Mash Tl 3 Transition Between Median Guardrail And Median Concrete Barrier
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Mash Tl 3 Transition Between Median Guardrail And Median Concrete Barrier
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Author : Akram Y. Abu-Odeh
language : en
Publisher:
Release Date : 2021
Mash Tl 3 Transition Between Median Guardrail And Median Concrete Barrier written by Akram Y. Abu-Odeh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Automobiles categories.
The purpose of this research was to develop a Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) compliant transition between a median guardrail and median concrete barrier, and then test the design according to MASH TL-3 crash testing guidelines. The design was developed using finite element computer simulations. This report provides details on the computer simulations, the Texas Department of Transportation (TxDOT) median transition system, the crash tests and results, and the performance assessment of the median transition for MASH TL-3 transition evaluation criteria. The TxDOT median transition met the performance criteria for MASH TL-3 transitions.
Development Of A Tl 3 F Shape Temporary Concrete Median Barrier
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Author : Ronald K. Faller
language : en
Publisher:
Release Date : 1996
Development Of A Tl 3 F Shape Temporary Concrete Median Barrier written by Ronald K. Faller and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996 with Median strips categories.
Work zones often require the use of temporary concrete barriers (TCBs) within a limited area to provide protection for construction workers. In situations where an existing guardrail is immediately adjacent to the construction hazards that need to be shielded, highway designers must either connect the guardrail to the temporary barrier or replace it with TCB. Although interconnecting the two barrier systems represents the more convenient option, at present no suitable solutions have been made available. A transition from guardrail to temporary barriers may not need to be nearly as stiff as a conventional approach transitions. However, it must provide sufficient stiffness and strength to prevent pocketing as well as to shield the end of the concrete barrier to prevent serious wheel snag. In addition, considerations must be made for transitioning from the TCB to the guardrail, anchoring the TCB system, and the potential use of tie-downs to limit TCB deflection. TCBs are connected and transitioned to many types of barriers. Unfortunately, little effort has been devoted to this issue. The only transitions previously developed have been between TCBs and safety shaped concrete barriers and TCBs and permanent concrete median barriers. Transitions between TCBs and other common barrier types, such as guardrail, have typically not been full-scale crash tested and may pose a serious hazard to motorists during an impact. Transitions between two barrier types generally are designed with the assumption that it is more critical to transition from a less stiff barrier to a stiffer barrier due to concerns for pocketing and snag on the stiffer barrier system. However, in the case of a TCB system, design of the transition can be more complex. Design of a transition between TCB and guardrail must consider several factors: (1) Connection of the guardrail on the upstream or downstream end of the TCB system - The location of the guardrail on either the upstream or downstream end of the transition will largely affect the transition along with other factors. For example, the attachment of the guardrail to the downstream end of an unanchored, free-standing TCB system would require a transition. This could be as simple as using tie-down anchorages on the TCB segments to increase their stiffness prior to the guardrail attachment. Conversely, attachment of the guardrail to the upstream end of a free-standing, TCB system would require a transition as well. However, this type of transition would require stiffening the guardrail as it approached the TCB. (2) Anchorage of the end of the TCB system - The location and design of the end anchorage for the TCB system will largely determine the stiffness of the TCB end as compared to the guardrail as well as the transition configuration. (3) Free-standing barrier vs. tie-down anchorage - The stiffness of the TCB section varies depending on whether the barrier segments use any form of tie-down anchorage. The design of the transition between the rail and the TCB would change depending on whether the barrier segments were free-standing or anchored. (4) Direction of traffic - The transition design may depend on the potential for two-way traffic or reverse impacts. Due to the wide range of factors affecting the design of a TCB to guardrail transition, it is necessary to develop a better understanding of the most common and most critical transition installations. Then, a transition design could be developed to meet those needs. It is anticipated that this transition design would be developed around the F-shape, TCB segment and the recently developed Midwest Guardrail System (MGS). The research study recommended herein would primarily be directed toward improving the safety and minimizing risk for the motoring public traveling within our nation's work-zones and on our highways and roadways. More specifically, this project would address the goal of the Smart Work Zone Deployment Initiative, which is "to develop improved methods and products for addressing safety and mobility in work zones by evaluating new technologies and methods, thereby enhancing safety and efficiency of traffic operations and highway workers. The project is a public/private partnership between the sponsoring public transportation agencies in several Midwestern States, the Federal Highway Administration (FHWA), private technology providers and university transportation researchers." The overall objective of this research effort is to develop a MASH TL-3 transition design between TCBs and the MGS. The design of the transition would focus on a representative selection of state departments of transportation (DOTs) highest priority configuration. Due to the large number of unknowns, this phase of the project will focus on the development of design concepts for the highest priority transition need. Full-scale crash testing of the proposed transition design is not a part of this project and may be performed in a future phase of the project. This research effort will begin with identifying and quantifying the most pressing TCB to guardrail transition needs. Although a need to develop configurations for most, if not all, of the TCB to guardrail transition needs may exist, this project will address the highest priority need. Thus, the state DOTs of the Midwest States Pooled Fund