Asphalt Plug Joints: Refined Material Tests and Design Guidelines

2000 ◽  
Vol 1740 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Brian K. Bramel ◽  
Charles W. Dolan ◽  
Jay A. Puckett ◽  
Khaled Ksaibati
Keyword(s):  
Rational Design ◽  
Slight Modification ◽  
The United States ◽  
Standard Test ◽  
Design Guidelines ◽  
Full Scale ◽  
Critical Material ◽  
Expansion Joints ◽  
Departments Of Transportation ◽  
Material Tests

Highway builders and rehabilitators throughout the United States use asphalt plug joints (APJs) in bridge expansion joints according to manufacturers’ recommendations. Joint performance varies widely, as indicated in recent surveys. State departments of transportation are installing joints in unsuitable sites or are overlooking other sites where APJs may work well. Rational design guidelines for APJs have been developed. The research suggests suitable applications, material characterization, design guidelines, and validation procedures. Two critical material properties are required to qualify APJ material: relaxation and glass-transition temperature. Both properties may be obtained by using a slight modification of the AASHTO standard thermal specimen, restrained specimen asphalt test. This modified standard test was conducted, and the results were compared with those of the near-full-scale test. Design guidelines are based on field observations, material tests, near-full-scale testing, analytical evaluations, and a survey of the experiences of state departments of transportation. Design recommendations are provided, and joint design changes are proposed to help mitigate the present shortcomings.

Asphalt Plug Joint Usage and Perceptions in the United States

1997 ◽  
Vol 1594 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Brian K. Bramel ◽  
Jay A. Puckett ◽  
Khaled Ksaibati ◽  
Charles W. Dolan
Keyword(s):  
United States ◽  
The United States ◽  
Design Guidelines ◽  
University Of Wyoming ◽  
Survey Results ◽  
The University ◽  
Departments Of Transportation

The University of Wyoming is developing design guidelines for asphalt plug joint use and application under the sponsorship and guidance of the Wyoming and Colorado departments of transportation. As a first step in this research a survey of 50 state departments of transportation was conducted to assess use, perceptions, and installation guidelines. Fifty states responded. The survey results are presented and the trends are summarized.

Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

2000 ◽  
Vol 16 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Louis M. Hsu ◽  
Judy Hayman ◽  
Judith Koch ◽  
Debbie Mandell
Keyword(s):  
Graphical Method ◽  
The United States ◽  
Full Scale ◽  
True Score ◽  
Absolute Value ◽  
Normative Population ◽  
The Us ◽  
The Mean ◽  
And Performance ◽  
Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

Modular Bridge Expansion Joints for Lacey V. Murrow Floating Bridge

1997 ◽  
Vol 1594 (1) ◽  
pp. 163-171 ◽  
Author(s):  
John A. Van Lund ◽  
Mark R. Kaczinski ◽  
Robert J. Dexter
Keyword(s):  
Fatigue Strength ◽  
Fatigue Cracking ◽  
Field Measurements ◽  
The United States ◽  
Limit States ◽  
Expansion Joints ◽  
Lake Washington ◽  
Floating Bridge ◽  
Modular Bridge Expansion Joints ◽  
Washington State Department

The Lacey V. Murrow Bridge (LVM Bridge) is a 2013-m-long floating bridge on Interstate 90 across Lake Washington in Seattle, Washington. Single-support-bar, swivel-joist modular bridge expansion joint systems are located at each end of the bridge between the shore approach spans and the floating pontoons. These joints were designed for 960 mm of longitudinal movement as well as horizontal and vertical rotations caused by wind, wave, temperature, and changes in lake level elevation. A similar joint in an adjacent floating bridge had experienced premature fatigue cracking at welded attachment details because of low fatigue strength. For the LVM Bridge the joint components were fatigue tested and designed by using fatigue limit-states loads, resulting in welded attachment details with improved fatigue strength. In addition, a stiffer center beam and reduced center-beam span lengths produced lower fatigue stress ranges. Joint movements and rotations, fatigue design methodology, results of dynamic analyses, field measurements of the dynamic response, and construction details are described. The total cost of the LVM joints was 1 percent of the final bridge cost. The Washington State Department of Transportation required a 5-year guarantee for the LVM joints. These are the largest modular bridge expansion joints in the United States to be tested and designed for fatigue.

scholarly journals Planning for the First and Last Mile: A Review of Practices at Selected Transit Agencies in the United States

