Finite Element Analysis and Long-Term Monitoring of a Highway Overpass Bridge with Newly Constructed Link Slabs and Modified Bearings

2021 ◽  
pp. 036119812110611
Author(s):  
Yifan Zhu ◽  
Kuangyuan Hou ◽  
Chung C. Fu ◽  
Naiyi Li ◽  
Ruel E. Sabellano
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Highway Bridges ◽  
Pilot Project ◽  
Functional Condition ◽  
Element Analysis ◽  
One Year ◽  
The One ◽  
Replacement Design

Joint failure, which causes leakage in bridge decks as well as deterioration in girders and substructures, is one of the most common concerns in highway bridges. Therefore, link slabs have been considered as a preventive maintenance method in eliminating these joints. This paper presents a pilot project that constructed the link slab system in Maryland, U.S., with modified bearings to improve its durability and reduce maintenance costs. Compared with the traditional bearing replacement design for the link slab systems, this project proposes a more economical method by removing the anchor bolts and restricting sliding plates of the fixed bearings at both abutments to match the designed boundary conditions while avoiding the high cost of jacking girders and replacing bearings. Furthermore, numerical analysis and structural health monitoring were conducted and validated to investigate the effectiveness of the link slab design with various high performance concrete materials. After the one-year monitoring period, the link slab system is verified to be in fully functional condition and the bearing modification design is verified to be effective.

scholarly journals Impact of atrial fibrillation pattern on outcomes after left atrial appendage closure: lessons from the prospective LAARGE registry

2021 ◽  
Author(s):  
Shinwan Kany ◽  
Johannes Brachmann ◽  
Thorsten Lewalter ◽  
Ibrahim Akin ◽  
Horst Sievert ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial Appendage ◽  
Systemic Embolism ◽  
Long Term Outcomes ◽  
Increased Risk ◽  
History Of ◽  
One Year ◽  
The One

Abstract Background Non-paroxysmal (NPAF) forms of atrial fibrillation (AF) have been reported to be associated with an increased risk for systemic embolism or death. Methods Comparison of procedural details and long-term outcomes in patients (pts) with paroxysmal AF (PAF) against controls with NPAF in the prospective, multicentre observational registry of patients undergoing LAAC (LAARGE). Results A total of 638 pts (PAF 274 pts, NPAF 364 pts) were enrolled. In both groups, a history of PVI was rare (4.0% vs 1.6%, p = 0.066). The total CHA2DS2-VASc score was lower in the PAF group (4.4 ± 1.5 vs 4.6 ± 1.5, p = 0.033), while HAS-BLED score (3.8 ± 1.1 vs 3.9 ± 1.1, p = 0.40) was comparable. The rate of successful implantation was equally high (97.4% vs 97.8%, p = 0.77). In the three-month echo follow-up, LA thrombi (2.1% vs 7.3%, p = 0.12) and peridevice leak > 5 mm (0.0% vs 7.1%, p = 0.53) were numerically higher in the NPAF group. Overall, in-hospital complications occurred in 15.0% of the PAF cohort and 10.7% of the NPAF cohort (p = 0.12). In the one-year follow-up, unadjusted mortality (8.4% vs 14.0%, p = 0.039) and combined outcome of death, stroke and systemic embolism (8.8% vs 15.1%, p = 0.022) were significantly higher in the NPAF cohort. After adjusting for CHA2DS2-VASc and previous bleeding, NPAF was associated with increased death/stroke/systemic embolism (HR 1.67, 95% CI 1.02–2.72, p = 0.041). Conclusion Atrial fibrillation type did not impair periprocedural safety or in-hospital MACE patients undergoing LAAC. However, after one year, NPAF was associated with higher mortality. Graphic abstract

Accelerated testing of super lightweight UHPC waffle deck under heavy vehicle simulator

2021 ◽  
Vol 16 (2-3) ◽  
pp. 61-74
Author(s):  
Sahar Ghasemi ◽  
Amir Mirmiran ◽  
Yulin Xiao ◽  
Kevin Mackie
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
High Performance Concrete ◽  
High Strength ◽  
Heavy Vehicle ◽  
Wheel Load ◽  
Element Analysis ◽  
Vehicle Simulator ◽  
Pavement Testing ◽  
Heavy Vehicle Simulator

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).

