Engineering Commons^™

Prioritization Of Research On Bridge Railings For Use On Timber Deck Bridges And Development Of Two Glulam Bridge Railing Systems, Jared Duren

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

In the past, many timber bridge railings, bridge railings for use on timber deck bridges, and approach guardrail transition systems to accompany these railings, have been developed to meet different impact safety criteria. Through an extensive literature review, the design details of these systems were identified and organized. A survey was then developed and distributed to multiple government agencies and timber industry members to identify their desire for these bridge railing and approach guardrail transition systems to be developed to meet current American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) impact safety criteria. …

Evaluation Of Flared Approach Guardrail Transitions And Mash 2270p Ram Vehicle Model Improvements, Ryan F. Bickhaus

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The objective of this research study was to use computer simulation to identify the critical flare rate for flaring approach guardrail transitions (AGTs) away from the primary roadway. AGTs installed with a flared configuration result in a length of need (LON) reduction as well as an increase in the clear zone area in front of the barrier, which would reduce both installation cost and crash frequency. The research focused on the determination of the maximum allowable flare rate that could safely be utilized with 31-in. (787-mm) tall thrie-beam AGTs without concrete curbs that utilize the Midwest Guardrail System (MGS) upstream …

In-Service Performance Evaluation Of Concrete Sloped End Treatments In Iowa, Jessica Lingenfelter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Sloped end treatments were historically developed as low-cost, low-maintenance end treatments for rigid features like concrete barriers and bridge rails. Crash testing indicated that sloped end treatments are associated with significant instability for impacting vehicles. However, the in-service performance of these features has not been evaluated. An in-service performance evaluation (ISPE) was performed to evaluate vehicle crashes with sloped end treatments in Iowa between 2008 and 2017. Researchers generated a geographic inventory of sloped end treatment locations, reviewed crash narratives and scene diagrams for crashes near these sloped end treatments, and calculated an estimated crash rate and crash cost for …

Investigation Of A Tractor-Tank Trailer Roadside Containment Barrier, Dean L. Whitfield

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The objective of this research project was to develop a new, cost-effective, Manual for Assessing Safety Hardware (MASH) Test Level 6 (TL-6) barrier. A literature review on prior Test Level 5 and Test Level 6 barriers was conducted, and the cost of current TL-5 and TL-6 barriers was established. Existing and modified design procedures for roadside barrier were reviewed as well as current TL-6 design forces. A preliminary TL-6 truck model was developed in LS-DYNA. The minimum barrier height to contain a tractor-tank vehicle was determined to be 62 in. for a rigid, vertical-faced barrier through LS-DYNA computer simulation. New …

Mash Test Nos. 3-11 And 3-10 On A Non-Proprietary Cable Median Barrier, Justine E. Kohtz, Robert W. Bielenberg, Scott K. Rosenbaugh, Ronald K. Faller, Karla A. Lechtenberg, John D. Reid

Nebraska Department of Transportation: Research Reports

The Midwest States Pooled Fund has been developing a new non-proprietary cable median barrier. This system incorporates four evenly spaced cables, Midwest Weak Posts spaced at 8 to 16 ft (2.4 to 4.9 m) intervals, and a bolted, tabbed bracket to attach the cables to each post. Full-scale crash testing was needed to evaluate the barrier’s safety performance. According to the Manual for Assessing Safety Hardware (MASH) updated/proposed testing matrix for cable barriers installed within a 6H:1V or median ditch, a series of eight full-scale tests are required to evaluate the safety performance of a system. A ninth test is …

Continued Development Of A Non-Proprietary, High-Tension, Cable End Terminal System, Jennifer D. Schmidt, Robert W. Bielenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

A non-proprietary, cable guardrail system is currently under development for the Midwest States Pooled Fund Program. A cable guardrail end terminal was necessary to accompany the cable guardrail system. The objective of this research project was to develop design recommendations for the cable end terminal. Bogie testing that was previously completed on a design concept indicated delayed cable release, which was an undesired performance that led to vehicle instabilities. Several design changes were recommended for better end terminal performance and to reflect the changes made to the cable median barrier. An LS-DYNA model of the modified cable end terminal was …

Midwest Guardrail System (Mgs) With An Omitted Post, Jessica L. Lingenfelter, Scott Rosenbaugh, Robert W. Bielenberg, Karla A. Lechtenberg, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

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 …

Performance Characteristics Of Posts Embedded In Soil, Brandt M. Humphrey, Karla A. Lechtenberg, John D. Reid, Ronald K. Faller, James C. Holloway

Nebraska Department of Transportation: Research Reports

The primary objective of this research study was to determine the post-soil impact reaction of W6x8.5 (W150x12.6) steel posts and 6-in. x 8-in. (152-mm x 203-mm) Southern Yellow Pine (SYP) posts, specifically along the weak axis. Five bogie tests were conducted on W6x8.5 (W150x12.6) A992 steel posts with a length of 72 in. with embedment depths ranging between of 24 and 40 in. (610 and 1,016 mm). Four bogies tests were conducted on 6-in. x 8-in. (152 mm x 203 mm) SYP posts embedded at depths ranging between 30 and 40 in. (735 and 1,016 mm). The target impact conditions …