Program will be surveyed to identify the highest priority TCB to guardrail transition need. After the critical transition need is identified, potential transition concepts and prototype designs will be brainstormed. Computer simulations with LS-DYNA, a non-linear explicit finite element code, will be used to investigate and evaluate the concepts and prototype designs. CAD details for the proposed transition design will be prepared. A summary report detailing the research effort will be compiled and will include recommendations for future full-scale crash testing of the TCB to guardrail transition as well as recommendations for further development of TCB to guardrail transitions. The research study is directed toward improving the safety by minimizing the risk for the motoring public traveling within our nation's work-zones and on our highways and roadways. Since W-beam guardrail has proven to provide better safety performance than temporary concrete barriers, the development of an effective transition between the two can help preserve guardrails outside the immediate work-zone area, thus providing an overall higher level of safety for motorists. The new transition would also eliminate the use of an unproven connection between guardrail and temporary barriers. Further, limiting the use of temporary concrete barriers strictly to the work zone area will also minimize the traffic disruption that these barriers can create to motorists passing in work zones. Following the development efforts, a research report will be prepared that summarizes the results of the study. If warranted, a formal paper will be prepared and submitted for publication in a refereed journal, such as a Transportation Research Record, so that dissemination and distribution of the final research results will provide the most significant impact in terms of safety benefit for the motoring public
Evaluation Of Existing Roadside Safety Hardware Using Manual For Assessing Safety Hardware Mash Criteria
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Author : D. Lance Bullard
language : en
Publisher:
Release Date : 2010
Evaluation Of Existing Roadside Safety Hardware Using Manual For Assessing Safety Hardware Mash Criteria written by D. Lance Bullard and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Roads categories.
TRB's National Cooperative Highway Research Program (NCHRP) Research Results Digest 349: Evaluation of Existing Roadside Safety Hardware Using Manual for Assessing Safety Hardware (MASH) Criteria explores the safety performance of widely used non-proprietary roadside safety features by using MASH. Examples of features evaluated include longitudinal barriers (excluding bridge railings), terminals and crash cushions, transitions, and breakaway supports. The complete report on the project that developed NCHRP RRD 349 was published as NCHRP Web-Only Document 157.
Roadside Design Guide
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Author : American Association of State Highway and Transportation Officials. Task Force for Roadside Safety
language : en
Publisher: AASHTO
Release Date : 2011
Roadside Design Guide written by American Association of State Highway and Transportation Officials. Task Force for Roadside Safety and has been published by AASHTO this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Technology & Engineering categories.
"The Roadside Design Guide presents a synthesis of current information and operating practices related to roadside safety and is written in dual units-metric and U.S. Customary. This book is a guide. It is not a standard, nor is it a design policy. It is intended to use as a resource document from which individual highway agencies can develop standards and policies. Although much of the material in the guide can be considered universal in its application, several recommendations are subjective in nature and may need modification to fit local conditions. However, it is important that significant deviations from the guide be based on operational experience and objective analysis. The 2011 edition of the AASHTO Roadside Design Guide has been updated to include hardware that has met the evaluation criteria contained in the National Cooperative Highway Research Program (NCHRP) Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features and begins to detail the most current evaluation criteria contained under the Manual for Assessing Safety Hardware, 2009 (MASH). For the most part, roadside hardware tested and accepted under older guidelines that are no longer applicable has not been excluded in this edition." -- AASHTO website.
Research Results Digest
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Author :
language : en
Publisher:
Release Date : 2010
Research Results Digest written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Highway research categories.
Development Of A Mash Tl 3 Transition Between Guardrail And Portable Concrete Barriers
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Author : David A. Gutierrez
language : en
Publisher:
Release Date : 2014
Development Of A Mash Tl 3 Transition Between Guardrail And Portable Concrete Barriers written by David A. Gutierrez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Road work zones categories.
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 concepts using computer simulation with LS-DYNA. Several design concepts were simulated, and design metrics were used to evaluate and refine each concept. These concepts were then analyzed and ranked based on feasibility, likelihood of success, and ease of installation. The rankings were presented to the Technical Advisory Committee (TAC) for selection of a preferred design alternative. Next, a Critical Impact Point (CIP) study was conducted, while additional analyses were performed to determine the critical attachment location and a reduced installation length for the portable concrete barriers. Finally, an additional simulation effort was conducted in order to evaluate the safety performance of the transition system under reverse-direction impact scenarios as well as to select the CIP. Recommendations were also provided for conducting a Phase II study and evaluating the nested Midwest Guardrail System (MGS) configuration using three Test Level 3 (TL-3) full-scale crash tests according to the criteria provided in the Manual for Assessing Safety Hardware, as published by the American Association of Safety Highway and Transportation Officials (AASHTO).
Design And Mash Tl 3 Evaluation Of Surface Mounted Median Guardrail
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Author : Nauman Mansoor Sheikh
language : en
Publisher:
Release Date : 2022
Design And Mash Tl 3 Evaluation Of Surface Mounted Median Guardrail written by Nauman Mansoor Sheikh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Automobiles categories.