OP457 A Collaborative Horizon Scanning Alert For Disinvestment And Early Awareness

2020 ◽  
Vol 36 (S1) ◽  
pp. 10-10
Author(s):  
Vigdis Lauvrak ◽  
Kelly Farrah ◽  
Rosmin Esmail ◽  
Anna Lien Espeland ◽  
Elisabet Hafstad ◽  
...  
Keyword(s):  
Information Retrieval ◽  
Interest Group ◽  
Pilot Project ◽  
Relevant Information ◽  
Horizon Scanning ◽  
Google Alerts ◽  
One Year ◽  
The One ◽  
New Research ◽  
Google Search

IntroductionIn 2019, the Norwegian Institute for Public Health and Canadian Agency for Drugs and Technologies in Health (CADTH) received support from HTAi to produce a quarterly current awareness alert for the HTAi Disinvestment and Early Awareness Interest Group in collaboration with the HTAi Information Retrieval Interest Group. The alert focuses on methods and topical issues, and broader forecasts of potentially disruptive technologies that may be of interest to those involved in horizon scanning and disinvestment initiatives in health technology assessment (HTA).MethodsInformation specialists at both agencies developed search strategies for disinvestment and for horizon scanning in PubMed and Google. The template for the alert was based on an e-newsletter developed by the Information Retrieval Interest Group. Information specialists and researchers reviewed the monthly (PubMed) and weekly (Google) search results and selected potentially relevant publications. Additional sources were also identified through regular HTA and horizon scanning work.ResultsAlerts are posted quarterly on the HTAi Interest Group website; members receive an email notice when new alerts are available. While the revised PubMed searches are identifying relevant information, Google alerts have been disappointing, and this search may need to be revised further or dropped. When the one-year pilot project ends, in Fall 2020, interest group members will be surveyed to see if the alerts were useful, and whether they have suggestions for improving them.ConclusionsCollaborating on this alert service reduces duplication of effort between agencies, and makes new research in horizon scanning and disinvestment more accessible to colleagues in other agencies working in these areas.

Stochastic Models for Actuarial Use: The Equilibrium Modelling of Local Markets

2009 ◽  
Vol 39 (1) ◽  
pp. 339-370 ◽  
Author(s):  
Robert J. Thomson ◽  
Dmitri V. Gott
Keyword(s):  
Local Market ◽  
Market Participants ◽  
Market Portfolio ◽  
One Year ◽  
The One ◽  
Mean Variance ◽  
Annual Time ◽  
Time Subject

AbstractIn this paper, a long-term equilibrium model of a local market is developed. Subject to minor qualifications, the model is arbitrage-free. The variables modelled are the prices of risk-free zero-coupon bonds – both index-linked and conventional – and of equities, as well as the inflation rate. The model is developed in discrete (nominally annual) time, but allowance is made for processes in continuous time subject to continuous rebalancing. It is based on a model of the market portfolio comprising all the above-mentioned asset categories. The risk-free asset is taken to be the one-year index-linked bond. It is assumed that, conditionally upon information at the beginning of a year, market participants have homogeneous expectations with regard to the forthcoming year and make their decisions in mean-variance space. For the purposes of illustration, a descriptive version of the model is developed with reference to UK data. The parameters produced by that process may be used to inform the determination of those required for the use of the model as a predictive model. Illustrative results of simulations of the model are given.

scholarly journals Quantification of mortality and morbidity in general population of heavily-industrialized city of Abadan: Effect of long-term exposure

2021 ◽  
Author(s):  
Akram Ghorbanian ◽  
Ahmad Jonidi Jafari ◽  
Abbas Shahsavani ◽  
Ali Abdolahnejad ◽  
Majid Kermani ◽  
...  
Keyword(s):  
Air Pollution ◽  
Mortality Data ◽  
Air Pollution Control ◽  
Medical Sciences ◽  
Mortality And Morbidity ◽  
Khuzestan Province ◽  
Vice Chancellor ◽  
One Year ◽  
The One

