution through the reinforced soil Synteen 3D Geogrids have been developed specifically to provide greater stabilization, exceeding even the excellent performance provided by both Synteen woven and extruded geogrids with integral junctions. Together with the high mechanical characteristics offered by the traditional range of geogrids, Synteen 3D Geogrids are designed to allow high levels of lateral confinement: the result is a revolutionary new family of geogrids. MAXIMIZING INTERLOCK When granular materials are laid and compacted over the reinforcement geogrids, stone particles penetrate the apertures of the grid structure and are eventually locked-in to create a strong and positive interlock along the plane of the geogrid. The interlocking mechanism is essential for the behavior of the geosynthetic reinforcement under consideration. This restraint is the exclusive characteristic of a reinforcement geogrid, providing an effective confinement against any lateral movement of the granular material. This considerably improves the performance of the road surface, providing a high degree of control on settlements and reducing the formation of ruts and gaps. This concept has led the Synteen Research & Development team to manufacture and develop a new innovative range of high profile 3-Dimensional Geogrids with integral junctions that maximize the interlocking within the soil or stone grid matrix, which effectively maximizes the connection between the fill material and the geogrid. Interlocking Lateral Confinement Improved Performance

6 SYNTEEN 3D GEOGRIDS ARE DESIGNED FOR EVERY TYPE OF SOIL When the passive resistance wedges developed by a traditional geogrid are compared with those developed by Synteen 3D Geogrids, the special profiled rib section, forming the vertical backbone of the Synteen 3D geogrid, together with the multilayer structure of the Synteen 3D Geogrids, act on a larger cross section of the aggregate, developing a greater resistance to pullout and more effective confinement of the soil layer. PASSIVE RESISTANCE WEDGES IN CORRESPONDENCE WITH THE RIBS Traditional bi-oriented geogrid STF 3D or 3D XL STF Grid LABORATORY EVALUATION & PERFORMANCE CHARTS USING THE LOADED WHEEL TESTER University of Tennessee - Transport Science Department An extensive test campaign was carried out at the University of Tennessee using specific apparatus to assess the performance of road pavements, specially adapted to allow testing of unbounded granular materials. This apparatus makes it possible to assess the behavior of typical road packages in controlled temperature conditions, in a dry or semi-submerged environment, applying cyclic loads that simulate the transit of tired vehicles with a controlled contact pressure. The tests consist of measuring rut depth at regular intervals after a fixed number of load cycles: in this way it is possible to draw the graphs shown here, indicating the ratio between rut depth and the number of cycles performed. The ratio between rut depth (once the number of cycles for a reinforced section and for an un-reinforced section has been set) is indicated as the Rut Reduction Ratio (R.R.R.) : the ratio between the number of cycles required to reach a given rut depth in the two cases (un-reinforced and reinforced) is known as the Traffic Benefit Ratio (T.B.R.) ; this value indicates the ideal duration of a given road section according to its stratigraphy. 3 rut, 20 kips, 1200 passes, subbase CBR 20% 1.5 rut, 20 kips, 1200 passes, subbase CBR 20% UNREINFORCED SYNTEEN STF 3D UNREINFORCED SYNTEEN STF 3D

7 Synteen 3D Geogrids behavior was tested in collaboration with the Transport Science Department of the University of Tennessee. SYNTEEN TECHNICAL FABRICS - STF 3D gravel SYNTEEN STF 3D Ideal for reinforcing medium-small sized granular soils, having an aperture of 30x30 mm. RUT DEPTH -20% COMPARED TO TRADITIONAL GEOGRIDS -31% COMPARED TO NOT REINFORCED SOIL SYNTEEN TECHNICAL FABRICS - STF 3D XL coarse gravel SYNTEEN STF 3XL These geogrids are characterised by significant dimensions in all three main directions. The particularly thick, concave longitudinal rib section, combined with the 60x55 mm aperture size of the geogrid, allows optimum interaction with coarse granular materials. RUT DEPTH -17% COMPARED TO TRADITIONAL GEOGRIDS -31% COMPARED TO NOT REINFORCED SOIL

8 Synteen Technical Fabrics, Inc. is a privately owned corporation, in business since Synteen grew quickly from servicing the Southeastern United States to servicing all of North America, Mexico and the Caribbean. One of the primary points of pride for the Lancaster, South Carolina based-company is that its products are still made in America. In fact, Synteen maintains its operations in the United States while many other manufacturers have outsourced jobs and even plants to other countries. The company s expert and proficient business operations allow Synteen to produce the highest-quality, most cost-effective geogrids and woven fabric on the market right here in America in a state-of-the-art 40,000 sq. ft. manufacturing facility. US PATENT N. US8,206,060 B2 EUROPEAN PATENT N CHINA PATENT N. ZL ,1 ITALIAN PATENT N RUSSIAN PATENT N Rigorously testing products and constantly striving to provide the highest quality geosynthetics keeps Synteen s skilled weavers and technical experts, who together boast over 75 years of combined experience, very busy. At the same time, Synteen professionals stay on the cutting edge by constantly listening to customer feedback and pioneering the future of geosynthetic products by constantly educating themselves and maintaining an enthusiasm for unprecedented, optimum-performing geosynthetics. Specialist technicians will provide thorough, fast support during planning and execution of the work, helping you to choose the right solutions for your civil engineering and environmental problems. Synteen 1950 W Meeting Street Lancaster, SC Tel jon@synteen.com YOUR NEAREST DISTRIBUTOR: ACF Environmental 2831 Cardwell Road Richmond, VA (800) RThomas@acfenv.com