NCHRP Report 350 Testing of W-Beam Slotted-Rail Terminal

1997 ◽  
Vol 1599 (1) ◽  
pp. 22-31 ◽  
Author(s):  
King K. Mak ◽  
Hayes E. Ross ◽  
Roger P. Bligh ◽  
Wanda L. Menges
Keyword(s):  
High Speed ◽  
Safety Performance ◽  
The Other ◽  
Federal Aid ◽  
Speed Limits ◽  
Crash Testing ◽  
National Highway ◽  
Level 3 ◽  
Test Level ◽  
Highway System

Two slotted-rail terminal (SRT) designs, one for use on roadways with speed limits of 72.4 km/hr (45 mi/hr) or less and the other for high-speed facilities, were previously developed and successfully crash-tested in accordance with guidelines set forth in NCHRP Report 230. Those SRT designs have been approved by FHWA for use on federal-aid projects. However, FHWA has since adopted NCHRP Report 350 as the official guidelines for safety performance evaluation of roadside features and required that all roadside features to be used on the National Highway System be crash-tested in accordance with the NCHRP Report 350 guidelines by 1998. It is therefore necessary to modify and retest the SRT designs in accordance with NCHRP Report 350 guidelines. The modified SRT design has successfully met the guidelines set forth in NCHRP Report 350 for Test Level 3 conditions, that is, 100-km/hr (62.2 mi/hr) and the results of the crash testing. The modified SRT design has been approved by FHWA for use on the national highway system.

Midwest Guardrail System Adjacent to a 2:1 Slope

2008 ◽  
Vol 2060 (1) ◽  
pp. 74-83 ◽  
Author(s):  
Karla A. Polivka ◽  
Dean L. Sicking ◽  
Ronald K. Faller ◽  
Robert W. Bielenberg
Keyword(s):  
Performance Evaluation ◽  
High Speed ◽  
Evaluation Criteria ◽  
Break Point ◽  
Safety Performance ◽  
National Highway ◽  
The Cost ◽  
Steep Slopes ◽  
Economical Alternative ◽  
Highway System

A W-beam guardrail is often used to protect motorists from steep roadside slopes adjacent to high-speed roadways. Although previously designed systems have demonstrated acceptable safety performance, the long posts and half-post spacing have proven to be costly and introduce maintenance challenges. Using longer posts is more economical to users than having a system with posts installed at half-post spacing. Furthermore, the improved redirective capacity of the Midwest Guardrail System (MGS) provides the opportunity to eliminate the need for half-post spacing and thereby greatly reduces the cost of placing a barrier at the slope break point. A stiffened version of the MGS was developed for use adjacent to steep roadside slopes. The new design incorporates 2,743-mm (9-ft) long posts with 1,905-mm (75-in.) spacing. With the top of the W-beam mounted at a height of 787 mm (31 in.), this guardrail was successfully crash tested according to the currently proposed NCHRP Report 350 Update safety performance evaluation criteria. Hence, the stiffened MGS guardrail design with full post spacing is acceptable for use on the National Highway System. This new guardrail design will provide a safe and economical alternative for use along highways with steep slopes very close to the travelway.

Emissions Impact of Eliminating National Speed Limits: One Year Later

1997 ◽  
Vol 1587 (1) ◽  
pp. 113-120
Author(s):  
Maureen A. Mullen ◽  
James H. Wilson ◽  
Laura Gottsman ◽  
Robert B. Noland ◽  
William L. Schroeer
Keyword(s):  
Maximum Speed ◽  
Speed Limit ◽  
Oxides Of Nitrogen ◽  
Speed Limits ◽  
The Past ◽  
Volatile Organic ◽  
National Highway ◽  
One Year ◽  
The Impact ◽  
Highway System

The National Highway System (NHS) bill passed by Congress in November 1995 eliminated the national maximum speed limit. It has allowed states to set their own speed limits, which many have changed during the past year. This analysis examines the impact of speed limit changes 1 year after passage of the NHS. Oxides of nitrogen (NOx), carbon monoxide, and volatile organic compounds are analyzed and are found to have increased nationwide by up to 6, 7, and 2 percent, respectively. Much of the increase has occurred in western states, which generally have increased vehicle speeds more than in eastern and midwestern states. For example, in Texas NOx emissions are estimated to have increased by 35 percent due to large increases in highway and arterial speed limits.