2021 ◽  
Vol 13 (4) ◽  
pp. 2222
Author(s):  
Hossain Mohiuddin
Keyword(s):  
Los Angeles ◽  
Gap Analysis ◽  
The United States ◽  
Design Guidelines ◽  
Plan Implementation ◽  
Marginalized Communities ◽  
Transit Ridership ◽  
Last Mile ◽  
Transit Agencies

A transit trip involves travel to and from transit stops or stations. The quality of what are commonly known as first and last mile connections (regardless of their length) can have an important impact on transit ridership. Transit agencies throughout the world are developing innovative approaches to improving first and last mile connections, for example, by partnering with ride-hailing and other emerging mobility services. A small but growing number of transit agencies in the U.S. have adopted first and last mile (FLM) plans with the goal of increasing ridership. As this is a relatively new practice by transit agencies, a review of these plans can inform other transit agencies and assist them in preparing their own. Four FLM plans were selected from diverse geographic contexts for review: Los Angeles County Metropolitan Transportation Authority (LA Metro), Riverside (CA) Transit Agency (RTA), and Denver Regional Transit District (RTD), and City of Richmond, CA. Based on the literature, we developed a framework with an emphasis on transportation equity to examine these plans. We identified five common approaches to addressing the FLM issue: spatial gap analysis with a focus on socio-demographics and locational characteristics, incorporation of emerging mobility services, innovative funding approaches for plan implementation, equity and transportation remedies for marginalized communities, and development of pedestrian and bicycle infrastructures surrounding transit stations. Strategies in three of the plans are aligned with regional goals for emissions reductions. LA Metro and Riverside Transit incorporate detailed design guidelines for the improvement of transit stations. As these plans are still relatively new, it will take time to evaluate their impact on ridership and their communities’ overall transit experience.

Legalization in context: The design of the WTO’s dispute settlement system

2017 ◽  
Vol 19 (2) ◽  
pp. 304-319 ◽  
Author(s):  
Manfred Elsig
Keyword(s):  
Rational Design ◽  
Dispute Settlement ◽  
The United States ◽  
Settlement System ◽  
Trading System ◽  
Wto Dispute Settlement ◽  
Multilateral Trading System ◽  
The Creation ◽  
Dispute Settlement System

This article asks why the dispute settlement provisions of the multilateral trading system underwent significant reforms during the negotiations that led to the creation of the World Trade Organization (WTO) in 1995. Why did the leading trading powers accept a highly legalized system that departed from established political–diplomatic forms of settling disputes? The contribution of this article is threefold. First, it complements existing accounts that exclusively focus on the United States with a novel explanation that takes account of contextual factors. Second, it offers an in-depth empirical case study based on interviews with negotiators who were involved and novel archival evidence on the creation of the new WTO dispute settlement system. Third, by unpacking the long-standing puzzle of why states designed a highly legalized system, it addresses selected blind spots of the legalization and the rational design literatures with the aim of providing a better understanding about potential paths leading toward significant changes in legalization.

scholarly journals Intrahost Dynamics of Human Cytomegalovirus Variants Acquired by Seronegative Glycoprotein B Vaccinees

2018 ◽  
Vol 93 (5) ◽  
Author(s):  
Cody S. Nelson ◽  
Diana Vera Cruz ◽  
Melody Su ◽  
Guanhua Xie ◽  
Nathan Vandergrift ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Rational Design ◽  
Hcmv Infection ◽  
Vaccine Trial ◽  
The United States ◽  
Glycoprotein B ◽  
Viral Population ◽  
Vaginal Fluid ◽  
The Impact ◽  
Placebo Recipients

