Keystone SRW test helps FHWA advance earth retention system practice

Keystone Retaining Wall Systems’ KeySystem III was recently evaluated under the Federal Highway Administration’s new Innovations, Developments, Enhancements and Advancements (IDEA) program. Administered by the American Society of Civil Engineers’ Geo-Institute, the technical evaluation serves to improve earth retention systems technology and installation methods.

Austin, Texas-based TRI Environmental subjected Keystone Compac III to sustained load connection testing, results from which contributed to the ASCE Geo-Institute findings for the Federal Highway Administration Innovations, Developments, Enhancements and Advancements program evaluation.

Structural applications for such systems include retaining walls, headwalls/wingwalls, bridge abutments and roadway supports on transportation, commercial, industrial, recreational, public works and residential projects. Approved or recognized by 30 state agencies, KeySystem III is designed to the highest standards and unique requirements of the transportation sector. It consists of dry-cast concrete Keystone Compac III modular units and TenCate Geosynthetics’ Miragrid XT polyester geogrid soil reinforcement. The leading commercial retaining wall product on the market, Keystone Compac features an open core design and pin connection system.

The IDEA assessment updates a 2012 KeySystem II evaluation by the ASCE Highway Innovative Technology Evaluation Center (HITEC). It considered Keystone material, design, construction, performance and quality assurance information against state-of-the-practice criteria outlined in the IDEA protocol. For submittal purposes, the methodology used for KeySystem III follows the current AASHTO LRFD Bridge Design Specifications and FHWA guidelines for Design and Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes.

KeySystem III updates include improved Compac III design features and current information on soil reinforcement. KeySystem III is the first concrete modular block system paired with extensible reinforcement that was previously subject to HITEC, but is now evaluated under IDEA. — Keystone Retaining Wall Systems, Minneapolis, www.keystonewalls.com

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J-J HOOKS BARRIER GAINS DEPARTMENT OF TRANSPORTATION TRACTION

Smith Midland Corp. subsidiary Easi-Set International reports that its Manual for Assessing Safety Hardware (MASH) TL3-tested J-J Hooks temporary precast concrete safety barrier can now be used in 40 states and provinces. As state departments of transportation moved into the Federal Highway Administration-mandated MASH era in January 2020, J-J Hooks was the only tested private design offering a suite of MASH temporary barriers for use on state highways. The connection system is available for free standing installations in 12- and 20-ft. lengths or restrained (bolted and pinned) installations in 12-ft. lengths. MASH-tested 20-ft. barriers contain the original 12-in. high J-Hook, the 12-ft. lengths an 18-in. high J-Hook and deflection limiters.

“With the continued rise in approvals for our MASH barrier designs and future infrastructure spending, we see a strong long-term outlook for increased demand for J-J Hooks sales,” says Easi-Set President Art Miles. J-J Hooks is the most successful, extensively crash tested and DOT-approved private connection design available in the industry, he adds.

Developed and crash tested in the 1990s, the connection system has been in continuous use on state or provincial highways. As the FHWA-mandated testing requirements became more rigorous, the J-J Hooks design kept pace and was enhanced to meet new requirements. From the 1990s forward, the basic J-Hook connection design has remained the same; to date, over 15 million lineal feet of J-J Hooks barrier have been delivered and installed on roadways. Easi-Set credits the system’s highway contractor appeal to the absence of connection hardware; identical ends, allowing it to be turned end-to-end; cast-in connection-alignment guide; high degree of safety, with no hands between sections when setting; and, minimum installation/removal crew requirements.

In the March 2019 NCHRP Transportation Research Board report, “Synthesis of the Performance of Portable Concrete Barrier Systems,” J-J Hooks was rated by barrier users as Highly Preferred or Preferred for its connection design, ease of installation, no loose parts to be inventoried, inspectability, maintainability, and cost effectiveness.