Design and Full-Scale Testing of Low-Cost Texas Department of Transportation Type T631 Bridge Rail for MASH Test Level 2 and 3 Applications

2015 ◽  
Vol 2521 (1) ◽  
pp. 117-127
Author(s):  
William F. Williams ◽  
Roger Bligh ◽  
Wade Odell ◽  
Amy Smith ◽  
John Holt
Keyword(s):  
Low Cost ◽  
Department Of Transportation ◽  
Vehicle Performance ◽  
Performance Requirements ◽  
Rail System ◽  
Texas Department ◽  
Level 3 ◽  
Test Level ◽  
Level 2 ◽  
Transportation Type

The purpose of this project was to design and test a low-cost bridge rail system that would be compatible with the Midwest Guardrail System (31 in. height) and minimized or eliminated deck damage when impacted by errant vehicles. The Texas Type T631 bridge rail developed for this project is a flexible, low-cost bridge rail system for Test Level 2 (TL-2) applications. The Texas Department of Transportation Type T631 bridge rail designed and developed for this project was evaluated under Manual for Assessing Safety Hardware (MASH) TL-2 in 2013. The bridge rail incorporated S3X5.7 steel sections designed to yield at the post baseplate. The post baseplate was designed to distribute the baseplate bearing and shear forces without causing damage to the 8-in.-thick reinforced concrete deck. The welds on the posts were designed such that the post yielded without tearing away from the top of the baseplate. The rail element consisted of a 12-gauge W-beam rail element. The rail element was attached to the post with a bolt of diameter 5/16 in. This bolt was designed to break away without adversely affecting vehicle performance. The posts were spaced 6 ft 3 in. on centers for TL-2. The post spacing was reduced to 3 ft 1½ in. on centers and evaluated for MASH Test Level 3 (TL-3) specifications in 2014. At the smaller post spacing, the T631 met all the performance requirements of MASH TL-3. Details of the design and testing of the T631 for MASH TL-2 and MASH TL-3 specifications are provided in this paper.

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.

Evaluation of a Predicted Dynamic Modulus for Florida Mixtures

2005 ◽  
Vol 1929 (1) ◽  
pp. 200-207 ◽  
Author(s):  
Bjorn Birgisson ◽  
Gregory Sholar ◽  
Reynaldo Roque
Keyword(s):  
Dynamic Modulus ◽  
State Agencies ◽  
Department Of Transportation ◽  
University Of Florida ◽  
Florida Department ◽  
Design Guide ◽  
Level 3 ◽  
Pavement Structures ◽  
The University ◽  
Level 2

The new 2002 AASHTO guide for the design of pavement structures is based on mechanistic principles and requires the dynamic modulus as input to compute stress, strain, and rutting and cracking damage in flexible pavements. The 2002 AASHTO guide has three different levels of analysis; the level used depends on the importance of the pavement structure in question. Dynamic modulus testing is required for Level 1 pavement analysis, whereas no laboratory test data are required for Level 2 and Level 3 pavement analysis. Instead, a predictive dynamic modulus equation is used to generate input values. It is of significant importance to state agencies to understand how well the dynamic modulus for locally available materials compares with the predicted dynamic modulus. This paper presents the results of a study by the Florida Department of Transportation and the University of Florida that focused on the evaluation of the dynamic modulus predictive equation used in the new AASHTO 2002 guide for mixtures typical to Florida. The resulting research program consisted of dynamic modulus testing of 28 mixtures common to Florida. Results showed that on average the predictive modulus equation used in the new AASHTO 2002 flexible pavement design guide appeared to work well for Florida mixtures when used with a multiplier to account for the uniqueness of local mixtures. Results of the study also identified optimal viscosity–temperature relationships that result in the closest correspondence between measured and predicted dynamic modulus values.

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.