This report presents the development and crash testing of a surface-mounted median guardrail on concrete. The research team developed several preliminary design concepts of the median guardrail. One of these was selected by the Texas Department of Transportation for further development through finite element simulation analysis and full-scale crash testing. The safety performance of the final design of the surface-mounted median guardrail was evaluated in accordance with the guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware (MASH), Second Edition (1). The design was evaluated for Test Level 3 (TL-3) of MASH, for which the following two crash tests were performed: 1. MASH Test 3-10: An 1100C small passenger sedan weighing 2420 lb., impacting the median guardrail while traveling at a speed and angle of 62 mi/h and 25 degrees. 2. MASH Test 3-11: A 2270P pickup truck weighing 5000 lb., impacting the median guardrail while traveling at a speed and angle of 62 mi/h and 25 degrees. The new surface-mounted median guardrail design passed the MASH evaluation criteria for both tests. This report provides details on the surface-mounted median guardrail, the crash tests and results, and the performance assessment of the median guardrail using the evaluation criteria of MASH TL-3 for longitudinal barriers.
Development Of Mash Tl 3 Transitions For Cast In Place Concrete Barriers
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Author : Nauman Mansoor Sheikh
language : en
Publisher:
Release Date : 2020
Development Of Mash Tl 3 Transitions For Cast In Place Concrete Barriers written by Nauman Mansoor Sheikh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Automobiles categories.
The objective of this project was to develop transition designs for three cast in place concrete barrier combinations. These included transitions for connecting (a) TxDOT's 36-inch tall Single Slope Traffic Rail (SSTR) to 42-inch tall Single Slope Concrete Barrier (SSCB), (b) 32-inch tall F-shape concrete barrier to SSCB, and (c)TxDOT's 32-inch tall T221 vertical concrete wall to SSCB. The designs were required to meet AASHTO [Manual for Assessing Safety Hardware] MASH Test Level 3 (TL-3) criteria, and their compliance was to be evaluated using a combination of past testing results, impact simulation analyses, and limited full scale testing. Researchers developed designs and reinforcement details for all three transitions. The transition from SSTR to SSCB was comprised of a single slope barrier profile on the traffic side. This design did not require simulation or testing due to the known MASH compliance of the single slope barrier profile. Researchers developed designs of the other two transitions by performing dynamic vehicular impact simulations using MASH TL-3 impact conditions. Using results of these simulations, researchers selected the most critical cases for performance of full scale crash tests. The design selected for full scale testing was the transition between T221 and SSCB. MASH requires performing Test 3-20 (small car) and Test 3-21 (pickup) to evaluate transition designs. Both tests were performed on the transition between T221 and SSCB. The direction of vehicle impact in both tests was from the side of the SSCB to T221, which was selected based on simulation results. The transition performed acceptably in both tests for MASH TL-3 criteria. Based on the results of the simulations for F-shape to SSCB transition, and the fact that the more critical design of T221 to SSCB transition passed MASH testing, the F-shape to SSCB transition was also considered a MASH compliant design. This report provides details of the transition designs, simulation analyses,
Testing And Evaluation Of Mash Tl 3 Transition Between Guardrail And Portable Concrete Barriers
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Author : Robert W. Bielenberg
language : en
Publisher:
Release Date : 2017
Testing And Evaluation Of Mash Tl 3 Transition Between Guardrail And Portable Concrete Barriers written by Robert W. Bielenberg and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Roads categories.
Mash Tl 3 Evaluation Of Guardrail To Rigid Barrier Transition Attached To Bridge Or Culvert Structure
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Author : William F. Williams (Transportation engineer)
language : en
Publisher:
Release Date : 2020
Mash Tl 3 Evaluation Of Guardrail To Rigid Barrier Transition Attached To Bridge Or Culvert Structure written by William F. Williams (Transportation engineer) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Automobiles categories.
Texas Transportation Institute (TTI) researchers performed an extensive literature review of bridge railing transitions crash tested to Manual for Assessing Safety Hardware (MASH) TL-3, and incorporated the information obtained from this review into the design and details for the new transition testing developed for this project. TTI researchers developed concepts for the new transition anchored to a concrete wing wall. TTI researchers developed a full-scale, three-dimensional finite element model of the guardrail transition. The modeling effort included developing and validating a subcomponent level model of the post installed on concrete. Upon completion of the simulations, TTI researchers processed the results and assessed the likelihood of the transition system passing the required MASH crash tests. TTI researchers noted the design deficiencies and recommended design modifications to the system to mitigate those deficiencies. TTI researchers developed full-scale test installation drawings of the design after the finite element model simulations were completed and all the results were reviewed with favorable results. After approval of the test installation drawings by Texas Department of Transportation (TxDOT), construction of a full-scale test installation for crash testing commenced, and crash tests were performed on the full-scale test installation. The Guardrail to Rigid Barrier Transition Attached to Bridge or Culvert Structure, used on the upstream and downstream ends, performed acceptably for MASH TL-3 transitions.