Testing and Evaluation of MASH TL-3 Transition Between Guardrail and Portable Concrete Barriers

Three full-scale vehicle crash tests were conducted according to the Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) safety performance criteria on a transition between the Midwest Guardrail System (MGS) and a portable concrete barrier (PCB) system. The transition system utilized for test nos. MGSPCB-1 through MGSPCB-3 consisted of a standard MGS that overlapped a series of F- shape PCB segments that approached the MGS at a 15H:1V flare. In the overlapped portion of the barrier systems, uniquely-designed blockout holders and a specialized W-beam end shoe mounting bracket were used to connect the systems. In test no. MGSPCB-1, a 5,079-lb (2,304-kg) pickup truck impacted the barrier at 63.2 mph (101.8 km/h) and 25.3 degrees. The barrier captured and redirected the 2270P vehicle, and the vehicle decelerations were within the recommended occupant risk limits. In test no. MGSPCB-2, a 2,601-lb (1,180-kg) car impacted the barrier at 65.1 mph (104.8 km/h) and 24.0 degrees. The barrier captured and redirected the 1100C vehicle, and the vehicle decelerations were within the recommended occupant risk limits. In test no. MGSPCB-3, a 5,177-lb (2,348-kg) pickup truck impacted the barrier at 63.1 mph (101.5 km/h) and 24.6 degrees. For this test, the system was impacted in the reverse direction. The barrier captured and redirected the 2270P vehicle, and the vehicle decelerations were within the recommended occupant risk limits. Based on the results of these successful crash tests, it is believed that the transition design detailed herein represents the first MASH TL- 3 crashworthy transition between the MGS and PCBs

Midwest Guardrail System (MGS) with an Omitted Post

The objective of this research study was to evaluate the MGS (31” tall W-beam guardrail) with an omitted post according to the safety performance criteria provided in MASH. A single full-scale crash test was conducted with the 2270P pickup truck in accordance with MASH test no. 3-11. The small car test, test no. 3-10, was deemed unnecessary as the pickup truck test would result in higher rail loads, a greater propensity for rail rupture, and a greater risk of failure. The test installation utilized standard 6-ft (1.8-m) long steel guardrail posts with 12-in. (305-mm) deep blockouts. A single post was omitted near the center of the 175-ft (53.3-m) long installation. Test no. MGSMP-1 resulted in the guardrail capturing and smoothly redirecting the 2270P vehicle. The vehicle remained upright, and all vehicle decelerations were within the recommended occupant risk limits. As such, the MGS with an omitted post satisfied the TL-3 safety performance criteria found in MASH. Following the full-scale crash testing, implementation guidance and recommendations were provided regarding the omission of a post within various MGS configurations, including MGS adjacent to 2:1 fill slopes, MGS on 8:1 approach slopes, MGS in combination with curbs, wood post MGS, non-blocked MGS, terminals and anchorages, MGS stiffness transition to thrie beam approach guardrail transitions, and MGS long-span systems

Cable-to-Post Attachments for Use in Non-Proprietary High-Tension Cable Median Barrier – Phase II

The objective of this study was to reevaluate and improve the existing cable-to-post attachment hardware that is utilized in the non-proprietary cable barrier being developed at MwRSF. The study focused on redesigning the bolted, tabbed bracket (V10) to eliminate the bolt, reduce the number of components per bracket, eliminate the need for tools during installation, and reduce the number of small parts. Three attachment concepts were selected for evaluation through dynamic testing: (1) the key plate attachment; (2) the wire lock pin attachment; and (3) the pinned back attachment. Each attachment prototype was subjected to two vertical and two lateral dynamic component tests to evaluate the release loads and fracture mechanisms of the brackets. Test results were compared to previous tests on the bolted tabbed bracket (V10). None of the three bracket attachment designs were found to satisfy all of the design criteria for an alternative bracket. The lack of fixity in the connection between the brackets and the post led to a variable position of the tabs within the keyway which frequently caused unsatisfactory release loads. Therefore, none of the three alternative attachment brackets were recommended for use within the prototype non-proprietary cable barrier

Heavy Truck and Bus Traversability at Highway-Rail Grade Crossings

NTC: 26-1121-0018-011MwRSF: TRP-03-392-18The objective of this research study was to provide recommendations for traversable highway-rail grade crossings for low, long wheelbase vehicles such as trucks and buses. A literature review was performed to gather information regarding highway-rail grade crossing guidelines, current laws concerning high-profile crossings and signage, crossing maintenance practices, previous work related to highway-rail grade crossing traversability for heavy trucks and buses, and accidents involving low, long wheelbase vehicles becoming high-centered on highway-rail grade crossings. Dimensions for low, long wheelbase trailers, buses, and recreational vehicles were compiled and utilized to determine the most critical vehicles. Drive tests were performed by a tractor-trailer to determine trailer suspension properties, and the information was used to increase the accuracy of vehicle simulation models. Simulations of various highway-rail grade crossings were performed with two vehicle models: a tractor-lowboy and a bus. A range of wheelbases for each vehicle model was tested to determine which vehicles became high-centered on crossings. Based on the results of the TruckSim simulations, a recommended profile for highway-rail grade crossings was recommended. Three highway-rail grade crossings located in Bellevue, Nebraska were 3D scanned to determine the crossing geometries. The three crossings were chosen due to scrape marks on the crossing surfaces seen with Google Maps Street View. The crossings were simulated and it was determined which wheelbases would cause vehicles to become high-centered