Retrofit Bridge Rail Design and Testing for a Historic Texas Steel Truss Bridge

2013 ◽  
Vol 2377 (1) ◽  
pp. 29-37
Author(s):  
William Williams
Keyword(s):  
Analytical Procedure ◽  
Design Procedure ◽  
Steel Truss Bridge ◽  
Crash Testing ◽  
Steel Truss ◽  
Level 3 ◽  
Truss Bridge ◽  
Design And Testing ◽  
Test Level ◽  
Level 2

The State Loop 481 steel truss bridge over the Llano River in Junction, Texas, is classified as a historic structure. The bridge is approximately 1,423 ft long and has a railing that attaches directly to the steel truss members and does not meet the current AASHTO Test Level 2 (TL-2) strength requirements. Many supporting truss members were not adequate to resist TL-2 crash force. The purpose of this research was to design a crashworthy retrofit bridge rail that met the current AASHTO TL-2 strength requirements without overstressing the supporting truss members. The new design maintains the historic appearance of the structure. This paper presents details of the new bridge rail design and an analytical procedure for determining the magnitude of force transmitted to the supporting truss members. Crushable-pipe blockouts located between the new retrofit rail design and the truss members were developed as part of this research and were used to minimize the crash force transmitted to the steel truss members. The new bridge rail design was successfully crash tested in accordance with the TL-2 requirements of NCHRP Report 350. A bridge rail expansion splice was developed for the new bridge rail design and was successfully crash tested in accordance with the Test Level 3 requirements of NCHRP Report 350. This paper presents the results of this research, details of the expansion splice, the new bridge rail design, the design procedure, and the results of the crash testing.

Transition from Guardrail to Concrete Bridge Rail for Low-Speed Roadways

2005 ◽  
Vol 1904 (1) ◽  
pp. 20-25
Author(s):  
Roger P. Bligh
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Concrete Bridge ◽  
Transition Systems ◽  
Low Speed ◽  
Traffic Conditions ◽  
Departments Of Transportation ◽  
Test Level ◽  
Level 2 ◽  
Installation Cost

In recent years, many state departments of transportation have had to modify their approach guardrail–to–concrete bridge rail transition systems to comply with the testing requirements of NCHRP Report 350. Generally, these transition systems are designed and tested for use on high-speed roadways. Because no national transition designs have been developed and tested for lower-speed conditions, the same transition standard is typically applied to all roadways regardless of speed. The new transition designs represent a significant increase in installation cost and complexity over some previous designs that were acceptable under NCHRP Report 230. Thus, it may be cost-prohibitive to require use of the same design on all roadways. The purpose of this research was to develop a guardrail–to–concrete bridge rail transition that is suitable for use on lower-speed roadways and that is less expensive and complex than current designs for high-speed roadways. A low-cost transition was successfully evaluated under NCHRP Report 350 Test Level 2 (TL-2) impact conditions. It is considered suitable for use on roadways that have traffic conditions appropriate for the use of TL-2 safety hardware. Use of this system provides significant savings in material and installation cost compared with high-speed (i.e., TL-3) transitions.

Historical text archives and prosopography: the COEL database system

1998 ◽  
Vol 10 (1-3) ◽  
pp. 57-72 ◽  
Author(s):  
K. S. B. Keats-Rohan
Keyword(s):  
Research Tool ◽  
Direct Access ◽  
Specific Situation ◽  
Core Data ◽  
Secondary Sources ◽  
The Core ◽  
Level 3 ◽  
Full Discussion ◽  
Available Information ◽  
Level 2

The COEL database and database software, a combined reference and research tool created by historians for historians, is presented here through Screenshots illustrating the underlying theoretical model and the specific situation to which that has been applied. The key emphases are upon data integrity, and the historian's role in interpreting and manipulating what is often contentious data. From a corpus of sources (Level 1) certain core data are extracted for separate treatment at an interpretive level (Level 3), based upon a master list of the core data (Level 2). The core data are interdependent: each record in Level 2 is of interest in itself; and it either could or should be associated with an(other) record(s) as a specific entity. Sometimes the sources are ambiguous and the association is contentious, necessitating a probabilty-coding approach. The entities created by the association process can then be treated at a commentary level, introducing material external to the database, whether primary or secondary sources. A full discussion of the difficulties is provided within a synthesis of available information on the core data. Direct access to the source texts is only ever a mouse click away. Fully query able, COEL is formidable look-up and research tool for users of all levels, who remain free to exercise an alternative judgement on the associations of the core data. In principle, there is no limit on the type of text or core data that could be handled in such a system.

EVALUASI PELATIHAN DI PT. PUPUK KUJANG CIKAMPEK

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Lania Muharsih ◽  
Ratih Saraswati
Keyword(s):  
Training Evaluation ◽  
Work Productivity ◽  
Learning Behavior ◽  
Level 3 ◽  
Level 1 ◽  
Four Levels ◽  
A Company ◽  
Level 2 ◽  
Evaluation Sheet ◽  
Assessment Factor

This study aims to determine the training evaluation at PT. Kujang Fertilizer. PT. Pupuk Kujang is a company engaged in the field of petrochemicals. Evaluation sheet of PT. Fertilizer Kujang is made based on Kirkpatrick's theory which consists of four levels of evaluation, namely reaction, learning, behavior, and results. At level 1, namely reaction, in the evaluation sheet is in accordance with the theory of Kirkpatrick, at level 2 that is learning should be held pretest and posttest but only made scale. At level 3, behavior, according to theory, but on assessment factor number 3, quantity and work productivity should not need to be included because they are included in level 4. At level 4, that is the result, here is still lacking to get a picture of the results of the training that has been carried out because only based on answers from superiors without evidence of any documents.   Keywords: Training Evaluation, Kirkpatrick Theory.    Penelitian ini bertujuan mengetahui evaluasi training di PT. Pupuk Kujang. PT. Pupuk Kujang merupakan perusahaan yang bergerak di bidang petrokimia. Lembar evaluasi PT. Pupuk Kujang dibuat berdasarkan teori Kirkpatrick yang terdiri dari empat level evaluasi, yaitu reaksi, learning, behavior, dan hasil. Pada level 1 yaitu reaksi, di lembar evaluasi tersebut sudah sesuai dengan teori dari Kirkpatrick, pada level 2 yaitu learning seharusnya diadakan pretest dan posttest namun hanya dibuatkan skala. Pada level 3 yaitu behavior, sudah sesuai teori namun pada faktor penilaian nomor 3 kuantitas dan produktivitas kerja semestinya tidak perlu dimasukkan karena sudah termasuk ke dalam level 4. Pada level 4 yaitu hasil, disini masih sangat kurang untuk mendapatkan gambaran hasil dari pelatihan yang sudah dilaksanakan karena hanya berdasarkan dari jawaban atasan tanpa bukti dokumen apapun.   Kata kunci: Evaluasi Pelatihan, Teori Kirkpatrick.

Variation in antibiotic use across intensive care units (ICU): A population-based cohort study in Ontario, Canada

2020 ◽  
Vol 41 (9) ◽  
pp. 1035-1041
Author(s):  
Erika Y. Lee ◽  
Michael E. Detsky ◽  
Jin Ma ◽  
Chaim M. Bell ◽  
Andrew M. Morris
Keyword(s):  
Cohort Study ◽  
Intensive Care ◽  
Intensive Care Units ◽  
Ventilatory Support ◽  
Severity Of Illness ◽  
Antibiotic Use ◽  
Patient Factors ◽  
Days Of Therapy ◽  
Level 3 ◽  
Level 2

AbstractObjectives:Antibiotics are commonly used in intensive care units (ICUs), yet differences in antibiotic use across ICUs are unknown. Herein, we studied antibiotic use across ICUs and examined factors that contributed to variation.Methods:We conducted a retrospective cohort study using data from Ontario’s Critical Care Information System (CCIS), which included 201 adult ICUs and 2,013,397 patient days from January 2012 to June 2016. Antibiotic use was measured in days of therapy (DOT) per 1,000 patient days. ICU factors included ability to provide ventilator support (level 3) or not (level 2), ICU type (medical-surgical or other), and academic status. Patient factors included severity of illness using multiple-organ dysfunction score (MODS), ventilatory support, and central venous catheter (CVC) use. We analyzed the effect of these factors on variation in antibiotic use.Results:Overall, 269,351 patients (56%) received antibiotics during their ICU stay. The mean antibiotic use was 624 (range 3–1460) DOT per 1,000 patient days. Antibiotic use was significantly higher in medical-surgical ICUs compared to other ICUs (697 vs 410 DOT per 1,000 patient days; P < .0001) and in level 3 ICUs compared to level 2 ICUs (751 vs 513 DOT per 1,000 patient days; P < .0001). Higher antibiotic use was associated with higher severity of illness and intensity of treatment. ICU and patient factors explained 47% of the variation in antibiotic use across ICUs.Conclusions:Antibiotic use varies widely across ICUs, which is partially associated with ICUs and patient characteristics. These differences highlight the importance of antimicrobial stewardship to ensure appropriate use of antibiotics in ICU patients.

scholarly journals An Atmospheric Visibility Grading Method Based on Ensemble Learning and Stochastic Weight Average

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 869
Author(s):  
Xiuguo Zou ◽  
Jiahong Wu ◽  
Zhibin Cao ◽  
Yan Qian ◽  
Shixiu Zhang ◽  
...  
Keyword(s):  
Ensemble Learning ◽  
Traffic Accidents ◽  
Feature Sets ◽  
Atmospheric Visibility ◽  
Average Accuracy ◽  
Level 3 ◽  
Visual Characteristics ◽  
Level 1 ◽  
Grading Model ◽  
Level 2

In order to adequately characterize the visual characteristics of atmospheric visibility and overcome the disadvantages of the traditional atmospheric visibility measurement method with significant dependence on preset reference objects, high cost, and complicated steps, this paper proposed an ensemble learning method for atmospheric visibility grading based on deep neural network and stochastic weight averaging. An experiment was conducted using the scene of an expressway, and three visibility levels were set, i.e., Level 1, Level 2, and Level 3. Firstly, the EfficientNet was transferred to extract the abstract features of the images. Then, training and grading were performed on the feature sets through the SoftMax regression model. Subsequently, the feature sets were ensembled using the method of stochastic weight averaging to obtain the atmospheric visibility grading model. The obtained datasets were input into the grading model and tested. The grading model classified the results into three categories, with the grading accuracy being 95.00%, 89.45%, and 90.91%, respectively, and the average accuracy of 91.79%. The results obtained by the proposed method were compared with those obtained by the existing methods, and the proposed method showed better performance than those of other methods. This method can be used to classify the atmospheric visibility of traffic and reduce the incidence of traffic accidents caused by atmospheric visibility.

scholarly journals Integrating structure and function: mapping the hierarchical spatial heterogeneity of urban landscapes

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Yuguo Qian ◽  
Weiqi Zhou ◽  
Steward T. A. Pickett ◽  
Wenjuan Yu ◽  
Dingpeng Xiong ◽  
...  
Keyword(s):  
Land Cover ◽  
Spatial Heterogeneity ◽  
Urban Ecosystem ◽  
Tree Canopy ◽  
Urban Landscapes ◽  
Shenzhen City ◽  
Object Based ◽  
Level 3 ◽  
Industrial Zones ◽  
Level 2

Abstract Background Cities are social-ecological systems characterized by remarkably high spatial and temporal heterogeneity, which are closely related to myriad urban problems. However, the tools to map and quantify this heterogeneity are lacking. We here developed a new three-level classification scheme, by considering ecosystem types (level 1), urban function zones (level 2), and land cover elements (level 3), to map and quantify the hierarchical spatial heterogeneity of urban landscapes. Methods We applied the scheme using an object-based approach for classification using very high spatial resolution imagery and a vector layer of building location and characteristics. We used a top-down classification procedure by conducting the classification in the order of ecosystem types, function zones, and land cover elements. The classification of the lower level was based on the results of the higher level. We used an object-based methodology to carry out the three-level classification. Results We found that the urban ecosystem type accounted for 45.3% of the land within the Shenzhen city administrative boundary. Within the urban ecosystem type, residential and industrial zones were the main zones, accounting for 38.4% and 33.8%, respectively. Tree canopy was the dominant element in Shenzhen city, accounting for 55.6% over all ecosystem types, which includes agricultural and forest. However, in the urban ecosystem type, the proportion of tree canopy was only 22.6% because most trees were distributed in the forest ecosystem type. The proportion of trees was 23.2% in industrial zones, 2.2% higher than that in residential zones. That information “hidden” in the usual statistical summaries scaled to the entire administrative unit of Shenzhen has great potential for improving urban management. Conclusions This paper has taken the theoretical understanding of urban spatial heterogeneity and used it to generate a classification scheme that exploits remotely sensed imagery, infrastructural data available at a municipal level, and object-based spatial analysis. For effective planning and management, the hierarchical levels of landscape classification (level 1), the analysis of use and cover by urban zones (level 2), and the fundamental elements of land cover (level 3), each exposes different respects relevant to city plans and management.

Sign in / Sign up

Export Citation Format

Share Document