Michael Baker International (United States)

Hartsfield-Jackson Atlanta International Airport (ATL) has consistently ranked as one of the world’s busiest airports for nearly three decades, with roughly 900,000 aircraft operations moving over 100 million passengers annually. Runway 9R/27L is one of two runways in ATL’s five-parallel runway network, which is used primarily for arrivals and is the most heavily utilized for this purpose. This paper explores the present serviceability of the runway pavement by measuring and analyzing current friction properties, groove quality, and surface distress converted to pavement condition index values for the entire width and length of the runway. Results are compared with requirements set forth in FAA Advisory Circular 150/5320-12C and 150/5320-12D (draft version in circulation since 2016).

Cement production requires considerable energy and natural resources, severely impacting the environment due to harmful gas emissions. Coal bottom ash (CBA) and coal boiler slag (CBS), byproducts of coal-fired powerplants having pozzolanic properties, can be mechanically ground and replace cement in concrete, which reduces waste in landfills, preserves natural resources, and reduces health hazards. This study was performed to determine the optimum cement replacement amount of ground CBA (GCBA) and ground CBS (GCBS) in concrete, which was 10% for GCBA and 5% for GCBS. GCBA-based concrete exhibited superior tensile strength, modulus of elasticity, and durability compared to the control. In the Rapid Chloride Penetration Test, 10% GCBA concrete resulted in 2026 coulombs at 56 days, compared to 3405 coulombs for the control, indicating more resistance to chloride penetration. Incorporating 2.5% nanoclay in GCBA-based concrete increased the optimum GCBA content by 5%, and the compressive strength of 15% GCBA concrete increased by 4 MPa. The mortar consisting of the finest GCBA(L1) having Blaine fineness of 3072 g/cm2 yielded the highest compressive strength (32.7 MPa). The study discovered that the compressive strength of GCBA and GCBS-based mortars increases with fineness, and meeting the recommended fineness limit in ASTM C618 enhances concrete or mortar properties.

Background: TIAs serve as an opportunity to identify and modify risk factors and to prevent future events. Given known epidemiologic differences in strokes by race and sex, our objective was to investigate the rates of prior TIAs among those with incident ischemic stroke (IS) in the GCNKSS. Methods: We included all physician adjudicated, incident IS among adults age ≥20 years in the GCNKSS, a population-based stroke surveillance study in a 5-county region of southern Ohio/ northern Kentucky, in 2005, 2010, and 2015. We calculated the frequency of cases in which a TIA (sudden onset of focal neurologic symptoms lasting ≤ 24 hours) was documented in the 365 days prior to IS. Frequencies and proportions of prior TIA were compared by sex, race, and age, and location at which patients sought care for their TIA was described. Finally, multivariable logistic regression was performed to investigate demographic and clinical predictors of cases in which TIA preceded stroke; covariates were chosen a priori. Results: We included 5310 IS events; mean age was 69.7 (SD 14.8) years, 54.7% were female, and 20.4% were Black. A total of 351 patients (6.6%) had a documented TIA the year preceding their IS. Overall, 42.2% did not seek care for their TIA, 21.6% called 911 and/or came to the ED, 6.0% saw a PCP, and 6.6% sought other care. In 22.5% of cases, location of care was unknown. In adjusted results, older age, female sex, history of hypertension, and CAD were associated with having had a prior TIA, while Black race was not. NIHSS was inversely associated with prior TIA (Table). Prior TIAs were similar between study years. Conclusions: We conservatively estimate that ≥ 6% of patients with first-ever IS had a TIA in the preceding year, though underreporting is likely. Many patients did not report seeking care for the TIA, suggesting missed opportunities for risk factor modification. Further research is needed to understand the implications of sex and race differences in frequencies of prior TIA.

Historically, reports of significant problems associated with details featuring intersecting welds in steel bridges have been rare. However, there have been several notable cases involving constraint-induced fracture (CIF). CIF is a particular concern since it can occur in a brittle fashion, suddenly and without warning (different from other types of problems, such as corrosion or fatigue crack growth, for example). CIF generally occurs in details that feature a high degree of constraint (leading to a high level of stress triaxiality), in combination with high levels of tensile stress (particularly from residual stresses) and the presence of a notch-like or crack-like planar discontinuity approximately perpendicular to the primary flow of tensile stress. Details subject to a high degree of constraint often feature the intersection of two or three welded structural elements. The distinction between “intersecting welds” and “constraint resulting from the intersection of welded structural elements” is important. This paper summarizes the findings and recommendations of a recently completed report reflecting the current state of knowledge about CIF in steel bridges. The report is based on a review of previous research, industry practices, and the input of a panel of steel bridge industry experts. It provides a review of the fundamental principles of CIF and presents a general procedure for evaluating steel bridge details for susceptibility to CIF, including examples of assessments of commonly used steel bridge details.

