A

PRECAST CONCRETE ELEMENTS

CPI – Concrete Plant International – 6 | 2017 www.cpi-worldwide.com156

With more emphasis on infrastructure improvement andsustainability, precasters need the latest innovation to ex-pand market share and grow their business. One new andinnovative retaining wall and traffic barrier precast systemis Gravix. This new precast system was created to use mod-ern, high quality precast concrete to replace typical cast inplace retaining walls as well as MSE (Mechanically Stabi-lized Earth) structures.

The design makes use of onsite fill versus bringing in selector off site select fill for backfill behind the retaining wall as wellas shorter embedment depth of stems. The Gravix wall unitsvary in stem depth dependent upon the wall height as well assurcharge. A typical wall section has the longest units at thebottom and get shorter as they are stacked vertically. Also atthe top of a wall to follow grade, the casting mold is placedon a tilt table to allow the top of the unit to be cast on a slope.

The sloping top edge of the units allows all of the specialgeometry top units to be precast and customized for eachproject. The angled precasting also provides a leveling unitof various heights and slopes to be used directly below trafficbarrier units to follow roadway grade. The precaster can then

provide a complete retaining wall package to the highwaycontractor. Gravix, providing the larger precast unit and acomplete retaining wall system, allows the highway contractorto use less labor, fewer crews and achieve higher installationrates, saving time and money.

The angled tops also provide a leveling unit of various heightsand slopes to be used directly below Traffic Barrier units tofollow roadway grade. The precaster then can provide a com-plete retaining wall package to the highway contractor.Gravix, providing the larger units and a complete retainingwall system, allows the highway contractor to use less labor,fewer crews and achieve higher installation rates, saving timeand money.

All of the units incorporate a triangular section in the stem thatallows the weight of the backfill to bear on the units below,thus transferring downward pressure, which results in a stabi-lizing effect. In combination, the units create a coherent grav-ity mass designed to resist overturning, sliding and bearingfailure. The design methodology follows the well-acceptedAASHTO guidelines of a conventional Precast Concrete BinWall.

Innovative new retaining wall and traffic barrier precast system

Earth Wall Products, LLC, Marietta, GA 30066, USA

Typical Gravix Retaining Wall with slope above. Gravix Traffic Barrier being placed on Gravix Leveling Unitsto follow roadway grade.

06b-precast_152-195_us_Layout 1 09.11.17 16:17 Seite 156

As internationally acknowledged expert we are providing customized machineryand plant engineering solutions for state-of-the-art precast concrete production.Everything you need for a profitable investment. Made in Germany. Since 1925. www.vollert.de | precast@vollert.de | www.youtube.com/vollertprecast

ALL IN PRECAST PRECAST ALL IN

The global experts for high-end

precast concrete production:

+ expertise from more than 350 plant

projects on all continents

+ solutions for low-energy houses and

earthquake-resistant building systems

+ latest machine technology for every

project requirement

For current reference projects: www.vollert.de

Igor ChukovSenior Sales Manager

AZ CPI N th A i 6 2017 216 135 li h hi i dd 1 26 10 2017 13 22 19

PRECAST CONCRETE ELEMENTS

This same stabilizing effect of the embedded precast stemsworks well to provide overturning and impact resistance fora traffic barrier unit on top of the retaining wall as well. TheGravix traffic barrier unit has been designed to handle aMASH TL-4 impact load, which is a taller and higher impactresistant barrier that more DOT’s are moving toward on future

projects. A conventional traffic barrier on top of a retainingwall would consist of a precast barrier with cast in place mo-ment slab. With the perpendicular stem of the Gravix trafficbarrier acting as a moment slab, capturing the weight of thebackfill, the traffic barrier is able to resist larger impact forces.The adjacent barrier units also are joined together by a

MASH TL-4 Impact Test at Texas Transportation Research Institute Gravix Top/Leveling units being castwith sloping top.

06b-precast_152-195_us_Layout 1 09.11.17 16:17 Seite 157

W

PRECAST CONCRETE ELEMENTS

CPI – Concrete Plant International – 6 | 2017 www.cpi-worldwide.com158

Earth Wall Products, LLC2009 Dorsey Rd, Building G2 Marietta, GA 30066, USAT +1 678 5943451www.earthwallproducts.com

FURTHER INFORMATION

Typical Retaining Wall with slope above cross section Typical Retaining Wall with Traffic Barrier cross section

tongue and groove connection, which allows the units toshare the impact force. The tongue and groove connectionalso helps to maintain alignment and speed up constructionplacement.

However, to get into the highway market with an innovativenew traffic barrier system, extensive design and testing is re-quired. With the design complete, Earth Wall Products had toundergo the process of meeting the MASH TL-4 Impact testwith its Gravix system. A test wall had to be constructed at theTexas Transportation Research Institute (TTI) testing and prov-ing grounds in College Station, Texas, which upon final heightwas eight feet of retaining wall and three feet of traffic barrier.The length of the test section was 150 feet to provide roomfor run out of the crash truck. The MASH TL-4 impact test wassuccessful and upon a thorough review, Gravix received itsLetter of Eligibility from the FHWA. It became the first all pre-cast traffic barrier to pass the MASH TL-4 impact test. Subse-

quently, Gravix has been formally approved to bid projects infifteen state DOT’s with the remaining states having submittalscurrently under review. �

06b-precast_152-195_us_Layout 1 09.11.17 16:17 Seite 158