ABSTRACTHuman cytomegalovirus (HCMV) is the most common congenital infection worldwide and a frequent cause of hearing loss and debilitating neurologic disease in newborn infants. Thus, a vaccine to prevent HCMV-associated congenital disease is a public health priority. One potential strategy is vaccination of women of child bearing age to prevent maternal HCMV acquisition during pregnancy. The glycoprotein B (gB) plus MF59 adjuvant subunit vaccine is the most efficacious tested clinically to date, demonstrating 50% protection against primary HCMV infection in a phase 2 clinical trial. Yet, the impact of gB/MF59-elicited immune responses on the population of viruses acquired by trial participants has not been assessed. In this analysis, we employed quantitative PCR as well as multiple sequencing methodologies to interrogate the magnitude and genetic composition of HCMV populations infecting gB/MF59 vaccinees and placebo recipients. We identified several differences between the viral dynamics in acutely infected vaccinees and placebo recipients. First, viral load was reduced in the saliva of gB vaccinees, though not in whole blood, vaginal fluid, or urine. Additionally, we observed possible anatomic compartmentalization of gB variants in the majority of vaccinees compared to only a single placebo recipient. Finally, we observed reduced acquisition of genetically related gB1, gB2, and gB4 genotype “supergroup” HCMV variants among vaccine recipients, suggesting that the gB1 genotype vaccine construct may have elicited partial protection against HCMV viruses with antigenically similar gB sequences. These findings suggest that gB immunization had a measurable impact on viral intrahost population dynamics and support future analysis of a larger cohort.IMPORTANCEThough not a household name like Zika virus, human cytomegalovirus (HCMV) causes permanent neurologic disability in one newborn child every hour in the United States, which is more than that for Down syndrome, fetal alcohol syndrome, and neural tube defects combined. There are currently no established effective measures to prevent viral transmission to the infant following HCMV infection of a pregnant mother. However, the glycoprotein B (gB)/MF59 vaccine, which aims to prevent pregnant women from acquiring HCMV, is the most successful HCMV vaccine tested clinically to date. Here, we used viral DNA isolated from patients enrolled in a gB vaccine trial who acquired HCMV and identified several impacts that this vaccine had on the size, distribution, and composition of thein vivoviral population. These results have increased our understanding of why the gB/MF59 vaccine was partially efficacious, and such investigations will inform future rational design of a vaccine to prevent congenital HCMV.

Compatibility of Passenger Vehicles and Cable Median Barrier Systems

2017 ◽  
Author(s):  
Cody S. Stolle ◽  
John D. Reid
Keyword(s):  
United States ◽  
Kinetic Energy ◽  
The United States ◽  
Detailed Data ◽  
Factors Affecting ◽  
Passenger Vehicles ◽  
Complicating Factors ◽  
Departments Of Transportation ◽  
Severe Type ◽  
Trajectory Angle

Cross-median crashes are one of the most severe type of highway crashes. Many state Departments of Transportation (DOTs) install median barriers, such as cable median barriers (CMBs), to reduce the rate of cross-median crashes. Nonetheless, these barriers are not always successful. Approximately 20,000 cable barrier crashes throughout the United States spanning between 1999 and 2010 were examined, and detailed data was sufficient to determine the prevailing causes of 182 penetration crashes (i.e., barrier was breached). Penetration crashes involving CMBs were affected by: (1) impact conditions; (2) barrier placement and design; and (3) vehicle factors, including geometry and inertial properties. In general, CMB crashes occur at higher CG trajectory angles than with other roadside features. The 85th percentile CG trajectory angle for cable barriers was 39 degrees, compared to 25 degrees when all roadside features are considered. Approximately 2.2% of all CMB crashes were severe, although penetrations were between two and thirteen times more likely to be severe than non-penetration crashes. Vehicle factors such as weight and geometrical profile affected the likelihood of CMB penetrations. Headlights or taillights fractured or were damaged in approximately 80% of non-penetration crashes, but were damaged or fractured in less than 60% of penetration crashes, often by additional unrelated impacts. Lastly, heavier vehicles with more kinetic energy were more likely than similar, lighter vehicles to penetrate CMBs. Through better understanding of all of the complicating factors affecting CMB performance, better designs and guidelines can be prepared to maximize CMB effectiveness.

Bled

2018 ◽  
Author(s):  
Lisa Jean Moore
Keyword(s):  
United States ◽  
Health Care ◽  
Quality Control ◽  
Horseshoe Crab ◽  
The United States ◽  
Standard Test ◽  
Nonhuman Animal ◽  
Laboratory Studies ◽  
Health Care Demand ◽  
Horseshoe Crabs

In 1964, Limulus amoebocyte lysate (LAL), developed from horseshoe crab blood, was discovered as an effective pryogen test. Limulus blood reacts to endotoxins by forming a gel. The LAL test, constructed from horseshoe crab amoebocytes, has become the standard test in the United States, Europe, and Asia to test pharmaceutical injectables and pharmaceutical insertables for biomedical and veterinary uses. Without it, endotoxins could contaminate all of our laboratory studies, our bodies, and other nonhuman animal bodies. We’ve made horseshoe crabs indispensable to our human and veterinary biomedicine. We need their blood, and as health care demand grows, we will need more and more. I explain how blood donations are detrimental to the crabs. Furthermore, I explain how the LAL test is a not lifesaving test but is instead used for quality control. Even with all of this information and the viability of a synthetic alternative, the bureaucracy surrounding the procedure for switching to the synthetic alternative will prevent the switch from happening until most of the crabs have died. They are not valued like humans are; they are instead valued for their use to humans and will be valued that way until they are used up.

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