Design Of An Improved Post For Use In A Non-Proprietary High-Tension Cable Median Barrier, Robert W. Bielenberg, Ronald K. Faller, Karla A. Lechtenberg, Tyler L. Schmidt, Scott K. Rosenbaugh, John D. Reid, Dean L. Sicking

Nebraska Department of Transportation: Research Reports

The objective of this research study was to develop a revised post section for the non-proprietary high-tension cable median barrier that improved the safety and function of the post by lowering strong-axis forces. A total of twenty dynamic component tests were performed, along with one cable pull test – ten tests with the 7-gauge C-section post, eight with the 10-gauge C-Section posts, and three with the Midwest Weak Post (MWP). The tests were conducted with the posts installed in either a compacted, crushed limestone soil or a rigid sleeve in order to determine the force vs. deflection and energy vs. …

Conceptual Development Of An Impact-Attenuation System For Intersecting Roadways, Joseph G. Putjenter

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Longitudinal barriers are commonly used to shield hazards, including stiff bridge rail ends and slopes. In some locations, a secondary roadway intersects the primary roadway within the guardrail’s length-of-need (LON). Some intersections have as little as 15 ft (4.6 m) between the intersection and beginning of the bridge railing, which require short-radius guardrail systems. No short-radius systems have been tested and approved to current impact safety standards for shielding hazards with these conditions.

Site conditions provided by the Nebraska Department of Roads were used to determine the constraints for a new safety treatment for intersecting roadways and include intersection radii, …

Increased Span Length For The Mgs Long-Span Guardrail System, Nicholas A. Weiland

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Long-span guardrail systems have been recognized as an effective means of shielding low-fill culverts while minimizing construction efforts and limiting culvert damage and repair. The current MGS long-span design provided the capability to span unsupported lengths up to 25 ft (7.6 m) without the use of nested guardrail. The excellent performance of the MGS long-span system in full-scale crash tests suggested that longer span lengths may be possible with the current design.

A detailed analysis of the MGS long-span guardrail system was performed using the finite element software program LS-DYNA^®. It was shown that the MGS long-span design …

Development Of A Mash Tl-3 Transition Between Guardrail And Portable Concrete Barriers, David A. Gutierrez

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Often, road construction causes the need to create a work zone. In these scenarios, portable concrete barriers (PCBs) are typically installed to shield workers and equipment from errant vehicles as well as 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 in order to place the portable concrete barrier system. The focus of this research study was to develop a proper stiffness transition between W-beam guardrail and portable concrete barrier systems. This research effort was accomplished through development and refinement of design …

Zone Of Intrusion For Permanent 9.1-Degree Single Slope Concrete Barriers, Cale J. Stolle

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Three WDOT 9.1-degree single-slope concrete barriers, with top heights of 36 in. (914 mm), 42 in. (1,067 mm), and 56 in. (1,422 mm) (Standard 14B32), were analyzed for Zone of Intrusion (ZOI)’ and working width using nonlinear finite element analysis (FEA). Tire-barrier friction, vehicle-barrier friction, barrier stiffness, mesh size, tire deflation, and suspension component failures were all found to have effects on simulation results. The zone of intrusion and working width were evaluated for each barrier under varying tire deflation and suspension failure conditions and determined to have a maximum value of 12.2 in. (310 mm) for the front fender …

Identification Of A Maximum Guardrail Height For The Midwest Guardrail System Using Computer Simulation, Ramen D. Julin

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

W-beam guardrails are by far the most common restraint system used along both local and major roadways. Traditionally, these restraint systems have been full-scale crash tested with a rail height ranging between 27 in. and 32 in. However, the maximum rail height which allows for safe performance of guardrails, especially in impacts involving small vehicles, has never been identified.

The main concern associated with an increase of the rail height is that small vehicles, because of their low profile, may have a tendency to lift the rail and penetrate the barrier. The objective of this project was to determine the …

Safety Investigation And Guidance For Work-Zone Devices In Freight Transportation Systems Subjected To Passenger Car And Truck Impacts With New Crash Standards, Ronald K. Faller Ph.D., P.E., Dean L. Sicking Ph.D., P.E., Karla A. Lechtenberg M.S.C.E., E.I.T., James C. Holloway M.S.C.E., E.I.T., Jennifer D. Schmidt

Mid-America Transportation Center: Final Reports and Technical Briefs

Crashworthy, work-zone, portable sign support systems accepted under NCHRP Report No. 350 were analyzed to predict their safety peformance according to the TL-3 MASH evaluation criteria. An analysis was conducted to determine which hardware parameters of sign support systems would likely contribute to the safety performance with MASH. The acuracy of the method was evaluated through full-scale crash testing. Four full-scale crash tests were conducted with a pickup truck. Two tall-mounted, sign support systems with aluminum sign panels failed the MASH criteria due to windshield penetration. One low-mounted system with a vinyl, roll-up sign panel failed the MASH criteria due …