Download or read book Development of a MASH TL 3 Median Barrier Gate written by Roger P. Bligh and published by . This book was released on 2011 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 due to 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/or maintenance vehicles. A new median barrier gate was developed and crash tested under this project. The gate spans a 30-ft opening in a concrete median barrier and consists of two vertically stacked 12-inch x 12-inch x 1/4-inch steel tubes connected to steel end brackets with 2 1/4-inch 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 MASH Test Level 3 (TL-3) impact performance criteria and is considered suitable for implementation on Texas highways where cross-median access is desired.

Download or read book Development and Evaluation of a MASH TL 3 31 inch W beam Median Barrier written by Akram Y. Abu-Odeh and published by . This book was released on 2014 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book MASH TL 3 Transition Between Median Guardrail and Median Concrete Barrier written by Akram Y. Abu-Odeh and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Development of a MASH TL 3 Transition Between Guardrail and Portable Concrete Barriers written by David A. Gutierrez and published by . This book was released on 2014 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).

Download or read book Development of a TL 3 F shape Temporary Concrete Median Barrier written by Ronald K. Faller and published by . This book was released on 1996 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Development of MASH TL 3 Transitions for Cast in Place Concrete Barriers written by Nauman Mansoor Sheikh and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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,

Download or read book Design and MASH TL 3 Evaluation of Surface Mounted Median Guardrail written by Nauman Mansoor Sheikh and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book MASH TL 3 Evaluation of Guardrail to Rigid Barrier Transition Attached to Bridge Or Culvert Structure written by William F. Williams (Transportation engineer) and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book MASH TL 3 Evaluation of the Unreinforced Single slope Concrete Median Barrier written by Robert W. Bielenberg and published by . This book was released on 2018 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ohio Department of Transportation (ODOT) requested an evaluation of an unreinforced, single-slope concrete median barrier capable of satisfying Test Level 3 (TL-3) safety requirements found in the Manual for Assessing Safety Hardware, Second Edition (MASH 2016). The barrier was designed with a height of 42 in. (1,067 mm), a base width of 28 in. (711 mm), and top width of 12 in. (305 mm). The tarmac surface was milled down 1 in. (25 mm) to accommodate the barrier and asphalt pad. The barrier was cast in place using concrete with a minimum compressive strength of 4,000 psi (27.6 MPa). Expansion joints were installed in 20-ft (6.1-m) intervals to simulate cracking and potential barrier discontinuities. An asphalt pad, installed on the milled surface using a tack coat, functioned as the barrier keyway and extended 96 in. (2,438 mm) from the traffic and back sides of the barrier. Previous testing of similar single-slope concrete barriers indicated that only one full-scale crash test (MASH test designation no. 3-11) was needed to satisfy TL-3 criteria. During the test, the 5,001-lb (2,268-kg) pickup impacted the installation at a speed of 62.8 mph (101.0 km/h) and at an angle of 24.9 degrees for an impact severity of 116.3 kip-ft (157.7 kJ). The vehicle was safely contained and redirected, and the test satisfied safety performance evaluation criteria of test designation no. 3-11 found in MASH 2016.

Download or read book Development of a New MASH 2016 TL 3 Portable Barrier System written by Bob W. Bielenberg and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and MASH TL 4 Evaluation of TxDOT Large scupper Median Barrier for Flood prone Areas written by Chiara Silvestri Dobrovolny and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete median barriers are designed to mitigate serious cross-median crashes by preventing penetration of errant vehicles into oncoming traffic. When implemented in flood-prone areas, however, solid concrete median barriers can act as a dam to floodwaters, as recently seen in Texas during Hurricane Harvey or in Louisiana and Pennsylvania following severe storms. These severe weather events raise the height of floodwaters and increase the severity of flooding on highways and surrounding roads and communities. In this study, new median barrier options with openings were investigated as a way to reduce flooding. Finite element simulations were used to aid investigation and evaluation of the designs, and laboratory testing was performed to evaluate the hydraulic efficiency of barrier designs in a variety of simulated flood conditions. A concrete single-slope profile median barrier with a large scupper was selected for crash testing following Manual for Assessing Safety Hardware (MASH) Test Level 4 impact conditions and evaluation criteria. The median barrier design was deemed MASH compliant and is ready for implementation in areas susceptible to flooding, with the goals of reducing flooding severity, decreasing associated risk to motorists, and reducing the level of flood damage to both highways and surrounding areas.

Download or read book Development of a MASH Tl 3 Compliant Parapet Mounted Fence written by Luis Rodriguez Alvizo and published by . This book was released on 2021 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: When roadways pass over railway tracks, there is a risk that debris from the roadway or pedestrians may fall onto the tracks and interfere with railway operations. Because of this, state Departments of Transportation (DOTs) commonly install debris fences in conjunction with bridge rails over railway tracks. However, the safety performance of debris fence systems when impacted by an errant vehicle has not been demonstrated through full-scale crash testing. Thus, the objective of this research was to develop a new, parapet-mounted debris fence for the Iowa DOT according to safety performance guidelines included in the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH 2016) for Test Level 3 (TL-3). In this study, various state DOT fence designs were reviewed and ranked to select a baseline fence system that would be used as the groundwork for the design of the Iowa DOT fence. Furthermore, crash testing, zone of intrusion studies, and anecdotal real-world crashes were reviewed to understand the expected interaction between an errant vehicle impacting a parapet-mounted fence. The new debris fence was then designed to meet severe weather events inducing high winds and ice accumulation. Impact loading was also considered, primarily in the design of the fence-to-barrier connection. The new debris fence and fence terminations were designed and optimized based on crashworthiness, cost, constructability, and aesthetics. Finally, recommendations were provided to accommodate design modifications, such as adaptations to alternate barriers, changes in geographic location, and considerations for MASH TL-4 impact safety criteria.

