Engineering Commons^™

Investigation And Modification Of Single-Post Aluminum Sign Supports For Mash Crashworthiness, Rodrigo Quintero

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

Traffic signs are used to display information to drivers and are one of the most commonly encountered roadside structures. Although they are a vital traffic control device, signs can pose a significant safety risk to errant drivers due to their extensive placement and proximity to the roadway. Therefore, traffic signs and their supports must be designed with crashworthiness in mind to reduce the likelihood of injury in the event of a vehicle impact. Prior to 2009, these systems were evaluated using the crash testing criteria found in the National Cooperative Highway Research Program (NCHRP) Report No. 350 [1]. Currently, they …

Crashworthy Perforated Square Steel Tube (Psst) Mailbox Support – Phase I, Robert W. Bielenberg, Cody S. Stolle, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

Federal requirements have made it mandatory that safe mailbox support systems be designed to yield or breakaway whenimpacted by a vehicle. The Nebraska Department of Transportation (NDOT) has previously used a non-proprietary, U-channel post mailbox support that was evaluated at the Midwest Roadside Safety Facility (MwRSF) in the 1980's. NDOT desires that the mailbox support be updated to meet MASH 2016 TL-3 safety performance criteria and be redesigned to use perforated square steel tubing (PSST) for the mailbox support post.

The objective of this research project is to develop a non-proprietary mailbox support using PSST support posts that is MASH …

Development Of A Next-Generation Non-Proprietary Portable Concrete Barrier, Riley Ruskamp

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

Portable concrete barriers (PCBs) are segmented barriers made of precast concrete units that are connected by various load-bearing hardware. PCBs are typically used to shield work zones by redirecting errant vehicles upon impact with the barrier system. Most commonly-available PCBs have demonstrated performance issues arising from the sloped face of the barrier, which encourages vehicles to pitch and roll during impact, potentially resulting in vehicle rollover. Concerns also exist regarding the large dynamic deflections exhibited by these systems that can encroach upon the protected work zone or require anchoring to prevent large displacements. In addition to these concerns, the American …

Mash 2016 Test Level 3 And Test Level 4 Evaluation Of Roadside Safety Barrier With Pedestrian Features, Miguel Angel Hinojosa Palacios

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

The Minnesota Department of Transportation (MnDOT) desires to use a vehicle, bicycle, and pedestrian combination bridge railing system along pedestrian and bicycle bridge paths. The system was evaluated per MASH 2016.

In full-scale crash test no. MNPD-3, the system was evaluated according to MASH test designation no. 3-11. The 2014 Dodge Ram 1500 crew cab pickup truck impacted the system 71¼ in. upstream from the centerline of post no. 4 with a speed of 63.4 mph at an angle of 25.3 degrees. The combination railing system was found to meet the AASHTO MASH 2016 TL-3 impact safety criteria.

MnDOT uses …

Development Of A Mash Test Level 4 Open Concrete Bridge Rail, Jacob Delone

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

An open concrete bridge rail was designed and developed according to safety performance guidelines in the American Association of State Highway Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). Systems designed and developed under previous guidance were studied, and their geometric information and full-scale crash testing performance was studied to establish the geometry of the new bridge rail. Yield-Line Theory and the AASHTO Post and Beam design methods were studied, and a modified version of the AASHTO Post and Beam method was utilized to determine the capacity of the new open concrete bridge rail. …

Development Of A Mash Tl-4 Steel, Side-Mounted, Beam-And-Post, Bridge Rail, Oscar Pena

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

A new steel, side-mounted, beam-and-post, bridge rail was designed, crash-tested, and evaluated according to safety performance guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). The new bridge rail system was designed to be compatible to multiple concrete bridge decks utilized by the States of Illinois and Ohio. Bridge rail configurations were designed and optimized based on weight per foot, constructability, and safety. Post-to-rail and rail-to-rail connections were designed for the new bridge rail. Several concepts for these connections were configured, and after discussion with representatives …

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 …

Cable-To-Post Attachments For Use In Non-Proprietary High-Tension Cable Median Barrier – Phase Ii, Scott K. Rosenbaugh, Robert W. Bielenberg, Brandt M. Humphrey, Ronald K. Faller, John D. Reid, Karla A. Lechtenberg

Nebraska Department of Transportation: Research Reports

The research objectives reported herein were based on further development of cable-to-post attachment hardware for use in the non-proprietary high-tension cable barrier system. Specifically, this project aimed to develop and evaluate alternative attachment designs for the bolted, tabbed bracket and evaluate the use of a larger diameter, keeper rod for use in the top cable attachment. From a group of over 25 alternative attachment concepts, two tabbed bracket designs were selected for evaluation through dynamic component testing: 1) the lateral shear plate attachment and 2) the drop-in shear plate attachment. The drop-in shear plate concept did not perform as intended, …

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, …

Development Of Socketed Foundations For S3x5.7 Posts, Scott K. Rosenbaugh, Tyler L. Schmidt, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

The objective of this study was to develop a socketed foundation for use with the S3x5.7 (S76x8.5) weak post. The design focused on cylindrical, reinforced concrete foundations with a steel tube placed in the center for use as the socket. The foundation was to prevent both damage and displacements exceeding 1 in. (25 mm), as measured at groundline, during an impact event. To evaluate various foundation designs, ten dynamic bogie tests were conducted over three separate rounds of testing. Round 1 was conducted in a weak, sandy soil; Round 2 was conducted in a strong, stiff soil; and Round 3 …

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 …

Calibration Of The Highway Safety Manual For Missouri, Carlos Sun Ph.D., P.E., Jd, Henry Brown Msce, P.E., Praveen Edara Ph.D., P.E., Boris Carlos, Kyuongmin Andrew Nam

Mid-America Transportation Center: Final Reports and Technical Briefs

The new Highway Safety Manual (HSM) contains predictive models that need to be calibrated to local conditions. This calibration process requires detailed data types, such as crash frequencies, traffic volumes, geometrics, and land-use. The HSM does not document in detail techniques for gathering such data, since data systems vary significantly across states. The calibration process also requires certain decisions, such as the correct sampling approach, determination of the minimum segment length, the treatment of left-turn phasing, and the inclusion or exclusion of speed-change lane crashes. This report describes the challenges, practical solutions, and results from a statewide HSM calibration in …

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 …

Development And Recommendations For A Non-Proprietary, High-Tension, Cable End Terminal System, Ryan J. Terpsma

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

Cable guardrail systems have been increasing in popularity in recent years due to several perceived benefits over the commonly used W-beam guardrail. A non-proprietary design was desired as an alternative to the many proprietary designs available. A non-proprietary, high-tension cable end terminal was necessary to accompany the non-proprietary, high-tension cable guardrail system under development.

The objective of this research project was to develop design recommendations for a non-proprietary, high-tension cable end terminal. An analysis of several cable guardrail end terminals was undertaken to identify any common features that may prove to be beneficial or detrimental to end terminal designs. Next, …

Cable Median Barrier Failure Analysis And Prevention, Dean L. Sicking, Cody S. Stolle

Mid-America Transportation Center: Final Reports and Technical Briefs

Cross-median crashes have been identified as one of the highest injury or fatality risk crash types. Although crossmedian crashes account for only 2% to 5% of all median crash events, they are disproportionately represented in the number and frequency of fatalities on interstate roadways. Many states have utilized cable median barriers to reduce the risk of cross-median crashes, frequently with great success. However, cable median barriers are also fixed obstacles to errant vehicles. Cable median barriers can place occupants at increased risk of severe injury or fatality if the barrier fails to adequately contain and redirect errant vehicles, resulting in …

Roadside Grading Guidance, Kevin D. Schrum

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

Provisions for the design of roadside foreslopes are not readily available, and as a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore, a design guide was created to lend consistency to the design of these foreslopes while maintaining the most economical and safe design.

This design guide was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to …

Development Of Advanced Finite Element Material Models For Cable Barrier Wire Rope, John D. Reid, Karla A. Lechtenberg, Cody S. Stolle

Mid-America Transportation Center: Final Reports and Technical Briefs

An improved LS-DYNA model of ¾-in. (19-mm) diameter 3x7 wire rope commonly used in roadside cable guardrail installations has been developed. A Belytschko-Schwer beam element was selected along with material *MAT_166. Numerical noise was reduced using part stiffness damping with a coefficient of 2%, and frequency range damping with a coefficient of 12%. The optimum element length based on timestep, accuracy, and computational cost was determined to be between 0.4 and 0.8 in. (10-20 mm). Dynamic component tests were conducted on wire rope to determine material properties. These tests were simulated and the results compared to the physical tests. 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 …