Introduction: In the 21st century, air pollution has become a global and environmental challenge. The increase in cases of illness and mortality due to air pollution is not hidden from anyone. Therefore, in this study, we estimated the mortality rate due to cause by air pollution agents (PM2.5) in the southernmost city of Khuzestan province (Abadan city) at 2018-2019. Materials and methods: To estimate the mortality duo to air pollution, data related to PM2.5 particles daily concentrations was received from the Abadan Environmental Protection Organization. The average 24-h concentrations of PM2.5 were calculated using Excel. Then, mortality data were obtained from the Vice Chancellor for Health, Abadan University of Medical Sciences. Finally, by AirQ+ software, each of the mortality in 2018-2019 in Abadan was estimated. Results: The obtained data indicated that the concentration of PM2.5 particles within the one-year period was higher than the value set by WHO guideline and EPA standard. Which caused the citizens of Abadan to be exposed to PM2.5 more than 8.23 times than the guidelines of the WHO and 5.34 times more than the standard of the EPA. The output of the model used in this study was as follows: natural mortality (462 cases, AP: 38.25%), mortality duo to LC (6 cases, AP: 32.18%), mortality duo to COPD (8 cases, AP: 26.64%), mortality duo to Stroke (86 cases, AP: 71.26%), mortality duo to IHD (183 cases, AP: 68.34%) and mortality duo to ALRI (2 cases, AP: 32.9%). Conclusion: Planning appropriate strategies of air pollution control to reduce exposure and attributable mortalities is important and necessary.

Development of Some Performance-Based Material Specifications for High-Performance Concrete Pavement

2003 ◽  
Vol 1834 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Prasada Rao Rangaraju
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Pavement ◽  
Performance Criteria ◽  
Test Results ◽  
Department Of Transportation ◽  
Performance Specifications ◽  
Concrete Materials ◽  
Practical Feasibility

In collaboration with FHWA, the Minnesota Department of Transportation (Mn/DOT) has successfully completed its first experimental high-performance concrete pavement (HPCP) project under the Testing and Evaluation Program (TE-30). This project is one of the 22 projects funded under the TE-30 Program. With a structural design life of 60 years, this HPCP is unique in that it incorporates significant changes to the existing Mn/DOT specifications on concrete materials. Some of the new materials-related specifications developed as a part of this project are based on performance criteria that influence long-term durability of the pavement structure. The background and considerations for selecting the new performance measures are discussed, and test results are presented that evaluate the practical feasibility of establishing and achieving the performance specifications.

Long-term predictors of remission in patients treated for medication-overuse headache at a specialized headache center: A prospective cohort study

Cephalalgia ◽  
2016 ◽  
Vol 38 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Jasna J Zidverc-Trajkovic ◽  
Tatjana Pekmezovic ◽  
Zagorka Jovanovic ◽  
Aleksandra Pavlovic ◽  
Milija Mijajlovic ◽  
...  
Keyword(s):  
Cohort Study ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Medication Overuse ◽  
Medication Overuse Headache ◽  
Predictive Values ◽  
One Year ◽  
The One

Objective To evaluate long-term predictors of remission in patients with medication-overuse headache (MOH) by prospective cohort study. Background Knowledge regarding long-term predictors of MOH outcome is limited. Methods Two hundred and forty MOH patients recruited from 2000 to 2005 were included in a one-year follow-up study and then subsequently followed until 31 December 2013. The median follow-up was three years (interquartile range, three years). Predictive values of selected variables were assessed by the Cox proportional hazard regression model. Results At the end of follow-up, 102 (42.5%) patients were in remission. The most important predictors of remission were lower number of headache days per month before the one-year follow-up (HR-hazard ratio = 0.936, 95% confidence interval (CI) 0.884–0.990, p = 0.021) and efficient initial drug withdrawal (HR = 0.136, 95% CI 0.042–0.444, p = 0.001). Refractory MOH was observed in seven (2.9%) and MOH relapse in 131 patients (54.6%). Conclusions Outcome at the one-year follow-up is a reliable predictor of MOH long-term remission.

The Fatigue Performance of High Performance Concrete Composite Girder

2019 ◽  
Author(s):  
C. Xu ◽  
B. Y. Zhang ◽  
Z. H. Hou
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Test Results ◽  
Normal Concrete ◽  
Bending Tests ◽  
Composite Girder ◽  
Tensile Performance ◽  
Negative Bending ◽  
The One ◽  
Push Out

<p>The application of high performance concrete has been increasingly concerned in the negative flexural region of steel‐concrete continuous composite girder because of its favorable tensile performance. However, the unclear cyclic and ultimate performance of a high performance concrete composite girder results to the problems which hinder the further application. In this case, a series of fatigue negative bending tests on HPC composite girders and fatigue push‐out tests on stud connectors in HPC were executed. The test results showed that the fatigue slip in the HPC composite girder was smaller than the normal concrete composite girder, and the fatigue life of stud in HPC was longer than the one in normal concrete. Meanwhile, according to the comparison between the stud fatigue live evaluations and test results, the AASHTO‐based evaluations were comparatively with larger safety redundancy, and JSCE was close to the test results but had smaller safety redundancy.</p>

Sign in / Sign up

Export Citation Format

Share Document