Despite global efforts to monitor, mitigate against, and prevent trash (mismanaged solid waste) pollution, no harmonized trash typology system has been widely adopted worldwide. This impedes the merging of datasets and comparative analyses. We addressed this problem by 1) assessing the state of trash typology and comparability, 2) developing a standardized and harmonized framework of relational tables and tools, and 3) informing practitioners about challenges and potential solutions. We analyzed 68 trash survey lists to assess similarities and differences in classification. We created comprehensive harmonized hierarchical tables and alias tables for item and material classes. On average, the 68 survey lists had 20.8% of item classes in common and 29.9% of material classes in common. Multiple correspondence analysis showed that the 68 surveys were not significantly different regarding organization type, ecosystem focus, or substrate focus. We built the Trash Taxonomy Tool (TTT) web-based application with query features and open access at openanalysis.org/trashtaxonomy. The TTT can be applied to improve, create, and compare trash surveys, and provides practitioners with tools to integrate datasets and maximize comparability. The use of TTT will ultimately facilitate improvements in assessing trends across space and time, identifying targets for mitigation, evaluating the effectiveness of prevention measures, informing policymaking, and holding producers responsible.

Introduction: Stroke patients with a pre-existing disability are less likely to receive acute stroke treatments compared to those without a pre-existing disability. Using the Greater Cincinnati Northern Kentucky (GCNK) Stroke Study, we aimed to understand the disparities in inpatient and outpatient continuum of stroke care according to the patients’ pre-stroke functional status. Methods: We ascertained all hospitalized stroke patients ≥18 years old in year 2015 using ICD-9 430-436; ICD-10 I60-I67, G45-G46 within GCNK population; all cases were physician-reviewed. Per-stroke functional status was ascertained by trained research nurses during medical record review. We compared rates of in-hospital rehabilitative therapies, initiation of stroke prevention treatments, inpatient stroke workup (cardiac/vessel imaging), in-hospital and post-discharge rehabilitative therapies between ischemic stroke patients with pre-stroke modified Rankin score (mRS) 0-1 vs ≥2. Logistic regression was used to evaluate the association between pre-stroke mRS and these outcomes adjusting for age, presenting NIHSS, and insurance status. Results: Of 2476 patients with ischemic stroke in the GCNK population during 2015, 1326 (53%) had a pre-stroke mRS ≥2. Compared to those with pre-stroke mRS 0-1, these patients were less likely to receive complete stroke workup (aOR 0.86 [0.71-1.04]) and certain stroke prevention treatments (aOR 0.46[0.26-0.81], p<0.01), but more likely to require in-hospital and post-discharge rehabilitative therapies (aOR 2.6[2.11-3.21] and 2.27[1.86-2.77], p<0.01, respectively). Conclusions: Ischemic stroke patients with pre-stroke disability were less likely to receive complete in-hospital stroke workup and initiation of certain stroke preventive treatments. Further research into factors driving medical decision-making for stroke patients with a pre-stroke disability is urgently needed to ensure optimal continuum of stroke care.

The recent push to adopt building information modeling (BIM) for bridges and structures in the transportation industry has encountered major barriers owing to the lack of standardization. Unlike the building industry that has the National BIM Standard®–United States (NBIMS-US™) as a formal open platform standard and guide for the development of interoperable BIM software, the transportation industry does not currently have a similar open platform standard to enable the creation of interoperable BIM software to serve the needs of transportation stakeholders. The purpose of this paper is to present the findings of the research for one of the first use cases and development of data exchange requirements and model view definitions in adopting the open platform NBIMS-US applied to bridges and structures for the U.S. transportation industry. A subcommittee of the American Association of State Highway and Transportation Officials and the National Steel Bridge Alliance Steel Bridge Collaboration was formed to conduct a pilot study into the creation of information delivery manuals (IDMs) for steel bridges. This study served as pilot for the development of future IDMs in the transportation industry. As a result, the current IDM for Steel Bridge Detailing and Fabrication serves as the starting point of TPF-5(372) BIM for Bridges and Structures development of the Design to Fabrication model view definition. Finally, this study provided the outcomes and recommendations needed to expedite the development of IDMs for other use cases in the bridge and transportation industry.

Michael Dellosso, PTA, is a Physical Therapy Assistant, Wellspan VNA Home Care, Gettysburg, Pennsylvania. The author declares no conflicts of interest. Address for correspondence: Michael Dellosso, PTA, 516 Baer Ave., Hanover, PA 17331 ([email protected]).

The use of high friction surface treatments (HFST) has become increasingly popular to help improve roadway friction properties and reduce the number of lane-departure and breaking-related accidents. Conventional HFST installation consists of applying an epoxy-resin material to an existing roadway surface and “gluing” a hard, highly angular fine aggregate to the roadway surface. When constructed correctly, skid resistance values (SN40) are often measured in the upper 60s and 70s. However, this functional overlay does not come without potential issues. Performance and service life is strongly dependent on the quality of the construction process, as well the quality of the substrate, which is often difficult to assess in situ. The paper summarizes the forensic testing of three HFST installations in New Jersey—one performing well and two showing premature failure. Testing procedures and preliminary criteria for existing asphalt pavement surfaces were developed to address whether or not epoxy-resin HFST is a viable option. Additionally, the paper summarizes the development and forensic testing of a potential alternative to the epoxy-resin based HFST application. This alternative surface, called a high friction chip seal (HFCS), incorporates the same hard, highly angular fine aggregate but using asphalt binder as the “gluing” medium within the chip seal application process. Three different aggregate sources were evaluated using the HFCS application on Rt 68 in New Jersey. Laboratory testing of the aggregates, as well as field measurements of the test sections, were conducted. It was found that HFCS could be a potential alternative for areas where premature HFST failure is a concern.