Development of a 34-in. Tall Thrie-Beam Guardrail Transition to Accommodate Future Roadway Overlays

2019 ◽  
Vol 2673 (2) ◽  
pp. 489-501
Author(s):  
Scott K. Rosenbaugh ◽  
Ronald K. Faller ◽  
Jennifer D. Schmidt ◽  
Robert W. Bielenberg
Keyword(s):  
Full Scale ◽  
Safety Performance ◽  
Performance Criteria ◽  
Concrete Barriers ◽  
Before And After ◽  
Level 3 ◽  
Crash Tests ◽  
Test Level

Roadway resurfacing and overlay projects effectively reduce the height of roadside barriers placed adjacent to the roadway, which can negatively affect their crashworthiness. More recently, bridge rails and concrete barriers have been installed with slightly increased heights to account for future overlays. However, adjacent guardrails and approach transitions have not yet been modified to account for overlays. The objective of this project was to develop an increased-height approach guardrail transition (AGT) to be crashworthy both before and after roadway overlays of up to 3 in. The 34-in. tall, thrie-beam transition detailed here was designed such that the system would be at its nominal 31-in. height following a 3-in. roadway overlay. Additionally, the upstream end of the AGT incorporated a symmetric W-to-thrie transition segment that would be replaced by an asymmetric transition segment after an overlay to keep the W-beam guardrail upstream from the transition at its nominal 31-in. height. The 34-in. tall AGT was connected to a modified version of the standardized buttress to mitigate the risk of vehicle snag below the rail. The barrier system was evaluated through two full-scale crash tests in accordance with Test Level 3 (TL-3) of AASHTO’s Manual for Assessing Safety Hardware (MASH) and satisfied all safety performance criteria. Thus, the 34-in. tall AGT with modified transition buttress was determined to be crashworthy to MASH TL-3 standards. Finally, implementation guidance was provided for the 34-in. tall AGT and its crashworthy variations.

Crash Testing and Evaluation of Culvert-Mounted Midwest Guardrail System

2020 ◽  
Vol 2674 (7) ◽  
pp. 161-171
Author(s):  
Mojdeh Asadollahi Pajouh ◽  
Robert W. Bielenberg ◽  
Jennifer D. Schmidt-Rasmussen ◽  
Ronald K. Faller
Keyword(s):  
American Association ◽  
Water Drainage ◽  
Test Installation ◽  
State Highway ◽  
Crash Testing ◽  
Test Number ◽  
Box Culverts ◽  
Level 3 ◽  
Crash Tests ◽  
Test Level

Concrete box culverts are usually installed under roadways to allow water drainage without affecting the motoring public. Culvert openings can represent a hazard on the roadside when they do not extend outside of the clear zone, and often require safety treatments in the form of roadside barriers. In this study, a modified design of Midwest Guardrail System (MGS) was evaluated for installation on a low-fill culvert with the strong-post attachment using through-bolts and epoxy anchorage through full-scale crash testing. The test installation consisted of MGS with a 31 in. top rail height, supported by W6 × 9 posts, spaced at 37½ in., attached to a low-fill culvert’s top slab with a 12 in. offset from the back of the post to the culvert headwall. Two crash tests were conducted according to the American Association of State Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety Hardware (MASH) 2016 Test Level 3 impact safety criteria. In test number CMGS-1, a 2,428-lb car impacted the MGS attached to the culvert at a speed of 61.3 mph and at an angle of 25.1°. In test number CMGS-2, a 5,013-lb pickup truck impacted the MGS attached to the culvert at a speed of 62.8 mph and an angle of 25.7°. In both tests, the vehicle was safely redirected and captured. Both tests were deemed acceptable according to TL-3 safety criteria in MASH. Recommendations were made for the safe installation of MGS atop low-fill culverts as well as transitions from the standard MGS to the culvert-mounted MGS.