Download or read book MASH TL 3 Evaluation of the TxDOT TL 3 Low profile Barrier for High Speed Applications written by Chiara Silvestri Dobrovolny and published by . This book was released on 2018 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: In response to the implementation requirements set forth by the Federal Highway Administration, the Texas Department of Transportation Bridge, Design, Maintenance, and Traffic Operations Divisions reviewed their standards for roadside safety devices and identified those devices that require testing and evaluation to assess MASH compliance. Under this phase of the project, the Low-Profile MASH Concrete Barrier (LPCB-13) was evaluated. The objective of this project was to design a TL-3 low-profile barrier for high speed applications and assess its performance according to the safety-performance evaluation guidelines included in MASH for Test Level 3 (TL-3) longitudinal barriers. Based on the detailed computer model simulations results, researchers performed MASH full-scale crash tests on a low-profile portable concrete barrier system comprised of 26-inch tall, 30-ft long barrier segments with a T-shape profile. Based on constructbility feedback, researchers modified the straight side of the barrier to a 1:18 slope, to allow for easiness of construction forming tje TL-3 Low -Profile Barrier performed acceptably as a MASH TL-3 longitudinal barrier.

Download or read book Development and Evaluation of MASH TL 4 Guardrail System written by Nauman Mansoor Sheikh and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers at the Texas A&M Transportation Institute (TTI) designed and tested a Manual for Assessing Safety Hardware (MASH) Test Level 4 (TL-4) compliant metal guardrail system. The researchers first developed several preliminary design concepts of the guardrail system, one of which was selected by the Texas Department of Transportation (TxDOT) for further development through simulation and crash testing. The researchers then developed a full-scale finite element model of the selected system and performed impact simulations under MASH TL-4 impact conditions. Using the results of these impact simulations, the researchers made further improvements to the guardrail design and developed the final system design details for crash testing. TTI then constructed the guardrail installation and performed MASH Test 4-12 with a single unit truck, MASH Test 4-11 with a pickup truck, and MASH Test 4-10 with a small car to meet MASH TL-4 compliance criteria for longitudinal barriers. This report provides details of the guardrail design development, the crash tests and results, and the performance assessment of the guardrail system for MASH TL-4 longitudinal barrier evaluation criteria. The design developed under this research project provides a MASH TL-4 compliant guardrail system that allows TxDOT to provide enhanced roadside safety in corridors that experience above-average heavy vehicle traffic.

Download or read book Development of a MASH TL 3 Approach Guardrail Transition to a MASH TL 4 Steel Bridge Rail written by Jennifer D. Rasmussen and published by . This book was released on 2020 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) approach guardrail transition (AGT) was designed to connect the Midwest Guardrail System (MGS) to a MASH TL-4 steel-post, steel-tube, bridge rail, Type IL-OH. Two connection concepts were evaluated using the LS-DYNA finite element analysis computer software. The second concept was selected for further evaluation with full-scale crash testing, which included a previously-developed, thrie-beam, approach guardrail transition, modified HSS8x6x1/4 transition tube rails that aligned with the lower and middle bridge rail tubes, and new connection hardware designed to prevent vehicle snag during reverse-direction impacts. The critical impact points were selected using LS-DYNA for MASH test designation nos. 3-20 and 3-21 in the impact direction from the thrie-beam to the bridge rail. MASH test designation nos. 3-20 and 3-21 in the impact direction from the bridge rail to the thrie-beam AGT were determined to be non-critical. In test no. STBRT-1, the 2,404-lb small car impacted the AGT at a speed of 64.6 mph, an angle of 25.2 degrees, and at a location 21.3 in. upstream from post no. 19, thus resulting in an impact severity of 60.9 kip-ft. The small car was contained and redirected and resulted in a successful test according to MASH test designation no. 3-20 safety performance criteria. In test no. STBRT-2, the 5,007-lb quad cab pickup truck impacted the AGT at a speed of 62.7 mph, an angle of 24.9 degrees, and at a location 15.9 in. upstream from post no. 19, thus resulting in an impact severity of 116 kip-ft. The pickup truck was contained and redirected and resulted in a successful test according to MASH test designation no. 3-21 safety performance criteria.

Download or read book Development of a MASH TL 3 Compliant Parapet Mounted Fence written by Luis Rodriguez Alvizo and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: When roadways pass over railway tracks, there is a risk that debris from the roadway or pedestrians may fall onto the tracks and interfere with railway operations. Because of this, state Departments of Transportation (DOTs) commonly install debris fences in conjunction with bridge rails over railway tracks. However, the safety performance of debris fence systems when impacted by an errant vehicle has not been demonstrated through full-scale crash testing. Thus, the objective of this research was to develop a new, parapet-mounted debris fence for the Iowa DOT according to safety performance guidelines included in the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH 2016) for Test Level 3 (TL-3). In this study, various state DOT fence designs were reviewed and ranked to select a baseline fence system that would be used as the groundwork for the design of the Iowa DOT fence. Furthermore, crash testing, zone of intrusion studies, and anecdotal real-world crashes were reviewed to understand the expected interaction between an errant vehicle impacting a parapet-mounted fence. The new debris fence was then designed to meet severe weather events inducing high winds and ice accumulation. Impact loading was also considered, primarily in the design of the fence-to-barrier connection. The new debris fence and fence terminations were designed and optimized based on crashworthiness, cost, constructability, and aesthetics. Finally, recommendations were provided to accommodate design modifications, such as adaptations to alternate barriers, changes in geographic location, and considerations for MASH TL-4 impact safety criteria.

Download or read book TL 5 Development of 42 and 51 in Tall Single faced F shape Concrete Barriers written by and published by . This book was released on 2004 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: