Innovations and Research in Roadside and Median BarriersRonald K. Faller, Ph.D., P.E.Assistant Director & Research Assistant ProfessorMidwest Roadside Safety Facility (MwRSF)Nebraska Transportation CenterUniversity of Nebraska-LincolnLincoln, Nebraska2012 MINK Local Roads ConferenceStoney Creek InnSt. Joseph, MissouriSeptember 26-27, 2012
Midwest Roadside Safety Facility Introduction• 1.3 million traffic deaths & 50 million injuries per year around world – significant societal impact• 34,000 traffic deaths & 2.2 million injuries in 2009 in U.S. (NHTSA)• ⅓ of fatal crashes w/ fixed objects• Barrier innovations & ongoing research Midwest Guardrail System (MGS) long-span over culverts, low-cost bridge rail, side-mounted attachment to culverts, MSE wall applications, non-blocked steel post, rectangular wood post, minimum length Stiffened Portable Concrete Barriers (PCBs) 2
Midwest Roadside Safety Facility Midwest Guardrail System (MGS)• Sponsored by Midwest States Pooled Fund Program• 50+yrs use strong-post W-beam guardrails• Early W-beam systems designed for full-size sedans & small cars• Varied performance for 27” W-beam guardrail• Metrication to 27¾” w/ many acceptable variations• Improve performance for high c.g. vehicles 3
Test No. 4798-71,963 kg/95.3 km/hr/24.0 deg686 mm (27 in.) HeightVehicle Rollover (Failure)Dynamic Deflection = 28.1 in. 4
Test No. 471470-27 Midwest Roadside Safety Facility2,075 kg/101.4 km/hr/26.1 deg686 mm (27 in.) HeightVehicle Rollover (Failure)Dynamic Deflection = 35.8 in. 5
Midwest Roadside Safety FacilityMGS Bridge Railing• Sponsored by Midwest States Pooled Fund Program• Research Objectives TL-3 guidelines of MASH low-cost bridge rail for rural highways & county roads available for use on bridges, including longer than 25 ft minimize deck width easy post replacement 16
Midwest Roadside Safety Facility Base Configuration• Half-post spacing (3 ft - 1½ in.)• S3x5.7 posts w/o blockouts 17
Midwest Roadside Safety FacilitySide-Mounted Bridge Deck Connection• 4”x4”x⅜” tube w/ top plate & L bracket• 1” dia. A325 hex bolt• Special deck reinforcement 18
Test No. MGSBR-15,174-lb Dodge QuadCab61.9 mph & 24.9 degreesD.D. = 49 in. 19
Midwest Roadside Safety FacilityMGS Bridge Rail Adapted to Box Culverts• Sponsored by Midwest States Pooled Fund Program• Research Objectives TL-3 guidelines of MASH low-cost guardrail for rural highways & county roads available for use on culverts, including longer than 25 ft 24
Midwest Roadside Safety Facility Blocked MGS: Wood vs. Steel Post Pickup Truck Small Car Evaluation Criteria MGS MGS Wood MGS MGS Wood Steel Post Post Steel Post PostOIV: Longitudinal (ft/s) 15.3 13.3 14.8 15.7OIV: Lateral (ft/s) 15.6 14.7 17.1 20.9ORA: Longitudinal (g’s) 8.2 8.1 16.1 13.0ORA: Lateral (g’s) 6.9 8.5 8.4 9.3Dynamic Deflection (in.) 43.9 40.0 28.6 22.2IS (kip-ft) 122.3 115.5 55.0 56.4
Midwest Roadside Safety Facility Minimum Effective Length of MGS• Sponsored by Wisconsin Department of Transportation• Research Objectives minimum system length of MGS barrier deflections for various system lengths TL-3 guidelines of MASH• 75-ft minimum length for full-scale crash testing historical length for crash testing – 175 ft prior recommendations for minimum length, excluding bridge approach sections – 175 ft
Test No. MGSMIN-12270P Pickup Truck62.9 mph & 25.0 degD.D. = 43 in.
Midwest Roadside Safety FacilityLateral Stiffening of PCBs w/o Anchorage• Sponsored by Wisconsin Department of Transportation• Research Objectives minimize barrier deflections without anchorage to bridge decks utilize MwRSF’s 12.5-ft long F-shape PCB TL-3 guidelines of MASH
Free-Standing F-Shape PCB MASH Test No. 2214TB-2 2270P Pickup Truck 62.0 mph & 25.4 deg D.D. ≈ 80 in.