Test Level 2 Guardrail-to-Bridge Rail Transition Compatible with 31-in. Guardrail

2013 ◽  
Vol 2377 (1) ◽  
pp. 74-83
Author(s):  
R. P. Bligh ◽  
D. R. Arrington ◽  
R. Meza
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Transition Systems ◽  
Speed Test ◽  
Traffic Conditions ◽  
Level 3 ◽  
Common Application ◽  
Departments Of Transportation ◽  
Test Level ◽  
Level 2

Many state departments of transportation are in the process of updating their guardrail standards to comply with the AASHTO Manual for Assessing Safety Hardware (MASH) and guidance issued by FHWA on guardrail height. A key feature of the new systems is an increase in rail mounting height from 27 in. to 31 in. A common application of guardrails is shielding motorists from hazards at bridge approaches, including the end of the bridge rail. When a flexible-approach guardrail is attached to a rigid bridge rail, a transition section is needed to transition the stiffness properly from one system to another. A nested thrie beam transition system has been successfully tested to MASH guidelines and is compatible with a 31-in.-approach guardrail. However, it is cost-prohibitive to use this high-speed, Test Level 3 transition on all roadways. A low-cost transition was successfully evaluated under NCHRP Report 350 Test Level 2 (TL-2) impact conditions for use on lower-speed roadways. However, this TL-2 W-beam transition is 27 in. tall and is not compatible with the new 31-in. guardrail systems. This paper describes a new low-cost guardrail-to-bridge rail transition that was successfully developed and tested under MASH TL-2 conditions. The transition is compatible with new 31-in. guardrails and can connect to rigid concrete bridge rails. The transition is considered suitable for implementation on roadways that have traffic conditions appropriate for the use of TL-2 safety hardware. Use of this system would provide significant savings in both material and installation costs compared with high-speed transition systems.

Approach Guardrail Transition for Single-Slope Concrete Barriers

1996 ◽  
Vol 1528 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Ronald K. Faller ◽  
Ketil Soyland ◽  
Dean L. Sicking
Keyword(s):  
Performance Evaluation ◽  
Full Scale ◽  
Safety Performance ◽  
Vehicle Crash ◽  
Concrete Barriers ◽  
Level 3 ◽  
Crash Tests ◽  
Test Level

An approach guardrail transition for use with the single-slope concrete median barrier was developed and crash tested. The transition was constructed with 3.43-mm-thick (10-gauge) thrie-beam rail and was supported by nine W6 × 9 steel posts. Post spacings consisted of one at 292 mm (11.5 in.), five at 476 mm (1 ft 6.75 in.), and three at 952 mm (3 ft 1.5 in.). A structural tube spacer block (TS 7 × 4 × 3/16) was also developed for use with the thrie-beam rail. Two full-scale vehicle crash tests were performed, and the system was shown to meet the Test Level 3 requirements specified in NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features.

Low-Cost Median Barrier Gate

2012 ◽  
Vol 2309 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Roger P. Bligh ◽  
Dusty R. Arrington ◽  
Nauman M. Sheikh ◽  
Rory Meza ◽  
Chiara Silvestri
Keyword(s):  
Low Cost ◽  
General Purpose ◽  
The Other ◽  
Managed Lanes ◽  
Steel Tubes ◽  
Impact Performance ◽  
Single Person ◽  
Level 3 ◽  
Test Level ◽  
Limit Access

Median barriers are commonly used to separate opposing lanes of traffic on divided highways and to separate managed lanes from general purpose lanes. Concrete median barriers (CMBs) are often preferred on urban freeways with narrow medians because of their minimal deflection and low maintenance. However, long, continuous runs of CMBs limit access of emergency and maintenance vehicles to the other side of a roadway or a managed lane. Implementation of crashworthy median barrier gates at these locations can maintain the desired level of median protection for motorists while offering improved cross-median access for emergency and maintenance vehicles. A new median barrier gate was developed and crash tested. The gate spans a 30-ft opening in a CMB and consists of two vertically stacked 12- x 12- x ¼-in. steel tubes connected to steel end brackets with 2¼-in. diameter steel pins. The gate is economical to fabricate and install. It can be manually operated by a single person and is designed to accommodate reversible traffic flow on both sides of the median and be operable in both directions on each end. The median barrier gate satisfies the criteria for impact performance of Test Level 3 of the Manual for Assessing Safety Hardware and is considered suitable for implementation on divided highways at locations where cross-median access is desired.

scholarly journals Development of a Test Level 3 Transition Between Guardrail and Portable Concrete Barriers

2017 ◽  
Vol 2638 (1) ◽  
pp. 77-87 ◽  
Author(s):  
Robert W. Bielenberg ◽  
David Gutierrez ◽  
Ronald K. Faller ◽  
John D. Reid ◽  
Phil Tenhulzen
Keyword(s):  
Systems Design ◽  
Road Construction ◽  
Full Scale ◽  
Performance Criteria ◽  
Work Zones ◽  
Design Concepts ◽  
Crash Testing ◽  
Concrete Barriers ◽  
Level 3 ◽  
Test Level

Road construction often requires that work zones be created and shielded by portable concrete barriers (PCBs) to protect workers and equipment from errant vehicles as well as to prevent motorists from striking other roadside hazards. For an existing W-beam guardrail system installed adjacent to the roadway and near the work zone, guardrail sections are removed so a PCB system can be placed. A study was done to develop a crashworthy transition between W-beam guardrail and PCB systems. Design concepts were developed and refined through computer simulation with LS-DYNA. Additionally, a study of critical impact points was conducted to determine impact locations for full-scale crash testing. The design effort resulted in a new system consisting of a Midwest Guardrail System that overlapped a series of F-shape PCB segments placed at a 15:1 flare. In the overlapped region of the barrier systems, uniquely designed blockout supports and a specialized W-beam end shoe mounting bracket were used to connect the systems. Three full-scale vehicle crash tests were successfully conducted according to the Manual for Assessing Safety Hardware Test Level 3 safety performance criteria. Because of the successful test results, a Test Level 3 crashworthy guardrail-to-PCB transition system is now available for protecting motorists, workers, and equipment in work zones.

Approach Guardrail Transition for Concrete Safety Shape Barriers

1998 ◽  
Vol 1647 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Ronald K. Faller ◽  
John D. Reid ◽  
John R. Rohde
Keyword(s):  
Performance Evaluation ◽  
Transition System ◽  
Safety Performance ◽  
Level 3 ◽  
Test Level

An approach guardrail transition for use with concrete safety shape barriers was developed and crash-tested. The transition was constructed with two nested thrie-beam rails, measuring 2.66 mm thick, and supported by nine W150 x 13.5 steel posts. Post spacings consisted of one at 292 mm, five at 476 mm, and three at 952 mm. Structural tube spacer blockouts were used in the transition system. The system successfully met the Test Level 3 requirements specified in NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features.

Long-Span Guardrail System for Culvert Applications

2000 ◽  
Vol 1720 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Ronald K. Faller ◽  
Dean L. Sicking ◽  
Karla A. Polivka ◽  
John R. Rohde ◽  
Bob W. Bielenberg
Keyword(s):  
Simulation Modeling ◽  
Research Study ◽  
Full Scale ◽  
Wood Block ◽  
Long Span ◽  
Crash Testing ◽  
Vehicle Crash ◽  
Level 3 ◽  
Crash Tests ◽  
Test Level

A long-span guardrail for use over low-fill culverts was developed and successfully crash tested. The guardrail system was configured with 30.48 m of nested, 12-gauge W-beam rail and centered around a 7.62-m-long unsupported span. The nested W-beam rail was supported by 16 W152×13.4 steel posts and 6 standard CRT posts, each with two 150-mm×200×360 mm wood block-outs. Each post was 1830 mm long. Post spacings were 1905 mm on center, except for the 7.62-m spacing between the two CRT posts surrounding the long span. The research study included computer simulation modeling with Barrier VII and full-scale vehicle crash testing, using 3/4-ton (680-kg) pickup trucks in accordance with the Test Level 3 (TL-3) requirements specified in NCHRP Report 350. Three full-scale vehicle crash tests were performed. The first test was unsuccessful because of severe vehicle penetration into the guardrail system. This penetration resulted from a loss of rail tensile capacity during vehicle redirection when the swagged fitting on the cable anchor assembly failed. A second test was performed on the same design, which contained a new cable anchor assembly. During vehicle redirection, the pickup truck rolled over and the test was considered a failure. The long-span system was subsequently redesigned to incorporate double block-outs on the CRT posts and crash tested again. Following the successful third test, the long-span guardrail system was determined to meet TL-3 criteria.

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